l All the IPv6 routing related configuration mentioned in this manual assumes that the system already operates in IPv4/IPv6 dual-stack mode. For dual stack mode configuration, see the part covering dual stack in the IPv6 Configuration module.

l For a manually established tunnel, routing protocols can be employed on the tunnel interfaces successfully if the tunnel is configured to support expedite termination subnet addresses. While for tunnels of other types, routing protocols cannot be employed on the tunnel interfaces successfully.

1.1 Introduction to IPv6 Static Routing

Static routes are special routes that are manually configured by network administrators. These manually configured static routes work well in simple networks. Configuring and using them properly can improve the performance of networks and can guarantee enough bandwidth reserved for important applications.

However, static routes also have their downside: network failure or topology changes could introduce unreachable routes that lead to network disconnection. Such scenarios require the network administrators to manually configure and modify the static routes.

1.1.1 Features and Functionalities of IPv6 Static Routes

Similar to IPv4 static routes, IPv6 static routes work well in simple IPv6 network environments.

Their major difference lies in the destination and the next hop addresses. IPv6 static routes use IPv6 addresses whereas IPv4 static routes use IPv4 addresses.

1.1.2 Default IPv6 Route

An IPv6 static route that has the destination address configured as “::/0” (indicating a prefix length of 0) is the default IPv6 route. If the destination address of an IPv6 packet does not match any entries in the routing table, this default route will be used to forward the packet.

1.2 Configuring IPv6 Static Routes

In small IPv6 network environments, IPv6 static routes can be used to achieve network connectivity. In comparison to dynamic routes, it helps to save network bandwidth.

1.2.1 Configuration prerequisites

l Enabling IPv6 packet forwarding

l Ensuring that the neighboring nodes are IPv6 reachable

1.2.2 Configuring IPv6 Static Routes

To do…	Use the commands…	Remarks
Enter system view	system-view	—
Configure an IPv6 static route	ipv6 route-static ipv6-address prefix-length [ interface-type interface-number ] nexthop-address [ preference preference-value ]	Required; The default preference of IPv6 static routes is 60..

To do…

Use the commands…

Remarks

Enter system view

system-view

—

Configure an IPv6 static route

ipv6 route-static ipv6-address prefix-length [ interface-type interface-number ] nexthop-address [ preference preference-value ]

Required;

The default preference of IPv6 static routes is 60..

1.3 Displaying and Maintaining IPv6 Static Routes

To do…	Use the command…	Remarks
Display IPv6 static route information	display ipv6 routing-table protocol static [ inactive \| verbose ]	Available in any view
Remove all IPv6 static routes	delete ipv6 static-routes all	Available in system view

& Note:

Using the undo ipv6 route-static command deletes a single IPv6 static route, while using the delete ipv6 static-routes all command deletes all IPv6 static routes including the default route.

1.4 IPv6 Static Routing Configuration Example

I. Network requirements

With IPv6 static routes configured, all hosts and switches can interact with each other.

II. Network diagram

Figure 1-1 Network diagram for static routes

III. Configuration procedure

1) Configure the IPv6 addresses of all VLAN interfaces (Omitted here)

2) Configure IPv6 static routes.

# Configure on SwitchA the default IPv6 static route.

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] ipv6 route-static :: 0 4::2

# Configure two IPv6 static routes on SwitchB.

<SwitchB> system-view

[SwitchB] ipv6

[SwitchB] ipv6 route-static 1:: 64 4::1

[SwitchB] ipv6 route-static 3:: 64 5::1

# Configure on SwitchC the default IPv6 static route.

<SwitchC> system-view

[SwitchC] ipv6

[SwitchC] ipv6 route-static :: 0 5::2

3) Configure the IPv6 addresses of hosts and gateways.

Configure the IPv6 addresses of all the hosts based upon the network diagram, configure the default gateway of PC1 as 1::1, PC2 as 2::1, and PC3 as 3::1.

4) Display configuration information

# Display the IPv6 routing table of SwitchA.

[SwitchA] display ipv6 routing-table

Routing Table :

Destinations : 7 Routes : 7

Destination: ::/0 Protocol : Static

NextHop : 4::2 Preference: 60

Interface : Vlan200 Cost : 0

Destination: ::1/128 Protocol : Direct

NextHop : ::1 Preference: 0

Interface : InLoop0 Cost : 0

Destination: 1::/64 Protocol : Direct

NextHop : 1::1 Preference: 0

Interface : Vlan100 Cost : 0

Destination: 1::1/128 Protocol : Direct

NextHop : ::1 Preference: 0

Interface : InLoop0 Cost : 0

Destination: 4::/64 Protocol : Direct

NextHop : 4::1 Preference: 0

Interface : Vlan200 Cost : 0

Destination: 4::1/128 Protocol : Direct

NextHop : ::1 Preference: 0

Interface : InLoop0 Cost : 0

Destination: FE80::/10 Protocol : Direct

NextHop : :: Preference: 0

Interface : NULL0 Cost : 0

# Verify with the ping command.

[SwitchA] ping ipv6 3::1

PING 3::1 : 56 data bytes, press CTRL_C to break

Reply from 3::1

bytes=56 Sequence=1 hop limit=63 time = 5 ms

Reply from 3::1

bytes=56 Sequence=2 hop limit=63 time = 4 ms

Reply from 3::1

bytes=56 Sequence=3 hop limit=63 time = 4 ms

Reply from 3::1

bytes=56 Sequence=4 hop limit=63 time = 4 ms

Reply from 3::1

bytes=56 Sequence=5 hop limit=63 time = 4 ms

--- 3::1 ping statistics ---

5 packet(s) transmitted

5 packet(s) received

0.00% packet loss

round-trip min/avg/max = 4/4/5 ms

Chapter 2 IPv6-RIPng Configuration

& Note:

l The term “router” and router icon in this document refer to either a router in a generic sense or a Layer 3 switch running routing protocols.

l Verify that the system already operates in IPv4/IPv6 dual-stack mode before configuring IPv6 routing.

2.1 Introduction to RIPng

RIP next generation (RIPng) is an extension of RIP-2 for IPv4. Most RIP concepts are applicable in RIPng.

To adopt RIPng for IPv6 network, the following modifications have been made on basis of RIP:

l UDP port number: RIPng uses UDP port 521 for sending and receiving routing information.

l Multicast address: RIPng uses FF02:9 as the link-local multicast address.

l Destination Prefix: 128-bit destination address prefix.

l Next hop: IPv6 address in 128-bit.

l Source address: RIPng uses FE80::/10 as the link-local source address

2.1.1 RIPng Working Mechanism

RIPng is a routing protocol based on the distance vector (D-V) algorithm. RIPng uses UDP packets to exchange routing information through port 521.

RIPng uses a hop count to measure the distance to the destination. The hop count is referred to as metric or cost. The hop count from a router to the network that the router is directly connected is 0. The hop count from one router to another router is 1, and so on. When the hop count is greater than or equal to 16, the destination network or host is unreachable.

By default, the routing update is sent every 30 seconds. If the router cannot receive routing updates within 180 seconds, the routes learnt from neighbors are considered as fail. After another 240 seconds, if no routing updates are received, the router will remove those routes from the routing table.

RIPng supports Split Horizon and Poison Reverse to prevent routing loops, and route redistribution.

Each RIPng router maintains a routing database, including route entries to all reachable destinations. These route entries contain the following information:

l Destination address: IPv6 address of a host or a network.

l Next hop address: IP address of a neighbor router along the path to the destination.

l Egress interface: Interface that forwards IPv6 packets.

l Metric: Cost from the local router to the destination.

l Routing time: Time elapsed since the routing entry is updated last time. Routing time is reset to 0 each time the routing entry is updated.

l Route tag: It is used for tagging external routes so that the routes can be controlled flexibly in routing policy based on the tags.

2.1.2 RIPng Packet Format

I. Basic format

A RIPng packet consists of a header and multiple route table entries (RTEs). For a RIPng packet, the maximum number of RTEs is related to the MTU of the sending interface.

Figure 2-1 shows the basic packet format of RIPng.

Figure 2-1 RIPng basic packet format

l Command: Type of message. 0x01 indicates Request, 0x02 indicates Response.

l Version: Version of RIPng. It can only be 0x01 for the moment.

l RTE: Route table entry, 20 bytes for each entry.

II. RTE format

There are two types of RTE in RIPng.

l Next hop RTE: Defines a next hop IPv6 address

l IPv6 prefix RTE: Describes the destination IPv6 address and metric in the RIPng routing table.

Figure 2-2 shows format of the next hop RTE

Figure 2-2 Next hop RTE format

IPv6 next hop address is the IPv6 address of the next hop.

Figure 2-3 shows the format of the IPv6 prefix RTE.

Figure 2-3 IPv6 prefix RTE format

l IPv6 prefix: Destination IPv6 address prefix.

l Route tag: Intended to differentiate internal RIP routes from external RIP routes.

l Prefix len: Length of the IPv6 address prefix.

l Metric: Cost of a route.

2.1.3 RIPng Packet Processing Procedure

I. Request packet

When a RIPng router first starts or needs to update part entries in its routing table, the request packet is sent as multicast to ask for routing information from neighbors.

The requested RIPng router processes the received request based on the RTE. If there is only one RTE, and IPv6 prefix and the prefix length is 0 with a metric value of 16, the requested RIPng router will response with the entire routing table. If there are multiple RTEs in a Request message, the requested RIPng router will examine each RTE, update its metric, and send the requested routing information to the requesting router in the response packet.

II. Response packet

The response packet containing the local routing table information is generated under the following conditions:

l Response to a specific request

l Update sent periodically

l Trigged update caused by route changes

Before the router updates its RIPng routing table based on the received response, it must check the validation of the response packet, such as whether the IPv6 address is the link-local address, whether the port number is correct. The response packet failed the check will be discarded.

2.1.4 Protocol Specification

RIPng related specifications are:

l RFC2080: RIPng for IPv6

l RFC2081: RIPng Protocol Applicability Statement

l RFC2453: RIP Version 2

2.2 RIPng Basic Configuration

In this section, you are presented with the information to configure the basic RIPng features.

In the configurations, RIPng should be enabled first. But it is not necessary for RIPng related interface configurations, such as assigning an IPv6 address.

2.2.1 Configuration Prerequisites

Before the configuration, accomplish the following tasks first:

l Enable IPv6 packet forwarding.

l Configure IP address on each interface, and make sure all nodes are reachable.

2.2.2 Configuring the Basic RIPng Function

Follow these steps to configure the basic RIPng function:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Create a RIPng process and enter RIPng view	ripng [ process-id ]	Required Not created by default
Return to system view	quit	—
Enter interface view	interface interface-type interface-number	––
Enable RIPng on a specified interface	ripng process-id enable	Required Disabled by default

& Note:

If RIPng is not enabled on an interface, the interface will not send and receive any RIPng route.

2.3 RIPng Configuration

Before the configuration, accomplish the following tasks first:

l Configure IP address on each interface, and make sure all nodes are reachable.

l Configure RIPng basic functions

l Define an IPv6 ACL before using it for route filtering. Refer to ACL configuration for related information.

l Define the IPv6 address prefix list before using it for route filtering. Refer to 6.2 Defining Filtering Lists

2.3.1 Configuring an Additional Routing Metric

Additional routing metric is an input/output metric added to a RIPng route, including additional metric of sent routes and additional metric of received routes.

The additional metric of a sent route will not change the routing metric in the routing table and will be added only when an interface sends RIPng routing information.

The additional metric of a received route will change the routing metric in the routing table. When an interface receives a valid RIP route, the additional metric will be added to the route before the route is added to the routing table

Follow these steps to configure the RIPng priority and additional routing metric:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Define an additional routing metric for received routes	ripng metricin value	Optional 0 by default
Define an additional routing metric for advertised routes	ripng metricout value	Optional 1 by default

2.3.2 Configuring RIPng Route Summarization

Follow these steps to configure RIPng route summarization

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Advertise a summary IPv6 prefix	ripng summary-address ipv6-address prefix-length	Required

2.3.3 Configuring RIPng to Advertise a Default Route

Follow these steps to configure RIPng default route:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Configure RIPng to advertise a default route	ripng default-route { only \| originate } [ cost value ]	Required By default, RIPng does not advertise any default route.

& Note:

The RIPng default route is forced to send in the update message of the designated interface regardless of whether it exists in the IPv6 routing table.

2.3.4 Configuring a RIPng Route Filtering Policy

You can filter received routing information based on IPv6 ACL or IPv6 prefix list. Only those routes that are not filtered will be added to the RIPng routing table. In addition, you can filter routes to be advertised by the local host, including RIPng routes redistributed from other routing protocols or learned from neighbors. Only routes that satisfy the conditions will be advertised to RIPng neighbors.

Follow these steps to configure a RIPng route filtering policy:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter RIPng view	ripng [ process-id ]	––
Define a filtering policy for received routing information	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } import	Required By default, RIPng does not filter received routing information.
Define a filtering policy for routing information to be advertised	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } export [ protocol [ process-id ] ]	Required By default, RIPng does not filter routing information to be advertised.

2.3.5 Configuring a RIPng Priority

Any routing protocol has its own specific protocol priority. The device can select an optimal route from different protocol routes. You can set a priority for RIPng manually. The smaller the value is, the higher the priority is.

Follow these steps to configure a RIPng priority:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter RIPng view	ripng [ process-id ]	—
Configure a RIPng priority	preference [ route-policy route-policy-name ] value	Optional By default, the value of the RIPng priority is 100.

2.3.6 Configuring RIPng Route Redistribution

Follow these steps to configure RIPng redistributed route:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter RIPng view	ripng [ process-id ]	––
Configure a default routing metric for a redistributed route	default cost value	Optional By default, the default metric of a redistribute route is 0.
Redistribute a route	import-route protocol [ process-id ] [ allow-ibgp ] [ cost cost-value \| route-policy route-policy-name ] *	Required By default, RIPng does not redistribute any other protocol route.

2.4 RIPng Network Adjustment and Optimization

This section describes how to adjust and optimize the performance of the RIPng network as well as applications under special network environments. Before adjusting and optimizing the RIPng network, complete the following tasks:

l Configure a network layer address for an interface

l Configure the basic RIPng function

2.4.1 Configuring RIPng Timers

You can adjust RIPng timers to optimize the performance of the RIPng network.

Follow these steps to configure RIPng timers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter RIPng view	ripng [ process-id ]	—
Configure RIPng timers	timers { garbage-collect garbage-collect-value \| suppress suppress-value \| timeout timeout-value \| update update-value } *	Optional. The RIPng timers have the following defaults: l 30 seconds for the update timer l 180 seconds for the timeout timer l 120 seconds for the suppress timer l 240 seconds for the garbage-collect timer

& Note:

When adjusting RIPng timers, you should consider the network performance and perform unified configurations on routers running RIPng to avoid unnecessary network traffic increase or route oscillation.

2.4.2 Configuring the Split Horizon and Poison Reverse Functions

& Note:

If both the split horizon and poison reverse functions are configured, only the poison reverse function takes effect.

I. Configure the split horizon function

The split horizon function disables a route learned from an interface from being advertised so as to prevent a routing loop between neighbor routers.

Follow these steps to configure the split horizon function:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Enable the split horizon function	ripng split-horizon	Optional Enabled by default

& Note:

Normally you are recommended to enable the split horizon to prevent routing loops.

II. Configuring the poison reverse function

The poison reverse function enables a route learned from an interface to be advertised. However, the metric of the route is set to 16. That is to say, the route is unreachable

Follow these steps to configure poison reverse:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Enable the poison reverse function	ripng poison-reverse	Required Disabled by default

2.4.3 Configuring Zero Field Check for RIPng Packet Headers

Some fields in RIPng packet headers must be zero. These fields are called zero fields. You can enable the zero field check for RIPng packet headers. If any such field contains a non-zero value, the entire RIPng packet will not be processed. If you are sure that all packets are trusty, you can disable the zero field check to save the CPU processing time.

Follow these steps to configure RIPng zero field check:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter RIPng view	ripng [ process-id ]	––
Enable the zero field check for RIPng packer headers	checkzero	Optional Enabled by default

2.4.4 Configuring the Maximum Number of Equivalent Routes

Follow these steps to configure the maximum number of RIPng equivalent routes in load sharing mode:

To do…	Use the command…	Remarks
Enter system view	system-view	––
Enter RIPng view	ripng [ process-id ]	––
Configure the maximum number of equivalent routes in load sharing mode	maximum load-balancing number	Optional By default, the maximum load-balancing is 4.

2.5 Displaying and Maintaining RIPng

To do…	Use the command…	Remarks
Display configuration information of a RIPng process	display ripng [ process-id ]	Available in any view
Display routes in the database advertised by RIPng	display ripng process-id database	Available in any view
Display routing information of the specified RIPng process	display ripng process-id route	Available in any view
Display information of a RIPng interface	display ripng process-id interface [ interface-type interface-number ]	Available in any view

2.6 RIPng Configuration Example

I. Network requirements

As shown in Figure 2-4, all switches run RIPng. Configure Switch B to filter the route (3::/64) learnt from Switch C, which means the route will not be added to the routing table of Switch B, and Switch B will not forward it to Switch A.

II. Network diagram

Figure 2-4 Network diagram for RIPng configuration

III. Configuration procedure

1) Configure the IPv6 address for each interface

Omitted

2) Configure basic RIPng function

# Configure Switch A.

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] ripng 1

[SwitchA-ripng-1] quit

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ripng 1 enable

[SwitchA-Vlan-interface100] quit

[SwitchA] interface vlan-interface 400

[SwitchA-Vlan-interface400] ripng 1 enable

[SwitchA-Vlan-interface400] quit

# Configure Switch B.

<SwitchB> system-view

[SwitchB] ipv6

[SwitchB] ripng 1

[SwitchB-ripng-1] quit

[SwitchB] interface vlan-interface 200

[SwitchB-Vlan-interface200] ripng 1 enable

[SwitchB-Vlan-interface200] quit

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ripng 1 enable

[SwitchB-Vlan-interface100] quit

# Configure Switch C.

<SwitchC> system-view

[SwitchC] ipv6

[SwitchC] ripng 1

[SwitchC-ripng-1] quit

[SwitchC] interface vlan-interface 200

[SwitchC-Vlan-interface200] ripng 1 enable

[SwitchC-Vlan-interface200] quit

[SwitchC] interface vlan-interface 500

[SwitchC-Vlan-interface500] ripng 1 enable

[SwitchC-Vlan-interface500] quit

[SwitchC] interface vlan-interface 600

[SwitchC-Vlan-interface600] ripng 1 enable

[SwitchC-Vlan-interface600] quit

# Display routing table of Switch B.

<SwitchB> display ripng 1 route

Route Flags: A - Aging, S - Suppressed, G - Garbage-collect

----------------------------------------------------------------

Peer FE80::20F:E2FF:FE23:82F5 on Vlan-interface100

Dest 1::/64,

via FE80::20F:E2FF:FE23:82F5, cost 1, tag 0, A, 6 Sec

Dest 2::/64,

via FE80::20F:E2FF:FE23:82F5, cost 1, tag 0, A, 6 Sec

Peer FE80::20F:E2FF:FE00:100 on Vlan-interface200

Dest 3::/64,

via FE80::20F:E2FF:FE00:100, cost 1, tag 0, A, 11 Sec

Dest 4::/64,

via FE80::20F:E2FF:FE00:100, cost 1, tag 0, A, 11 Sec

Dest 5::/64,

via FE80::20F:E2FF:FE00:100, cost 1, tag 0, A, 11 Sec

# Display the routing table of Switch A.

[SwitchA] display ripng 1 route

Route Flags: A - Aging, S - Suppressed, G - Garbage-collect

----------------------------------------------------------------

Peer FE80::200:2FF:FE64:8904 on Vlan-interface100

Dest 1::/64,

via FE80::200:2FF:FE64:8904, cost 1, tag 0, A, 31 Sec

Dest 4::/64,

via FE80::200:2FF:FE64:8904, cost 2, tag 0, A, 31 Sec

Dest 5::/64,

via FE80::200:2FF:FE64:8904, cost 2, tag 0, A, 31 Sec

Dest 3::/64,

via FE80::200:2FF:FE64:8904, cost 1, tag 0, A, 31 Sec

3) Configure Switch B to filter received routes

[SwitchB] acl ipv6 number 2000

[SwitchB-acl6-basic-2000] rule deny source 3::/64

[SwitchB-acl6-basic-2000] rule permit

[SwitchB-acl6-basic-2000] quit

[SwitchB] ripng 1

[SwitchB-ripng-1] filter-policy 2000 import

[SwitchB-ripng-1] filter-policy 2000 export

[SwitchB-ripng-1] quit

# Display routing tables of Switch B and Switch A.

[SwitchB] display ripng 1 route

Route Flags: A - Aging, S - Suppressed, G - Garbage-collect

----------------------------------------------------------------

Peer FE80::20F:E2FF:FE23:82F5 on Vlan-interface100

Dest 1::/64,

via FE80::20F:E2FF:FE23:82F5, cost 1, tag 0, A, 2 Sec

Dest 2::/64,

via FE80::20F:E2FF:FE23:82F5, cost 1, tag 0, A, 2 Sec

Peer FE80::20F:E2FF:FE00:100 on Vlan-interface200

Dest 4::/64,

via FE80::20F:E2FF:FE00:100, cost 1, tag 0, A, 5 Sec

Dest 5::/64,

via FE80::20F:E2FF:FE00:100, cost 1, tag 0, A, 5 Sec

[SwitchA] display ripng 1 route

Route Flags: A - Aging, S - Suppressed, G - Garbage-collect

----------------------------------------------------------------

Peer FE80::20F:E2FF:FE00:1235 on Vlan-interface100

Dest 1::/64,

via FE80::20F:E2FF:FE00:1235, cost 1, tag 0, A, 2 Sec

Dest 4::/64,

via FE80::20F:E2FF:FE00:1235, cost 2, tag 0, A, 2 Sec

Dest 5::/64,

via FE80::20F:E2FF:FE00:1235, cost 2, tag 0, A, 2 Sec

Chapter 3 IPv6-OSPFv3 Configuration

& Note:

l The term “router” and router icon in this document refer to either a router in a generic sense or a Layer 3 switch running routing protocols.

l Verify that the system already operates in IPv4/IPv6 dual-stack mode before configuring IPv6 routing.

3.1 Introduction to OSPFv3

3.1.1 OSPFv3 Overview

OSPFv3 is OSPF (Open Shortest Path First) version 3 for short, supporting IPv6 and compliant with RFC2740 (OSPF for IPv6).

Unchanged parts between OSPFv3 and OSPFv2:

l 32 bits router ID and area ID

l Packets: Hello, DD (Data Description), LSR (Link State Request), LSU (Link State Update), LSAck (Link State Acknowledgment)

l Mechanisms for finding neighbors and establishing adjacencies

l Mechanisms for LSA flooding and aging

Differences between OSPFv3 and OSPFv2:

l OSPFv3 now runs on a per-link basis, instead of on a per-IP-subnet basis.

l OSPFv3 supports multiple instances per link.

l OSPFv3 identifies neighbors by Router IDs, while OSPFv2 by IP addresses.

3.1.2 OSPFv3 Packets

OSPFv3 has also five types of packets: hello, DD, LSR, LSU, and LSAck.

The five packets have the same packet header, which different from the OSPFv2 packet header is only 16 bytes in length, has no authentication field, but added with an Instance ID field to support multi-instance per link.

Figure 3-1 gives the OSPFv3 packet header.

Figure 3-1 OSPFv3 packet header

Major fields:

l Version #: Version of OSPF, which is 3 for OSPFv3.

l Type: Type of OSPF packet, from 1 to 5 are hello, DD, LSR, LSU, and LSAck respectively.

l Packet Length: Packet length in bytes, including header.

l Instance ID: Instance ID for a link.

l 0: Reserved, which must be 0.

3.1.3 OSPFv3 LSA Types

OSPFv3 sends routing information in LSAs, which as defined in RFC2740 have the following types:

l Router-LSAs: Originated by all routers. This LSA describes the collected states of the router's interfaces to an area. Flooded throughout a single area only.

l Network-LSAs: Originated for broadcast and NBMA networks by the Designated Router. This LSA contains the list of routers connected to the network. Flooded throughout a single area only.

l Inter-Area-Prefix-LSAs: Similar to Type 3 LSA of OSPFv2, originated by ABRs (Area Border Routers), and flooded throughout the LSA's associated area. Each Inter-Area-Prefix-LSA describes a route with IPv6 address prefix to a destination outside the area, yet still inside the AS (an inter-area route).

l Inter-Area-Router-LSAs: Similar to Type 4 LSA of OSPFv2, originated by ABRs and flooded throughout the LSA's associated area. Each Inter-Area-Router-LSA describes a route to ASBR (Autonomous System Boundary Router).

l AS-external-LSAs: Originated by ASBRs, and flooded throughout the AS (except Stub and NSSA areas). Each AS-external-LSA describes a route to another Autonomous System. A default route can be described by an AS external LSA.

l Link-LSAs: A router originates a separate Link-LSA for each attached link. Link-LSAs have link-local flooding scope. Each Link-LSA describes the IPv6 address prefix of the link and Link-local address of the router,

l Intra-Area-Prefix-LSAs: Each Intra-Area-Prefix-LSA contains IPv6 prefix information on a router, stub area or transit area information, and has area flooding scope. It was introduced because Router-LSAs and Network-LSAs contain no address information now.

3.1.4 Timers of OSPFv3

Timers in OSPFv3 include:

l OSPFv3 packet timer

l LSA delay timer

l SPF timer

I. OSPFv3 packet timer

Hello packets are sent periodically between neighboring routers for finding and maintaining neighbor relationships, or for DR/BDR election. The hello interval must be identical on neighboring interfaces. The smaller the hello interval, the faster the network convergence speed and the bigger the network load.

If a router receives no hello packet from a neighbor after a period, it will declare the peer is down. The period is called dead interval.

After sending an LSA to its adjacency, a router waits for an acknowledgment from the adjacency. If no response received after retransmission interval elapses, the router will send again the LSA. The retransmission interval must be longer than the round-trip time in between.

II. LSA delay time

Each LSA has an age in the local LSDB (incremented by 1 per second), but an LSA is not aged on transmission. You need to add an LSA delay time into the age time before transmission, which is important for low speed networks.

III. SPF timer

Whenever LSDB changes, SPF recalculation happens. If recalculations become so frequent, a large amount of resources will be occupied, reducing operation efficiency of routers. You can adjust SPF calculation interval and delay time to protect networks from being overloaded due to frequent changes.

3.1.5 OSPFv3 Features Supported

l Basic features defined in RFC2740

l OSPFv3 stub area

l OSPFv3 multi-process, which enable a router to run multiple OSPFv3 processes

3.1.6 Related RFCs

l RFC2740: OSPF for IPv6

l RFC2328: OSPF Version 2

3.2 IPv6-OSPFv3 Configuration Task List

To configure OSPFv3, perform the tasks described in the following sections:

Task		Description
Configuring OSPFv3 Basic Functions		Required
Configuring OSPFv3 Area Parameters	Configuring an OSPFv3 Stub Area	Optional
Configuring OSPFv3 Area Parameters	Configuring OSPFv3 Virtual Links	Optional
Configuring OSPFv3 Routing Information Management	Configuring OSPFv3 Route Summarization	Optional
	Configuring OSPFv3 Inbound Route Filtering	Optional
	Configuring Link Costs for OSPFv3 Interfaces	Optional
	Configuring the Maximum Number of OSPFv3 Load-balancing Routes	Optional
	Configuring OSPFv3 Route Redistribution	Optional
Configuring OSPFv3 Network Optimization	Configuring OSPFv3 Timers	Optional
	Configuring the DR Priority for an Interface	Optional
	Ignoring MTU Check for DD Packets	Optional
	Disable Interfaces from Sending OSPFv3 Packets	Optional

3.3 Configuring OSPFv3 Basic Functions

3.3.1 Prerequisites

l Make neighboring nodes accessible with each other at network layer.

l Enable IPv6 packet forwarding

3.3.2 Configuring OSPFv3 Basic Functions

To configure OSPFv3 basic functions, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enable OSPFv3 and enter its view	ospfv3 [ process-id ]	Required
Specify a router ID	router-id router-id	Required
Enter interface view	interface interface-type interface-number	—
Enable OSPFv3 on the interface	ospfv3 process-id area area-id [ instance instance-id ]	Required Not enabled by default

& Note:

l Configure an OSPFv3 process ID when enabling OSPFv3. The process ID takes effect locally, without affecting packet exchange between routers.

l When configuring a router ID, make sure each router has a unique ID. If a router runs multiple OSPFv3 processes, you need to specify a router ID for each process.

l You need to specify a router ID manually, which is necessary to make OSPFv3 work.

3.4 Configuring OSPFv3 Area Parameters

The stub area and virtual link support of OSPFv3 has the same principle and application environments with OSPFv2.

Splitting an OSPFv3 AS into multiple areas reduces the number of LSAs on networks and extends OSPFv3 application. For those non-backbone areas residing on the AS boundary, you can configure them as Stub areas to further reduce the size of routing tables on routers in these areas and the number of LSAs.

Non-backbone areas exchange routing information via the backbone area. Therefore, the backbone and non-backbone areas, including the backbone itself must maintain connectivity. In practice, necessary physical links may not be available for connectivity. You can configure virtual links to address it.

3.4.1 Prerequisites

l Enable IPv6 packet forwarding

l Configure OSPFv3 basic functions

3.4.2 Configuring an OSPFv3 Stub Area

To configure an OSPFv3 stub area, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Enter OSPFv3 area view	area area-id	Required
Configure the area as a stub area	stub [ no-summary ]	Required Not configured by default
Configure the default route cost of sending a packet to the stub area	default-cost value	Optional Defaults to 1

& Note:

l Configurations on routers attached to the same area should be compatible to avoid information exchange failures even information block and routing loop.

l You cannot delete an OSPFv3 area directly. Only when you remove all configurations in area view and all interfaces attached to the area become down, can the area be removed automatically.

l All routers attached to a stub area must be configured with the stub command. The keyword no-summary is only available on the ABR.

l If you use the stub command with the keyword no-summary on an ABR, the ABR distributes a default summary LSA into the area rather than generating an AS-external-LSA or Inter-Area-Prefix-LSA. The stub area of this kind is also known as totally stub area.

3.4.3 Configuring OSPFv3 Virtual Links

You can configure virtual links to maintain connectivity between non-backbone areas and the backbone, or in the backbone itself.

To configure a virtual link, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Enter OSPFv3 area view	area area-id	Required
Create and configure a virtual link	vlink-peer router-id [ hello seconds \| retransmit seconds \| trans-delay seconds \| dead seconds \| instance instance-id ] *	Required

& Note:

Both ends of a virtual link are ABRs that are configured with the vlink-peer command.

3.5 Configuring OSPFv3 Routing Information Management

This section is to configure management of OSPF routing information advertisement and reception, and route redistribution from other protocols.

3.5.1 Prerequisites

l Enable IPv6 packet forwarding

l Configure OSPFv3 basic functions

3.5.2 Configuring OSPFv3 Route Summarization

To configure route summarization between areas, use the following command on a ABR:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Enter OSPFv3 area view	area area-id	Required
Configure a summary route	abr-summary ipv6-address prefix-length [ not-advertise ]	Required Not configured by default

& Note:

The abr-summary command is available on ABRs only. If contiguous network segments are available in an area, you can use the command to summarize them into one network segment on the ABR. The ABR will advertise only the summary route. Any LSA falling into the specified network segment will not be advertised, reducing the LSDB size in other areas.

3.5.3 Configuring OSPFv3 Inbound Route Filtering

You can configure OSPFv3 to filter routes that are computed from received LSAs according to some rules.

To configure inbound route filtering, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Configure inbound route filtering	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } import	Required Not configured by default

& Note:

Use of the filter-policy import command can only filter routes computed by OSPFv3. Only routes not filtered can be added into the local routing table.

3.5.4 Configuring Link Costs for OSPFv3 Interfaces

You can configure OSPFv3 link costs for interfaces to adjust routing calculation.

To configure the link cost for an OSPFv3 interface, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter interface view	interface interface-type interface-number	—
Configure the cost for the interface	ospfv3 cost value [ instance instance-id ]	Optional By default, The cost value defaults to 1.

3.5.5 Configuring the Maximum Number of OSPFv3 Load-balancing Routes

If multiple routes to a destination are available, using load balancing to send IPv6 packets on these routes in turn can improve link utility. To configure the maximum number of load-balancing routes, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Specify the maximum number of load-balancing routes	maximum load-balancing maximum	Optional By default, the maximum number of load-balancing routes supported by OSPFv3 is four

3.5.6 Configuring OSPFv3 Route Redistribution

To configure OSPFv3 route redistribution, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Specify a default cost for redistributed routes	default cost value	Optional Defaults to 1
Redistribute routes from other protocols, including from other OSPFv3 processes	import-route { isisv6 process-id \| ospfv3 process-id \| ripng process-id \| bgp4+ [ allow-ibgp ] \| direct \| static } [ cost value \| type type \| route-policy route-policy-name ] *	Required Not configured by default
Configure to filter redistributed routes	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } export [ isisv6 process-id \| ospfv3 process-id \| ripng process-id \| bgp4+ \| direct \| static]	Optional Not configured by default

& Note:

l Using the import-route command on a router makes the router become an ASBR.

l Since OSPFv3 is a link state based routing protocol, it cannot directly filter LSAs to be advertised. Therefore, you need to configure filtering redistributed routes before advertising routes that are not filtered in LSAs into the routing domain.

l Use of the filter-policy export command takes effect only on the local router. However, if the import-route command is not configured, executing the filter-policy export command does not take effect.

3.6 Configuring OSPFv3 Network Optimization

This section describes configurations of OSPFv3 timers, interface DR priority, MTU check ignorance for DD packets, disabling interfaces from sending OSPFv3 packets.

OSPFv3 timers:

l Packet timer: Specified to adjust topology convergence speed and network load

l LSA delay timer: Specified especially for low speed links

l SPF timer: Specified to protect networks from being over consumed due to frequent network changes.

For a broadcast network, you can configure DR priorities for interfaces to affect DR/BDR election.

By disabling an interface from sending OSPFv3 packets, you can make other routers on the network obtain no information from the interface.

3.6.1 Prerequisites

l Enable IPv6 packet forwarding

l Configure OSPFv3 basic functions

3.6.2 Configuring OSPFv3 Timers

To configure OSPFv3 timers, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter interface view	interface interface-type interface-number	—
Configure hello interval	ospfv3 timer hello seconds [ instance instance-id ]	Optional Defaults to 10 seconds.
Configure dead interval	ospfv3 timer dead seconds [ instance instance-id ]	Optional Defaults to 40 seconds.
Configure LSA retransmission interval	ospfv3 timer retransmit interval [ instance instance-id ]	Optional Defaults to 5 seconds
Configure LSA transmission delay	ospfv3 trans-delay seconds [ instance instance-id ]	Optional Defaults to 1 second
Exit to system view	quit	—
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Configure SPF timer	spf timers delay-interval hold-interval	Optional delay-interval defaults to 5 seconds; hold-interval defaults to 10 seconds

& Note:

l The dead interval set on neighboring interfaces cannot be so small. Otherwise, a neighbor is so easy to be considered as down.

l The LSA retransmission interval cannot be so small to avoid unnecessary retransmissions.

3.6.3 Configuring the DR Priority for an Interface

To configure the DR priority for an interface, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter interface view	interface interface-type interface-number	—
Configure the DR priority	ospfv3 dr-priority priority [ instance instance-id ]	Optional Defaults to 1

& Note:

The DR priority of an interface determines the interface’s qualification in DR election. Interfaces having the priority 0 cannot become a DR or BDR.

3.6.4 Ignoring MTU Check for DD Packets

When LSAs are few, it is unnecessary to check MTU in DD packets in order to improve efficiency.

To ignore MTU check for DD packets, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter interface view	interface interface-type interface-number	—
Ignore MTU check for DD packets	ospfv3 mtu-ignore [ instance instance-id ]	Required Not ignored by default

3.6.5 Disable Interfaces from Sending OSPFv3 Packets

To disable interfaces from sending any OSPFv3 packet, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	-
Enter OSPFv3 view	ospfv3 [ process-id ]	Required
Disable interfaces from sending any OSPFv3 packet	silent-interface { interface-type interface-number \| all }	Required Not disabled by default

& Note:

l Multiple processes can disable the same interface from sending OSPFv3 packets. Use of the silent-interface command disables only the interfaces associated with the current process rather than interfaces associated with other processes.

l After an OSPF interface is set to silent, direct routes of the interface can still be advertised in Intra-Area-Prefix-LSAs via other interfaces, but hello packets for finding neighbors cannot be advertised, so no neighboring relationship can be established on the interface, enhancing adaptability of OSPFv3 networking.

3.7 Displaying and Maintaining OSPFv3

To do…	Use the command…	Remarks
Display OSPFv3 debugging state information	display debugging ospfv3	Available in any view
Display OSPFv3 process brief information	display ospfv3 [ process-id ]
Display OSPFv3 interface information	display ospfv3 interface [ interface-type interface-number \| statistic ]
Display OSPFv3 LSDB information	display ospfv3 [ process-id ] lsdb [ [ external \| inter-prefix \| inter-router \| intra-prefix \| link \| network \| router ] [ link-state-id ] [ originate-router router-id ] \| total ]
Display LSA statistics in OSPFv3 LSDB	display ospfv3 lsdb statistic
Display OSPFv3 neighbor information	display ospfv3 [ process-id ] [ area area-id ] peer [ [ interface-type interface-number ] [ verbose ] \| peer-router-id ]
Display OSPFv3 neighbor statistics	display ospfv3 peer statistic
Display OSPFv3 routing table information	display ospfv3 [ process-id ] routing [ ipv6-address prefix-length \| ipv6-address /prefix-length \| abr-routes \| asbr-routes \| all \| statistics ]
Display OSPFv3 area topology information	display ospfv3 [ process-id ] topology [ area area-id ]
Display OSPFv3 virtual link information	display ospfv3 [ process-id ] vlink
Display OSPFv3 next hop information	display ospfv3 [ process-id ] next-hop
Display OSPFv3 link state request list information	display ospfv3 [ process-id ] request-list [ statistics ]
Display OSPFv3 link state retransmission list information	display ospfv3 [ process-id ] retrans-list [ statistics ]
Display OSPFv3 statistics	display ospfv3 statistic

3.8 OSPFv3 Configuration Examples

3.8.1 Configuring OSPFv3 Areas

I. Network requirements

In Figure 3-2, all switches run OSPFv3. The AS is split into three areas, in which, Switch B and Switch C act as ABRs to forward routing information between areas.

It is required to configure Area 2 as a stub area, reducing LSAs into the area without affecting route reachability.

II. Network diagram

Figure 3-2 Network diagram for OSPFv3 area configuration

III. Configuration procedure

1) Configure IPv6 addresses for interfaces (omitted)

2) Configure OSPFv3 basic functions

# Configure Switch A.

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] ospfv3

[SwitchA-ospfv3-1] router-id 1.1.1.1

[SwitchA-ospfv3-1] quit

[SwitchA] interface vlan-interface 300

[SwitchA-Vlan-interface300] ospfv3 1 area 1

[SwitchA-Vlan-interface300] quit

[SwitchA] interface vlan-interface 200

[SwitchA-Vlan-interface200] ospfv3 1 area 1

[SwitchA-Vlan-interface200] quit

# Configure Switch B

<SwitchB> system-view

[SwitchB] ipv6

[SwitchB] ospfv3

[SwitchB-ospf-1] router-id 2.2.2.2

[SwitchB-ospf-1] quit

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ospfv3 1 area 0

[SwitchB-Vlan-interface100] quit

[SwitchB] interface vlan-interface 200

[SwitchB-Vlan-interface200] ospfv3 1 area 1

[SwitchB-Vlan-interface200] quit

# Configure Switch C

<SwitchC> system-view

[SwitchC] ipv6

[SwitchC] ospfv3

[SwitchC-ospfv3-1] router-id 3.3.3.3

[SwitchC-ospfv3-1] quit

[SwitchC] interface vlan-interface 100

[SwitchC-Vlan-interface100] ospfv3 1 area 0

[SwitchC-Vlan-interface100] quit

[SwitchC] interface vlan-interface 400

[SwitchC-Vlan-interface400] ospfv3 1 area 2

[SwitchC-Vlan-interface400] quit

# Configure Switch D

<SwitchD> system-view

[SwitchD] ipv6

[SwitchD] ospfv3

[SwitchD-ospfv3-1] router-id 4.4.4.4

[SwitchD-ospfv3-1] quit

[SwitchD] interface Vlan-interface 400

[SwitchD-Vlan-interface400] ospfv3 1 area 2

[SwitchD-Vlan-interface400] quit

# Display OSPFv3 neighbor information on Switch B.

[SwitchB] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

3.3.3.3 1 Full/DR 00:00:39 Vlan100 0

OSPFv3 Area ID 0.0.0.1 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

1.1.1.1 1 Full/Backup 00:00:38 Vlan200 0

# Display OSPFv3 neighbor information on Switch C.

[SwitchC] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

2.2.2.2 1 Full/Backup 00:00:39 Vlan100 0

OSPFv3 Area ID 0.0.0.2 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

4.4.4.4 1 Full/DR 00:00:38 Vlan400 0

# Display OSPFv3 routing table information on Switch D.

[SwitchD] display ospfv3 routing

E1 - Type 1 external route, IA - Inter area route, I - Intra area route

E2 - Type 2 external route, * - Selected route

OSPFv3 Router with ID (4.4.4.4) (Process 1)

------------------------------------------------------------------------

*Destination: 2001::/64

Type : IA Cost : 2

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

*Destination: 2001:1::/64

Type : IA Cost : 3

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

*Destination: 2001:2::/64

Type : I Cost : 1

NextHop : directly-connected Interface: Vlan400

*Destination: 2001:3::/64

Type : IA Cost : 4

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

3) Configure Area 2 as a stub area

# Configure Switch D

[SwitchD] ospfv3

[SwitchD-ospfv3-1] area 2

[SwitchD-ospfv3-1-area-0.0.0.2] stub

# Configure Switch C, with the default route cost to the stub area being 10.

[SwitchC] ospfv3

[SwitchC-ospfv3-1] area 2

[SwitchC-ospfv3-1-area-0.0.0.2] stub

[SwitchC-ospfv3-1-area-0.0.0.2] default-cost 10

# Display OSPFv3 routing table information on Switch D. You can find a default route is added, whose cost is the cost of the directly connected route plus the configured cost.

[SwitchD] display ospfv3 routing

E1 - Type 1 external route, IA - Inter area route, I - Intra area route

E2 - Type 2 external route, * - Selected route

OSPFv3 Router with ID (4.4.4.4) (Process 1)

------------------------------------------------------------------------

*Destination: ::/0

Type : IA Cost : 11

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

*Destination: 2001::/64

Type : IA Cost : 2

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

*Destination: 2001:1::/64

Type : IA Cost : 3

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

*Destination: 2001:2::/64

Type : I Cost : 1

NextHop : directly-connected Interface: Vlan400

*Destination: 2001:3::/64

Type : IA Cost : 4

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

4) Configure Area 2 as a totally stub area

# Configure Switch C, the ABR, to make Area 2 as a totally stub area.

[SwitchC-ospfv3-1-area-0.0.0.2] stub no-summary

# Display OSPFv3 routing table information on Switch D. You can find route entries are reduced. All non directly connected routes are removed except the default route.

[SwitchD] display ospfv3 routing

E1 - Type 1 external route, IA - Inter area route, I - Intra area route

E2 - Type 2 external route, * - Selected route

OSPFv3 Router with ID (4.4.4.4) (Process 1)

------------------------------------------------------------------------

*Destination: ::/0

Type : IA Cost : 11

NextHop : FE80::F40D:0:93D0:1 Interface: Vlan400

*Destination: 2001:2::/64

Type : I Cost : 1

NextHop : directly-connected Interface: Vlan400

3.8.2 Configuring OSPFv3 DR Election

I. Network requirements

In Figure 3-3:

l The priority of Switch A is 100, the highest priority on the network, so it will be the DR.

l The priority of Switch C is 2, the second highest priority on the network, so it will be the BDR.

l The priority of Switch B is 0, so it cannot become the DR.

l RouterD has the default priority 1.

II. Network diagram

Figure 3-3 Network diagram for OSPFv3 DR election configuration

III. Configuration procedure

1) Configure IPv6 addresses for interfaces (omitted)

2) Configure OSPFv3 basic functions

# Configure Switch A

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] ospfv3

[SwitchA-ospfv3-1] router-id 1.1.1.1

[SwitchA-ospfv3-1] quit

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ospfv3 1 area 0

[SwitchA-Vlan-interface100] quit

# Configure Switch B

<SwitchB> system-view

[SwitchB] ipv6

[SwitchB] ospfv3

[SwitchB-ospfv3-1] router-id 2.2.2.2

[SwitchB-ospfv3-1] quit

[SwitchB] interface vlan-interface 200

[SwitchB-Vlan-interface200] ospfv3 1 area 0

[SwitchB-Vlan-interface200] quit

# Configure Switch C

<SwitchC> system-view

[SwitchC] ipv6

[SwitchC] ospfv3

[SwitchC-ospfv3-1] router-id 3.3.3.3

[SwitchC-ospfv3-1] quit

[SwitchC] interface vlan-interface 100

[SwitchC-Vlan-interface100] ospfv3 1 area 0

[SwitchC-Vlan-interface100] quit

# Configure Switch D

<SwitchD> system-view

[SwitchD] ipv6

[SwitchD] ospfv3

[SwitchD-ospfv3-1] router-id 4.4.4.4

[SwitchD-ospfv3-1] quit

[SwitchD] interface vlan-interface 200

[SwitchD-Vlan-interface200] ospfv3 1 area 0

[SwitchD-Vlan-interface200] quit

# Display neighbor information on Switch A. You can find routers have the same default DR priority 1. In this case, the router with the highest Router ID is elected as the DR, so Switch D is the DR, Switch C is the BDR.

[SwitchA] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

2.2.2.2 1 2-Way/DROther 00:00:36 Vlan200 0

3.3.3.3 1 Full/Backup 00:00:35 Vlan100 0

4.4.4.4 1 Full/DR 00:00:33 Vlan200 0

# Display neighbor information on Switch D. You can find neighbor states between Router D and other routers are all full.

[SwitchD] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

1.1.1.1 1 Full/DROther 00:00:30 Vlan100 0

2.2.2.2 1 Full/DROther 00:00:37 Vlan200 0

3.3.3.3 1 Full/Backup 00:00:31 Vlan100 0

3) Configure DR priorities for interfaces.

# Configure the DR priority of Vlan-interface100 as 100 on Switch A.

[SwitchA] interface Vlan-interface 100

[SwitchA-Vlan-interface100] ospfv3 dr-priority 100

[SwitchA-Vlan-interface100] quit

# Configure the DR priority of Vlan-interface 200 as 0 on Switch B.

[SwitchB] interface vlan-interface 200

[SwitchB-Vlan-interface200] ospfv3 dr-priority 0

[SwitchB-Vlan-interface200] quit

#Configure the DR priority of Switch C as 2.

[SwitchC] interface Vlan-interface 100

[SwitchC-Vlan-interface100] ospfv3 dr-priority 2

[SwitchC-Vlan-interface100] quit

# Display neighbor information on Switch A. You can find DR priorities have been updated, but DR and BDR are not changed.

[SwitchA] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

2.2.2.2 0 2-Way/DROther 00:00:38 Vlan200 0

3.3.3.3 2 Full/Backup 00:00:32 Vlan100 0

4.4.4.4 1 Full/DR 00:00:36 Vlan200 0

#Display neighbor information on Switch D. You can find Switch D is still the DR.

[SwitchD] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

1.1.1.1 100 Full/DROther 00:00:33 Vlan100 0

2.2.2.2 0 Full/DROther 00:00:36 Vlan200 0

3.3.3.3 2 Full/Backup 00:00:40 Vlan100 0

4) Restart DR/BDR election

# Use the shutdown and undo shutdown commands on interfaces to restart DR/BDR election (omitted).

# Display neighbor information on Switch A. You can find Switch C becomes the BDR.

[SwitchA] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

2.2.2.2 0 Full/DROther 00:00:31 Vlan200 0

3.3.3.3 2 Full/Backup 00:00:39 Vlan100 0

4.4.4.4 1 Full/DROther 00:00:37 Vlan200 0

# Display neighbor information on Switch D. You can find Switch A becomes the DR.

[SwitchD] display ospfv3 peer

OSPFv3 Area ID 0.0.0.0 (Process 1)

----------------------------------------------------------------------

Neighbor ID Pri State Dead Time Interface Instance ID

1.1.1.1 100 Full/DR 00:00:34 Vlan100 0

2.2.2.2 0 2-Way/DROther 00:00:34 Vlan200 0

3.3.3.3 2 Full/Backup 00:00:32 Vlan100 0

3.9 Troubleshooting OSPFv3 Configuration

3.9.1 No OSPFv3 Neighbor Relationship Established

I. Symptom

No OSPF neighbor relationship can be established.

II. Analysis

If the physical link and lower protocol work well, check OSPF parameters configured on interfaces. The two neighboring interfaces must have the same parameters, such as the area ID, network segment and mask, network type. If the network type is broadcast, at least one interface must have a DR priority higher than 0.

III. Process steps

1) Display neighbor information using the display ospfv3 peer command.

2) Display OSPFv3 interface information using the display ospfv3 interface command.

3) Ping the neighbor router’s IP address to check connectivity.

4) Check OSPF timers. The dead interval on an interface must be at least four times the hello interval.

5) On a broadcast network, at least one interface must have a DR priority higher than 0.

3.9.2 Incorrect Routing Information

I. Symptom

OSPFv3 cannot find routes to other areas.

II. Analysis

The backbone area must maintain connectivity to all other areas. If a router connects to more than one area, at least one area must be connected to the backbone. The backbone cannot be configured as a Stub area.

In a Stub area, all routers cannot receive external routes, and all interfaces connected to the Stub area must be associated with the Stub area.

III. Process steps

1) Use the display ospfv3 peer command to display OSPFv3 neighbors.

2) Use the display ospfv3 interface command to display OSPFv3 interface information.

3) Use the display ospfv3 lsdb command to display Link State Database information to check integrity.

4) Display information about area configuration using the display current-configuration configuration command. If more than two areas are configured, at least one area is connected to the backbone.

5) In a Stub area, all routers are configured with the stub command.

6) If a virtual link is configured, use the display ospf vlink command to check the neighbor state.

Chapter 4 IPv6-IS-IS Configuration

& Note:

l The term “router” and router icon in this document refer to either a router in a generic sense or a Layer 3 switch running routing protocols.

l Verify that the system already operates in IPv4/IPv6 dual-stack mode before configuring IPv6 routing.

4.1 Introduction to IPv6-IS-IS

The IS-IS routing protocol (Intermediate System-to-Intermediate System intra-domain routing information exchange protocol) supports multiple network protocols, including IPv6. The IS-IS with IPv6 support is called IPv6-IS-IS dynamic routing protocol. The International Engineer Task Force (IETF) defines the IPv6 protocol for IS-IS in the file draft-ietf-isis-ipv6-05. Two type-length-values (TLVs) and a new network layer protocol identifier (NLPID) are added to support IPv6 protocol.

The TLV is a variable field in the link state PDUs (LSP). The two TLVs are:

l IPv6 Reachability: Defines the prefix, metric and other information to indicate the network reachability, with type 236 (0xEC).

l IPv6 Interface Address: A corresponding TLV as the IP Interface Address in IPv4, which transforms the 32 bits IPv4 address to 128 bits IPv6 address.

NLPID is an 8-bit field with a value of 142 (0x8E). If the IS-IS router supports IPv6, the routing information is advertised with the NLPID.

4.2 IPv6-IS-IS Basic Configuration

& Note:

You can implement IPv6 networking through IPv6-IS-IS in IPv6 network environment.

4.2.1 Configuration Prerequisites

Before the configuration, accomplish the following tasks first:

l Enable IPv6 globally

l Configure IP address on each interface, and make sure all nodes are reachable.

l Enable IS-IS

4.2.2 Configuring IPv6-IS-IS Basic Functions

Follow these steps to configure the basic functions of IPv6-IS-IS

To do…	Use command to…	Remarks
Enter system view	system-view	––
Create an IS-IS process and enter IS-IS view	isis [ process-id ]	Required Not enabled by default
Set the network entity name of the IS-IS process	network-entity net	Required Not configured by default
Enable IPv6 in the IS-IS process	ipv6 enable	Required Disabled by default
Go back to system view	quit	––
Enter interface view	interface interface-type interface-number	––
Enable IPv6-IS-IS on a specified interface	isis ipv6 enable [ process-id ] [ silent ]	Required Disabled by default

4.3 Configuring IPv6-IS-IS Routing Information Control

4.3.1 Configuration Prerequisites

& Note:

You need finish basic IPv6-IS-IS configuration before configuring IPv6-IS-IS routing features.

4.3.2 Configuration Procedure

Follow these steps to configure IPv6-IS-IS routing information control:

To do…	Use command to…			Remarks
Enter system view	system-view			––
Enter IS-IS view	isis [ process-id ]			––
Define the routing priority of IPv6-IS-IS	ipv6 preference { route-policy route-policy-name \| preference-value }*			Optional 15 by default
Configure route summarization of IPv6-IS-IS	ipv6 summary ipv6-prefix prefix-length [ avoid-feedback \| generate_null0_route \| [ level-1 \| level-1-2 \| level-2 ] \| tag tag-value ] *			Optional Disabled by default
Define an IPv6-IS-IS default route	ipv6 default-route-advertise [ [ level-1 \| level-2 \| level-1-2 ] \| route-policy route-policy-name ]*			Optional No IPv6-IS-IS default route is defined by default.
Configure IPv6 IS-IS to filter received routes	ipv6 filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name \| route-policy route-policy-name } import			Optional No filtering policy is defined by default
Configure IPv6 IS-IS to redistribute routes from another routing protocol	ipv6 import-route protocol [ process-id \| allow-ibgp ] [ cost cost-value \| [ level-1 \| level-2 \| level-1-2 ] \| route-policy route-policy-name \| tag tag-value ]*			Optional Not configured by default
Define the filtering policy for redistributed route	ipv6 filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name \| route-policy route-policy-name } export [ protocol process-id ]			Optional Do not filter the redistributed route by default.
Enable route leaking	ipv6 import-route isisv6 level-2 into level-1 [ filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name \| route-policy route-policy-name } \| tag tag-value ]*			Optional Not enabled by default.
Define the maximum number of the load balance		ipv6 maximum load-balancing number	Optional 4 by default

& Note:

The ipv6 filter-policy export command, usually used in combination with the ipv6 import-route command, filters the distributed route when advertising it to other routers. If no protocol parameter is specified, all distributed protocols will be filtered.

4.4 Displaying and Maintaining IPv6-IS-IS

To do…	Use the command…	Remarks
Display brief information of IS-IS	display isis brief	Available in any view
Display the status of the debug switch	display isis debug-switches process-id	Available in any view
Display information of the IS-IS enabled interface	display isis interface [ verbose ] [ process-id ]	Available in any view
Display information of the IS-IS license	display isis license	Available in any view
Display the LSDB information	display isis lsdb [ [ l1 \| l2 \| level-1 \| level-2 ] \| [ [ lsp-id lsp-id \| lsp-name lspname ] \| local \| verbose ]* [ process-id ]	Available in any view
Display the IS-IS mesh group	display isis mesh-group [ process-id ]	Available in any view
Display the mapping table between the host name and system ID	display isis name-table [ process-id ]	Available in any view
Display information of the IS-IS peer	display isis peer [ verbose ] [ process-id ]	Available in any view
Display the IS-IS routing information	display isis route ipv6 [ [ level-1 \| level-2 ] \| verbose ]* [ process-id ]	Available in any view
Display information of the SPF log	display isis spf-log [ process-id ]	Available in any view
Display statistic information of the IS-IS process	display isis statistics [ level-1 \| level-2 \| level-1-2 ] [ process-id ]	Available in any view
Clear IS-IS configuration data	reset isis all [ process-id ]	Available in user view
Clear the IS-IS data information of a neighbor	reset isis peer system-id [ process-id ]	Available in user view

4.5 IPv6-IS-IS Configuration Example

I. Network requirements

As shown in Figure 4-1, connect and enable IS-IS over IPv6 on Switch A, Switch B, Switch C and Switch D within an autonomous system.

Switch A and Switch B are Level-1 switches, Switch D is Level-2 switch, and Switch C is a Level-1-2 switch connecting two areas. Switch A, Switch B, Switch C are in area 10, while Switch D is in area 20.

II. Network diagram

Figure 4-1 Network diagram for IPv6-IS-IS basic configuration

III. Configuration procedure

1) Configure IPv6 address for each interface

Omitted

2) Configure basic IPv6-IS-IS functions

# Configure Switch A.

<SwitchA> system-view

[SwitchA] isis 1

[SwitchA-isis-1] is-level level-1

[SwitchA-isis-1] network-entity 10.0000.0000.0001.00

[SwitchA-isis-1] ipv6 enable

[SwitchA-isis-1] quit

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] isis ipv6 enable 1

[SwitchA-Vlan-interface100] quit

# Configure Switch B.

<SwitchB> system-view

[SwitchB] isis 1

[SwitchB-isis-1] is-level level-1

[SwitchB-isis-1] network-entity 10.0000.0000.0002.00

[SwitchB-isis-1] ipv6 enable

[SwitchB-isis-1] quit

[SwitchB] interface vlan-interface 200

[SwitchB-Vlan-interface200] isis ipv6 enable 1

[SwitchB-Vlan-interface200] quit

# Configure Switch C.

<SwitchC> system-view

[SwitchC] isis 1

[SwitchC-isis-1] network-entity 10.0000.0000.0003.00

[SwitchC-isis-1] ipv6 enable

[SwitchC-isis-1] quit

[SwitchC] interface vlan-interface 100

[SwitchC-Vlan-interface100] isis ipv6 enable 1

[SwitchC-Vlan-interface100] quit

[SwitchC] interface vlan-interface 200

[SwitchC-Vlan-interface200] isis ipv6 enable 1

[SwitchC-Vlan-interface200] quit

[SwitchC] interface vlan-interface 300

[SwitchC-Vlan-interface300] isis ipv6 enable 1

[SwitchC-Vlan-interface300] quit

# Configure Switch D.

<SwitchD> system-view

[SwitchD] isis 1

[SwitchD-isis-1] is-level level-2

[SwitchD-isis-1] network-entity 20.0000.0000.0004.00

[SwitchD-isis-1] ipv6 enable

[SwitchD-isis-1] quit

[SwitchD] interface vlan-interface 300

[SwitchD-Vlan-interface300] isis ipv6 enable 1

[SwitchD-Vlan-interface300] quit

[SwitchD] interface vlan-interface 301

[SwitchD-Vlan-interface301] isis ipv6 enable 1

[SwitchD-Vlan-interface301] quit

Chapter 5 IPv6-BGP4+ Configuration

& Note:

l This chapter describes only configuration for BGP4+. For BGP-related information, refer to the part covering BGP configuration in the IPv4 Routing module.

l Verify that the system already operates in IPv4/IPv6 dual-stack mode before configuring IPv6 routing.

5.1 BGP4+ Overview

The traditional BGP-4 manages only IPv4 routing information, thus other network layer protocols such as IPv6 are limited when traveling across ASs.

To support multiple network layer protocols, IETF extended BGP-4 by introducing BGP4+ that is defined in RFC 2858 (Multiprotocol Extensions for BGP-4).

To implement IPv6 support, BGP4+ reflects IPv6 network layer information into attributes of Network Layer Reachable Information (NLRI) and NEXT_HOP.

NLRI attribute of BGP4+ involves:

l MP_REACH_NLRI: Multiprotocol Reachable NLRI, for advertisement of next hop information of reachable routes.

l MP_UNREACH_NLRI: Multiprotocol Unreachable NLRI, for withdrawal of unreachable routes.

NEXT_HOP attribute of BGP4+ is identified by IPv6 address, which is an IPv6 unicast address or local link address.

BGP4+ utilizes BGP multiprotocol extensions for application in IPv6 networks. The original message and routing mechanism of BGP is not changed.

5.2 Configuration Task List

Task		Description
Configuring BGP4+ Basic Functions	Configuring an IPv6 Peer	Required
	Advertising a Local IPv6 Route	Optional
	Configuring a Preferred Value for Routes Received from a Peer/Peer Group	Optional
	Specifying a Local Update Source Interface to a Peer/Peer Group	Optional
	Configuring a Non Direct EBGP Connection to a Peer/Peer Group	Optional
	Configuring Description for a Peer/Peer Group	Optional
	Establishing No Session to a Peer/Peer Group	Optional
	Logging Session State and Event Information of a Peer/Peer Group	Optional
Controlling Route Distribution and Reception	Configuring BGP4+ Route Redistribution	Optional
	Advertising Default Route to a Peer/Peer Group	Optional
	Configuring Route Distribution Policy	Optional
	Configuring Route Reception Policy	Optional
	Configuring BGP4+ and IGP Route Synchronization	Optional
	Configuring Route Dampening	Optional
Configuring BGP4+ Route Attributes	Configuring BGP4+ Preference and Default LOCAL_PREF and NEXT_HOP Attributes	Optional
	Configuring the MED Attribute	Optional
	Configuring the AS_PATH Attribute	Optional
Adjusting and Optimizing BGP4+ Networks	Configuring BGP4+ Timers	Optional
	Configuring BGP4+ Soft Reset	Optional
	Configuring the Maximum Number of Load-Balancing Routes	Optional
Configuring a Large Scale BGP4+ Network	Configuring BGP4+ Peer Group	Optional
	Configuring BGP4+ Community	Optional
	Configuring a BGP4+ Router Reflector	Optional

5.3 Configuring BGP4+ Basic Functions

5.3.1 Prerequisites

Before configuring this task, you have

l Specified IP addresses for interfaces.

l Enabled IPv6 function.

You need to decide on:

l Local AS number and Router ID

l Peer IPv6 address and AS number

l Source interface of updates

5.3.2 Configuring an IPv6 Peer

To configure an IPv6 peer, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required Not enabled by default
Specify a router ID	router-id router-id	Optional Required if no IP addresses configured for Loopback interface and other interfaces
Enter IPv6 address family view	ipv6-family	—
Specify an IPv6 peer and its AS number	peer ipv6-address as-number as-number	Required Not configured by default

5.3.3 Advertising a Local IPv6 Route

To advertise a local route into the routing table, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Advertise a local route into BGP4+ routing table	network ipv6-address prefix-length [ short-cut \| route-policy route-policy-name ]	Required Not advertised by default

5.3.4 Configuring a Preferred Value for Routes Received from a Peer/Peer Group

To configure a preferred value for routes received from a peer/peer group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure a preferred value for routes received from a peer/peer group	peer { ipv6-group-name \| ipv6-address } preferred-value value	Optional By default, the preferred value is 0.

5.3.5 Specifying a Local Update Source Interface to a Peer/Peer Group

To specify a local update source interface connected to a peer, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Specify a local update source interface connected to a peer	peer { ipv6-group-name \| ipv6-address } connect-interface interface-type interface-number	Required By default, the source interface of the optimal updates is used.

& Note:

To improve stability and reliability, you can specify the local interface of a BGP4+ connection as loopback interface. By doing so, a connection failure upon redundancy available will not affect BGP4+ connection.

5.3.6 Configuring a Non Direct EBGP Connection to a Peer/Peer Group

To configure an EBGP connection to a peer not directly connected, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure a non direct EBGP connection to a peer/peer group	peer { ipv6-group-name \| ipv6-address } ebgp-max-hop [ hop-count ]	Required Not configured by default

Caution:

In general, direct links should be available between EBGP peers. If not available, you can use the peer ebgp-max-hop command to establish a multi-hop TCP connection in between. However, you need not use this command for direct EBGP connection using loopback interfaces.

5.3.7 Configuring Description for a Peer/Peer Group

To configure description for a peer/peer group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure description for a peer/peer group	peer { ipv6-group-name \| ipv6-address } description description-text	Optional Not configured by default

& Note:

The peer group for which to configure description must have been created.

5.3.8 Establishing No Session to a Peer/Peer Group

To disable session establishment to a peer/peer group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Disable session establishment to a peer/peer group	peer { ipv6-group-name \| ipv6-address } ignore	Optional Not disabled by default

5.3.9 Logging Session State and Event Information of a Peer/Peer Group

To log on the session and event information of a peer/peer group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enable global logging	log-peer-change	Optional Enabled by default
Enter IPv6 address family view	ipv6-family	—
Enable to log session and event information of a peer/peer group	peer { ipv6-group-name \| ipv6-address } log-change	Optional Enabled by default

& Note:

Refer to BGP Commands in IPv4 Routing for information about the log-peer-change command.

5.4 Controlling Route Distribution and Reception

The task includes routing information filtering, routing policy application and route dampening.

5.4.1 Prerequisites

Before configuring this task, you have:

l Enabled IPv6 function

l Configured BGP4+ basic functions

You need to decide on:

l ACL number

l Routing policy names on both distribution and reception directions

l Route dampening parameters: half-life, threshold values

5.4.2 Configuring BGP4+ Route Redistribution

To configure BGP4+ route redistribution and filtering, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Enable to redistribute default route into the BGP4+ routing table	default-route imported	Optional Not enabled by default
Enable to redistribute routes from other routing protocols	import-route protocol [ process-id ] [ med med-value \| route-policy route-policy-name ]*	Required Not enabled by default

& Note:

If the default-route imported command is not configured, using the import-route command cannot redistribute any IGP default route.

5.4.3 Advertising Default Route to a Peer/Peer Group

To advertise default route to a peer/peer group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Advertise a default route to a peer/peer group	peer { ipv6-group-name \| ipv6-address } default-route-advertise [ route-policy route-policy-name ]	Required Not advertised by default

& Note:

With the peer default-route-advertise command used, the local router advertises a default route with itself as the next hop to the specified peer/peer group, regardless of whether the default route is available in the routing table.

5.4.4 Configuring Route Distribution Policy

To configure policies for route distribution, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Filter advertised routes	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } export [ protocol process-id ]	Required Not filtered by default
Apply a routing policy to routes advertised to a peer/peer group	peer { ipv6-group-name \| ipv6-address } route-policy route-policy-name export	Required Not applied by default
Specify an IPv6 ACL to filer routes advertised to a peer/peer group	peer { ipv6-group-name \| ipv6-address } filter-policy acl6-number export	Required Not specified by default
Specify an AS path ACL to filer routes advertised to a peer/peer group	peer { ipv6-group-name \| ipv6-address } as-path-acl as-path-acl-number export	Required Not specified by default
Specify an IPv6 prefix list to filer routes advertised to a peer/peer group	peer { ipv6-group-name \| ipv6-address } ipv6-prefix ipv6-prefix-name export	Required Not specified by default

& Note:

l Members of a peer group must have the same outbound route policy with the peer group.

l BGP4+ advertises routes not filtered by the specified policy to peers. Using the protocol argument can filter only the specified protocol routes. If no protocol specified, BGP4+ filters all routes to be advertised, including redistributed routes and routes imported using the network command.

5.4.5 Configuring Route Reception Policy

To configure route reception policy, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required Not enabled by default
Enter IPv6 address family view	ipv6-family	—
Filter received routes	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } import	Required Not filtered by default
Apply a routing policy to routes imported from a peer/peer group	peer { ipv6-group-name \| ipv6-address } route-policy route-policy-name import	Required Not applied by default
Specify an ACL to filter routes imported from a peer/peer group	peer { ipv6-group-name \| ipv6-address } filter-policy acl6-number import	Required Not specified by default
Specify an AS path ACL to filter routing information imported from a peer/peer group	peer { ipv6-group-name \| ipv6-address } as-path-acl as-path-acl-number import	Required Not specified by default
Specify an IPv6 prefix list to filter routing information imported from a peer/peer group	peer { ipv6-group-name \| ipv6-address } ipv6-prefix ipv6-prefix-name import	Required Not specified by default
Specify the upper limit of address prefixes imported from a peer/peer group	peer { ipv6-group-name \| ipv6-address } route-limit limit [ percentage ]	Optional By default, no limit on prefixes

& Note:

l Only routes not filtered by the specified policy can be added into the local BGP4+ routing table.

l Members of a peer group can have different inbound route policies.

5.4.6 Configuring BGP4+ and IGP Route Synchronization

With this feature enabled and when a non-BGP4+ router is responsible for forwarding packets in an AS, BGP4+ speakers in the AS cannot advertise routing information to outside ASs unless all routers in the AS know the latest routing information.

By default, when a BGP4+ router receives an IBGP route, it only checks the reachability of the route’s next hop before advertisement. If the synchronization feature is configured, only the IBGP route is advertised by IGP can the route be advertised to EBGP peers.

To configure BGP4+ and IGP route synchronization, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Enable route synchronization between BGP4+ and IGP	synchronization	Required Not enabled by default

5.4.7 Configuring Route Dampening

To configure BGP route dampening, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure BGP4+ route dampening parameters	dampening [ half-life-reachable half-life-unreachable reuse suppress ceiling \| route-policy route-policy-name ]*	Optional Not configured by default

5.5 Configuring BGP4+ Route Attributes

This section describes how to use BGP4+ route attributes to modify BGP4+ routing policy. These attributes are:

l BGP4+ protocol preference

l Default LOCAL_PREF attribute

l MED attribute

l NEXT_HOP attribute

l AS_PATH attribute

5.5.1 Prerequisites

Before configuring this task, you have:

l Enabled IPv6 function

l Configured BGP4+ basic functions

5.5.2 Configuring BGP4+ Preference and Default LOCAL_PREF and NEXT_HOP Attributes

To do so, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure preference values for BGP4+ external, internal, local routes	preference { external-preference internal-preference local-preference \| route-policy route-policy-name }	Optional The default preference values of external, internal and local routes are 255, 255, 130 respectively
Configure the default value for local preference	default local-preference value	Optional The value defaults to 100
Advertise routes to a peer/peer group with the local router as the next hop	peer { ipv6-group-name \| ipv6-address } next-hop-local	Optional By default, the feature is available for routes advertised to the EBGP peer/peer group, but not available to the IBGP peer/peer group

& Note:

l To make sure an IBGP peer can find the correct next hop, you can configure routes advertised to the peer to use the local router as the next hop. If BGP load balancing is configured, the local router sets the next hop of outbound routes for a peer/peer group to itself regardless of whether the peer next-hop-local command is configured.

l In a special networking environment of third-party next hop (that is, a broadcast network with two BGP4+ peers connected to the same network segment), by default, the router does not use its own address as the next hop when advertising routes to EBGP peers/peer groups; the router uses its own address as the next hop only after the peer next-hop-local command is used.

5.5.3 Configuring the MED Attribute

To configure the MED attribute, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure a default MED value	default med med-value	Optional Defaults to 0
Enable to compare MED values of routes from different EBGP peers	compare-different-as-med	Optional Not enabled by default
Prioritize MED values of routes from each AS	bestroute compare-med	Optional Not configured by default
Prioritize MED values of routes from confederation peers	bestroute med-confederation	Optional Not configured by default

5.5.4 Configuring the AS_PATH Attribute

To do so, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Allow local AS number in AS_PATH of routes from a peer/peer group	peer { ipv6-group-name \| ipv6-address } allow-as-loop [ number ]	Optional Not allowed by default
Specify a fake AS number for a peer/peer group	peer { ipv6-group-name \| ipv6-address } fake-as as-number	Optional Not specified by default
Neglect the AS_PATH attribute for best route selection	bestroute as-path-neglect	Optional Not neglected by default
Configure to carry only the public AS number in updates sent to a peer/peer group	peer { ipv6-group-name \| ipv6-address } public-as-only	Optional By default, BGP updates carry private AS number
Substitute local AS number for the AS number of a peer/peer group indicated in the AS_PATH attribute	peer { ipv6-group-name \| ipv6-address } substitute-as	Optional Not substituted by default

5.6 Adjusting and Optimizing BGP4+ Networks

This section describes configurations of BGP4+ timers, BGP4+ connection soft reset and the maximum number of load balancing routes.

1) BGP4+ timers

After establishing a BGP4+ connection, two routers send keepalive messages periodically to each other to keep the connection. If a router receives no keepalive message from the peer after the holdtime elapses, it tears down the connection.

When establishing a BGP4+ connection, the two parties compare their holdtime values, taking the shorter one as the common holdtime. If the holdtime is 0, neither keepalive massage is sent, nor holdtime is checked.

2) BGP4+ connection soft reset

After modifying a route selection policy, you have to reset BGP4+ connections to make the new one take effect, causing a short time disconnection. The current BGP4+ implementation supports the route-refresh feature that enables dynamic BGP4+ routing table refresh without needing to disconnect BGP4+ links.

With this feature enabled on all BGP4+ routers in a network, when a routing policy modified on a router, the router advertises a route-refresh message to its peers, which then send their routing information back to the router. Therefore, the local router can perform dynamic routing information update and apply the new policy without tearing down connections.

If a router not supporting route-refresh exists in the network, you need to configure the peer keep-all-routes command on the router to save all route updates, and then use the refresh bgp ipv6 command to soft-reset BGP4+ connections.

5.6.1 Prerequisites

Before configuring BGP4+ timers, you have:

l Enabled IPv6 function

l Configured BGP4+ basic functions

5.6.2 Configuring BGP4+ Timers

To do so, use the following commands:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter BGP view		bgp as-number	Required
Enter IPv6 address family view		ipv6-family	—
Configure BGP4+ timers	Specify keepalive interval and holdtime	timer keepalive keepalive hold holdtime	Optional The keepalive interval defaults to 60 seconds, holdtime defaults to 180 seconds.
Configure BGP4+ timers	Configure keepalive interval and holdtime for a peer/peer group	peer { ipv6-group-name \| ipv6-address } timer keepalive keepalive hold holdtime
Configure the interval for sending the same update to a peer/peer group		peer { ipv6-group-name \| ipv6-address } route-update-interval seconds	Optional The interval for sending the same update to an IBGP peer or an EBGP peer defaults to 15 seconds or 30 seconds

& Note:

l Timers configured using the timer command have lower priority than timers configured using the peer timer command.

l The holdtime interval must be at least three times the keepalive interval.

5.6.3 Configuring BGP4+ Soft Reset

I. Enable route refresh

To enable route refresh, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Enable route refresh	peer { ipv6-group-name \| ipv6-address } capability-advertise route-refresh	Optional Enabled by default

II. Perform manual soft-reset

To perform manual soft reset, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Save all routes from a peer/peer group, not letting them go through the inbound policy	peer { ipv6-group-name \| ipv6-address } keep-all-routes	Optional Not saved by default.
Return to user view	return	—
Soft-reset BGP4+ connections manually	refresh bgp ipv6 { all \| ipv6-address \| group ipv6-group-name \| external \| internal } { export \| import }	Required

& Note:

If the peer keep-all-routes command is used, all routes from the peer/peer group will be saved regardless of whether filtering policy available. These routes will be used to generate BGP4+ routes after soft-reset is performed.

5.6.4 Configuring the Maximum Number of Load-Balancing Routes

To configure the maximum number of load balancing routes, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure the maximum number of load balancing routes	balance number	Required By default, no load balancing is enabled.

5.7 Configuring a Large Scale BGP4+ Network

For easy management and streamlined configurations, an administrator can allocate the BGP4+ peers having the same update policy to the same logical organization. Such organizations are known as peer groups. A policy configured for a peer group applies to all the members in the group.

Each time the configuration of the peer group changes, the configuration of each group member changes accordingly. You may, however, configure certain attributes for a certain member by specifying its IPv6 address so that the member is not subject to the peer group’s configuration in terms of these attributes.

Normally, the peers in the same AS are configured as a peer group. You can also add the peers of other ASs to the group. All the IBGP peers can be configured as another peer group. Peer groups are created according to service logic.

A peer group allows a group of peers to share the same policy, while a community allows a group of BGP4+ routers in multiple ASs to share the same policy. Community is a route attribute propagated among BGP4+ peers and not restricted by ASs.

To guarantee connectivity between IBGP peers, you need to make them fully meshed, but it becomes unpractical when there are too many IBGP peers. Using router reflector or confederation can solve it. In a large-scale AS, both of them can be used.

Confederation configuration of BGP4+ is identical to that of BGP, so it is not mentioned here. The following describes:

l Configuring BGP4+ peer group

l Configuring BGP4+ community

l Configuring BGP4+ router reflector

5.7.1 Prerequisites

Before configuring BGP4+ peer group, you have:

l Made peer nodes accessible at network layer

l Enabled BGP and configured router ID.

5.7.2 Configuring BGP4+ Peer Group

I. Create an IBGP peer group

To create an IBGP group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required Not enabled by default
Enter IPv6 address family view	ipv6-family	—
Create an IBGP peer group	group ipv6-group-name [ internal ]	Required
Add a peer into the group	peer ipv6-address group ipv6-group-name [ as-number as-number ]	Required Not added by default

II. Create a pure EBGP peer group

To configure a pure EBGP group, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required Not enabled by default
Enter IPv6 address family view	ipv6-family	—
Create an EBGP peer group	group ipv6-group-name external	Required
Configure the AS number for the peer group	peer ipv6-group-name as-number as-number	Required Not configured by default
Add an IPv6 peer into the peer group	peer ipv6-address group ipv6-group-name	Required Not added by default

& Note:

l To create a pure EBGP peer group, you need to specify the AS number for the peer group.

l If a peer was added into an EBGP peer group, you cannot specify any AS number for the peer group.

III. Create a mixed EBGP peer group

To do so, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required Not enabled by default
Enter IPv6 address family view	ipv6-family	—
Create an EBGP peer group	group ipv6-group-name external	Required
Specify the AS number of an IPv6 peer	peer ipv6-address as-number as-number	Required Not specified by default
Add the IPv6 peer into the peer group	peer ipv6-address group ipv6-group-name	Required Not added by default

& Note:

When creating a mixed EBGP peer group, you need to create a peer and specify its AS number that can be different from AS numbers of other peers, but you cannot specify any AS number for the EBGP peer group.

5.7.3 Configuring BGP4+ Community

I. Advertise community attribute to a peer/peer group

To do so, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required Not enabled by default
Enter IPv6 address family view	ipv6-family	—
Advertise community attribute to a peer/peer group	peer { ipv6-group-name \| ipv6-address } advertise-community	Required Not advertised by default

II. Apply a routing policy to routes advertised to a peer/peer group

To do so, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Apply a routing policy to routes advertised to a peer/peer group	peer { ipv6-group-name \| ipv6-address } route-policy route-policy-name export	Required Not applied by default

& Note:

l When configuring BGP4+ community, you need to configure a routing policy to define the community attribute, and apply the routing policy to route advertisement.

l For routing policy configuration, refer to Chapter 6 Routing Policy Configuration .

5.7.4 Configuring a BGP4+ Router Reflector

To configure a BGP4+ router reflector, use the following commands:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	Required
Enter IPv6 address family view	ipv6-family	—
Configure the router as a router reflector and specify a peer/peer group as a client	peer { ipv6-group-name \| ipv6-address } reflect-client	Required Not configured by default
Enable route reflection between clients	reflect between-clients	Optional Enabled by default
Configure the cluster ID of the router reflector	reflector cluster-id cluster-id	Optional By default, a router reflector uses its router ID as the cluster ID

& Note:

l In general, it is not required to make clients of a router reflector fully meshed. The router reflector forwards routing information between clients. If clients are fully meshed, you can disable route reflection between clients to reduce metrics.

l If a cluster has multiple router reflectors, you need to specify the same cluster ID for these router reflectors to avoid routing loops.

5.8 Displaying and Maintaining BGP4+ Configuration

5.8.1 Displaying BGP

To do…	Use the command…	Remarks
Display peer group information	display bgp ipv6 group [ ipv6-group-name ]	Available in any view
Display BGP4+ advertised routing information	display bgp ipv6 network
Display AS path information	display bgp ipv6 paths [ as-regular-expression ]
Display BGP peer information	display bgp ipv6 peer [ ipv6-address { log-info \| verbose } \| ipv6-group-name log-info \| verbose ]
Display BGP4+ routing table information	display bgp ipv6 routing-table [ ipv6-address prefix-length ]
Display routing information matched by a AS path ACL	display bgp ipv6 routing-table as-path-acl as-path-acl-number
Display BGP4+ community routing information	display bgp ipv6 routing-table community [ aa:nn<1-13> ] [ no-advertise \| no-export \| no-export-subconfed ]* [ whole-match ]
Display routing information matched by a BGP4+ community list	display bgp ipv6 routing-table community-list { basic-community-list-number [ whole-match ] \| adv-community-list-number }&<1-16>
Display BGP4+ dampened routing information	display bgp ipv6 routing-table dampened
Display BGP4+ dampening parameter information	display bgp ipv6 routing-table dampening parameter
Display routing information originated from different ASs	display bgp ipv6 routing-table different-origin-as
Display routing flap statistics	display bgp ipv6 routing-table flap-info [ regular-expression as-regular-expression \| as-path-acl as-path-acl-number \| network-address [ prefix-length [ longer-match ] ] ]
Display routing information sent to/received from a peer	display bgp ipv6 routing-table peer ipv6-address { advertised-routes \| received-routes } [ network-address prefix-length \| statistic ]
Display routing information matched by a regular expression	display bgp ipv6 routing-table regular-expression as-regular-expression
Display BGP4+ routing statistics	display bgp ipv6 routing-table statistic

5.8.2 Resetting BGP4+ Connections

To do…	Use the command…	Remarks
Reset all BGP4+ connections	reset bgp ipv6 all	Available in user view
Reset the BGP4+ connection to an AS	reset bgp ipv6 as-number
Reset the BGP4+ connection to a peer	reset bgp ipv6 ipv6-address [ flap-info ]
Reset all EBGP connections	reset bgp ipv6 external
Reset the BGP4+ connection to a peer group	reset bgp ipv6 group ipv6-group-name
Reset all IBGP connections	reset bgp ipv6 internal

5.8.3 Clearing BGP4+ Information

To do…	Use the command…	Remarks
Clear dampening routing information and release suppressed routes	reset bgp ipv6 dampening [ ipv6-address prefix-length ]	Available in user view
Clear route flap information	reset bgp ipv6 flap-info [ ipv6-address/prefix-length \| regexp as-path-regexp \| as-path-acl as-path-acl-number ]	Available in user view

5.9 BGP4+ Configuration Examples

& Note:

Some BGP4+ configuration examples are similar to those of BGP4, so refer to BGP Configuration in IPv4 Routing for related information.

5.9.1 BGP4+ Basic Configuration

I. Network requirements

In Figure 5-1 are all BGP4+ switches. Between Switch A and Switch B is an EBGP connection. Switch B, Switch C and Switch D are IBGP fully meshed.

II. Network diagram

Figure 5-1 BGP4+ basic configuration network diagram

III. Configuration procedure

1) Configure IPv6 addresses for interfaces (omitted)

2) Configure IBGP connections

# Configure Switch B.

<SwitchB> system-view

[SwitchB] ipv6

[SwitchB] bgp 65009

[SwitchB-bgp] router-id 2.2.2.2

[SwitchB-bgp] ipv6-family

[SwitchB-bgp-af-ipv6] peer 9:1::2 as-number 65009

[SwitchB-bgp-af-ipv6] peer 9:3::2 as-number 65009

[SwitchB-bgp-af-ipv6] quit

[SwitchB-bgp] quit

# Configure Switch C.

<SwitchC> system-view

[SwitchC] ipv6

[SwitchC] bgp 65009

[SwitchC-bgp] router-id 3.3.3.3

[SwitchC-bgp] ipv6-family

[SwitchC-bgp-af-ipv6] peer 9:3::1 as-number 65009

[SwitchC-bgp-af-ipv6] peer 9:2::2 as-number 65009

[SwitchC-bgp-af-ipv6] quit

[SwitchC-bgp] quit

# Configure Switch D.

<SwitchD> system-view

[SwitchD] ipv6

[SwitchD] bgp 65009

[SwitchD-bgp] router-id 4.4.4.4

[SwitchD-bgp] ipv6-family

[SwitchD-bgp-af-ipv6] peer 9:1::1 as-number 65009

[SwitchD-bgp-af-ipv6] peer 9:2::1 as-number 65009

[SwitchD-bgp-af-ipv6] quit

[SwitchD-bgp] quit

3) Configure the EBGP connection

# Configure Switch A.

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] bgp 65008

[SwitchA-bgp] router-id 1.1.1.1

[SwitchA-bgp] ipv6-family

[SwitchA-bgp-af-ipv6] peer 10::1 as-number 65009

[SwitchA-bgp-af-ipv6] quit

[SwitchA-bgp] quit

# Configure Switch B.

[SwitchB] bgp 65009

[SwitchB-bgp] ipv6-family

[SwitchB-bgp-af-ipv6] peer 10::2 as-number 65008

# Display IPv6 peer information on Switch B.

[SwitchB] display bgp ipv6 peer

BGP local router ID : 2.2.2.2

Local AS number : 65009

Total number of peers : 3 Peers in established state : 3

Peer V AS MsgRcvd MsgSent OutQ PrefRcv Up/Down State

10::2 4 65008 3 3 0 0 00:01:16 Established

9:3::2 4 65009 2 3 0 0 00:00:40 Established

9:1::2 4 65009 2 4 0 0 00:00:19 Established

# Display IPv6 peer information on Switch C.

[SwitchC] display bgp ipv6 peer

BGP local router ID : 3.3.3.3

Local AS number : 65009

Total number of peers : 2 Peers in established state : 2

Peer V AS MsgRcvd MsgSent OutQ PrefRcv Up/Down State

9:3::1 4 65009 4 4 0 0 00:02:18 Established

9:2::2 4 65009 4 5 0 0 00:01:52 Established

Switch A and B established an EBGP connection; Switch B, C and D established IBGP connections with each other.

5.9.2 BGP4+ Router Reflector Configuration

I. Network requirements

Switch B receives an EBGP update and sends it to Switch C, which is configured as a router reflector with two clients: Switch B and Switch D.

Switch B and Switch D need not establish an IBGP connection because Switch C reflects updates between them.

II. Network diagram

Figure 5-2 BGP4+ router reflector configuration network diagram

III. Configuration procedure

1) Configure IPv6 addresses for VLAN interfaces (omitted)

2) Configure BGP4+ basic functions

# Configure Switch A.

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] bgp 100

[SwitchA-bgp] router-id 1.1.1.1

[SwitchA-bgp] ipv6-family

[SwitchA-bgp-af-ipv6] peer 100::2 as-number 200

[SwitchA-bgp-af-ipv6] network 1:: 64

[SwitchA-bgp-af-ipv6] quit

#Configure Switch B.

<SwitchB> system-view

[SwitchB] ipv6

[SwitchB] bgp 200

[SwitchB-bgp] router-id 2.2.2.2

[SwitchB-bgp] ipv6-family

[SwitchB-bgp-af-ipv6] peer 100::1 as-number 100

[SwitchB-bgp-af-ipv6] peer 101::1 as-number 200

# Configure Switch C.

<SwitchC> system-view

[SwitchC] ipv6

[SwitchC] bgp 200

[SwitchC-bgp] router-id 3.3.3.3

[SwitchC-bgp] ipv6-family

[SwitchC-bgp-af-ipv6] peer 101::2 as-number 200

[SwitchC-bgp-af-ipv6] peer 102::2 as-number 200

# Configure Switch D.

<SwitchD> system-view

[SwitchD] ipv6

[SwitchD] bgp 200

[SwitchD-bgp] router-id 4.4.4.4

[SwitchD-bgp] ipv6-family

[SwitchD-bgp-af-ipv6] peer 102::1 as-number 200

3) Configure router reflector

# Configure Switch C as a router reflector, Switch B and Switch D as its clients.

[SwitchC-bgp-af-ipv6] peer 101::2 reflect-client

[SwitchC-bgp-af-ipv6] peer 102::2 reflect-client

Use the display bgp ipv6 routing-table command on Switch B and Switch D respectively, you can find both of them have learned the network 1::/64.

5.10 Troubleshooting BGP4+ Configuration

5.10.1 No BGP4+ Peer Relationship Established

I. Symptom

Display BGP4+ peer information using the display bgp ipv6 peer command. The state of the connection to the peer cannot become established.

II. Analysis

To become BGP4+ peers, any two routers need to establish a TCP session using port 179 and exchange open messages successfully.

III. Processing steps

1) Use the display current-configuration command to verify the peer’s AS number.

2) Use the display bgp ipv6 peer command to verify the peer’s IPv6 address.

3) If the loopback interface is used, check whether the peer connect-interface command is configured.

4) If the peer is not directly connected, check whether the peer ebgp-max-hop command is configured.

5) Check whether a route to the peer is available in the routing table.

6) Use the ping command to check connectivity.

7) Use the display tcp status command to check the TCP connection.

8) Check whether an ACL for disabling TCP port 179 is configured.

Chapter 6 Routing Policy Configuration

& Note:

l Verify that the system already operates in IPv4/IPv6 dual-stack mode before configuring IPv6 routing policy.

l All the IPv6 routing policy related configuration mentioned in this manual assumes that the system already operates in IPv4/IPv6 dual-stack mode. For dual stack mode configuration, see the part covering dual stack in the IPv6 Configuration module.

A routing policy is used on the router for route inspection, filtering, attributes modifying when routes are received, advertised, or redistributed.

6.1 Introduction to Routing Policy

6.1.1 Routing Policy and Policy Routing

By modifying route attributes (including reachability), routing policy is adopted to change routing path for network traffic.

When distributing or receiving routing information, a router can apply some policy to filter routing information, for example, a router handles only routing information that matches some rules, or a routing protocol redistributes from other protocols only routes matching some rules and modifies some attributes of these routes to satisfy its needs.

To implement routing policy, first define the features of routing information, namely, a set of matching rules. You can make definitions according to attributes in routing information, such as destination address, advertising router’s address. The matching rules can be set beforehand and then apply them to a routing policy for route distribution, reception and redistribution.

6.1.2 Filters

Routing protocols can use five filters: ACL, IP prefix list, AS path, community-list and route policy.

I. ACL

When defining an ACL, you can specify IP addresses and prefixes for matching destinations or next hops of routing information.

For ACL configuration, refer to ACL Operation manual.

II. IP prefix list

IP-prefix list plays a role similar to ACL, but it is more flexible than ACL and easier to understand. When IP-prefix list is applied for routing information filtering, its matching object is the destination address information field of routing information.

An IP-prefix list is identified by the IP-prefix list name. Each IP-prefix list can comprise multiple items, and each item, which is identified by an index number, can specify a matching range in network prefix format. The index number indicates the matching sequence in the IP-prefix list.

During matching, a router checks list items identified by index number in the ascending order. If one item matched, the IP-prefix list filtering is passed, without needing to match the next item.

III. AS-path ACL

AS-path ACL only applies to BGP4+. There is an AS-path field in the BGP4+ routing information packets. As-path-acl specifies matching conditions according to the AS-path field.

IV. Community list

The community list only applies to BGP4+. The BGP4+ routing information packet contains a community attribute field to identify a community. Based on the community attribute, the community-list specifies matching conditions.

V. Routing policy

A routing policy is used for matching some attributes in given routing information and modifying the attributes of the information if matching conditions are satisfied. A routing policy can utilize the above filters to define its own matching rules.

A routing policy can comprise multiple nodes, which are in logic OR relationship. Each node is a matching unit, and the system checks nodes in the order of node sequence number. Once the matching test of a node is passed, the route-policy is passed without needing to match other nodes.

Each node comprises a set of if-match and apply clauses. The if-match clauses define the matching rules. The matching objects are some attributes of routing information. The different if-match clauses on the same node is in logic AND relationship. Only when the matching conditions specified by all the if-match clauses on a node are satisfied, can routing information passes the matching test of the node. The apply clauses specify the actions performed after the node matching test passed, concerning the attribute settings for the routing information.

6.1.3 Routing Policy Application

Routing policy applies in two ways:

l When redistributing routes from other routing protocols, a routing protocol redistributes only routes matching rules defined in a routing policy.

l When receiving or advertising routing information, a routing protocol uses a routing policy to filter routing information.

6.2 Defining Filtering Lists

6.2.1 Prerequisites

Before configuring this task, prepare the following data:

l IP-prefix list name

l Matching address range

6.2.2 Defining an IPv6-prefix List

Identified by name, each IPv6 prefix list can comprise multiple items. Each item specifies a matching address range in the form of network prefix, which is identified by index number.

During matching, the system checks list items identified by index number in the ascending order. If one item is matched, IP-prefix list filtering is passed, without needing to match other items.

To define an IPv6 prefix list, use the following commands:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Define an IPv6 prefix list

ip ipv6-prefix ipv6-prefix-name [ index index-number ] { deny | permit } ipv6-address prefix-length [ greater-equal min-prefix-length ] [ less-equal max-prefix-length ]

Required

Not defined by default

& Note:

If all items are set to the deny mode, no route can pass the IPv6 prefix list. It is recommended to define the permit :: 0 less-equal 128 item following multiple deny mode items to allow other IPv6 routing information to pass.

For example, the following configuration filters routes 2000:1::/48, 2000:2::/48 and 2000:3::/48, but allows other routes to pass.

<Sysname> system-view

[Sysname] ip ipv6-prefix abc index 10 deny 2000:1:: 48

[Sysname] ip ipv6-prefix abc index 20 deny 2000:2:: 48

[Sysname] ip ipv6-prefix abc index 30 deny 2000:3:: 48

[Sysname] ip ipv6-prefix abc index 40 permit :: 0 less-equal 128

6.2.3 Defining an AS Path ACL

You can define multiple items for an AS path ACL that is identified by its number. During matching, the relation between items is logic OR, that is, if routing information matches one of these items, it passes the AS path ACL.

To define an AS path ACL, use the following commands:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Define an AS path ACL

ip as-path-acl as-path-acl-number { deny | permit } regular-expression

Required

Not defined by default

6.2.4 Defining a Community List

You can define multiple items for a community list that is identified by its number. During matching, the relation between items is logic OR, that is, if routing information matches one of these items, it passes the community list.

To define a community list, use the following commands:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Define a community list	Define a basic community list	ip community-list basic-comm-list-num { deny \| permit } [ community-number-list ] [ internet \| no-advertise \| no-export \| no-export-subconfed ]*	Required to define either Not defined by default
Define a community list	Define an advanced community list	ip community-list adv-comm-filter-num { deny \| permit } regular-expression	Required to define either Not defined by default

6.3 Configuring a Routing Policy

A routing policy is used to filter routing information according to some attributes, and modify some attributes of the routing information that matches the routing policy. Matching rules can be configured using filters above mentioned.

A routing policy can comprise multiple nodes, each node contains:

l if-match clauses: define the matching rules routing information must satisfy. The matching objects are some attributes of routing information.

l apply clauses: specifies the actions performed after specified matching rules satisfied, concerning attribute settings for passed routing information.

6.3.1 Prerequisites

Before configuring this task, you have completed:

l Filtering list configuration

l Routing protocol configuration

You also need to decide on:

l Name of routing policy, node sequence numbers

l Matching rules

l Attributes to be modified

6.3.2 Creating a Routing Policy

To create a routing policy, use the following commands:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Create a routing policy and enter its view

route-policy route-policy-name { permit | deny } node node-number

Required

Not created by default

& Note:

l If a node is specified as permit, routing information meeting the node’s conditions will be handled using the apply clauses of this node, without needing to match the next node. If routing information does not meet the node’s conditions, it will go to the next node for matching.

l If a node is specified as deny, the apply clauses of the node will not be executed. When routing information meets all if-match clauses, it cannot pass the node, nor can it go to the next node. If route information cannot meet any if-match clause of the node, it will go to the next node for matching.

l When a routing policy is defined with more than one node, at least one node should be configured using the permit keyword. If the routing policy is used to filter routing information, routing information that does not meet any node’s conditions cannot pass the routing policy. If all nodes of the routing policy are set using the deny keyword, no routing information can pass it.

6.3.3 Defining if-match Clauses for the Routing Policy

To define if-match clauses for a route-policy, use the following command:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter routing policy view	route-policy route-policy-name { permit \| deny } node node-number	Required
Set conditions to match IPv6 routing information	if-match ipv6 { address \| next-hop \| route-source } { acl acl-number \| prefix-list ipv6-prefix-name }	Optional Not configured by default
Set conditions to match AS path field of BGP4+ routing information	if-match as-path as-path-acl-number&<1-16>	Optional Not configured by default
Match community attribute of BGP4+ routing information	if-match community { basic-community-list-number [ whole-match ] \| adv-community-list-number }&<1-16>	Optional Not configured by default
Match route cost of routing information	if-match cost value	Optional Not configured by default
Match outbound interface of routing information	if-match interface { interface-type interface-number }&<1-16>	Optional Not configured by default
Match types of routes	if-match route-type { internal \| external-type1 \| external-type2 \| external-type1or2 \| is-is-level-1 \| is-is-level-2 \| nssa-external-type1 \| nssa-external-type2 \| nssa-external-type1or2 }*	Optional Not configured by default
Configure the matching condition for the tag field of the routing information	if-match tag value	Optional Not configured by default

& Note:

l The if-match clauses of a route-policy are in logic AND relationship, namely, routing information has to satisfy all if-match clauses before executed with apply clauses.

l You can specify no or multiple if-match clauses for a routing policy. If no if-match clause is specified, and the routing policy is in permit mode, all routing information can pass the node, or in deny mode, no routing information can pass.

6.3.4 Defining apply Clauses for the Routing Policy

To define apply clauses for a route-policy, use the following command:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a routing policy and enter its view	route-policy route-policy-name { permit \| deny } node node-number	Required Not created by default
Set AS_PATH of BGP4+ routing information	apply as-path as-number&<1-10> [ replace ]	Optional Not set by default
Specify a community list according to which to delete community attributes of BGP4+ routing information	apply comm-list comm-list-number delete	Optional Not configured by default
Set community attribute of BGP4+ routing information	apply community { none \| additive \| { community-number&<1-16> \| aa:nn&<1-16> \| no-export-subconfed \| no-export \| no-advertise }* [ additive ] }	Optional Not set by default
Set the cost of routing information	apply cost [ + \| - ] value	Optional Not set by default
Set the cost type of routing information	apply cost-type { external \| internal \| type-1 \| type-2 }	Optional Not set by default
Set the next hop for IPv6 routing information	apply ipv6 next-hop ipv6-address	Optional Not set by default
Redistribute routes to a specified ISIS level	apply isis { level-1 \| level-1-2 \| level-2 }	Optional Not configured by default
Set the local preference of BGP4+ routing information	apply local-preference preference	Optional Not set by default
Set origin attributes of BGP4+ routing information	apply origin { igp \| egp as-number \| incomplete }	Optional Not set by default
Set routing protocol preference	apply preference preference	Optional Not set by default
Set the preferred value of BGP routing information	apply preferred-value preferred-value	Optional Not set by default
Set the tag field of routing information	apply tag value	Optional Not set by default

& Note:

The apply ipv6 next-hop commands do not apply to redistributed IPv6 routes.

6.4 Displaying and Maintaining the Routing Policy

To do…	Use the command…	Remarks
Display BGP4+ AS path ACL information	display ip as-path-acl [ as-path-acl-number ]	Available in any view
Display BGP4+ community list information	display ip community-list [ basic-community-list-number \| adv-community-list-number ]
Display IPv6 prefix list statistics	display ip ipv6-prefix [ ipv6-prefix-name ]
Display routing policy information	display route-policy [ route-policy-name ]
Clear IPv6 prefix statistics	reset ip ipv6-prefix [ ipv6-prefix-name ]	Available in user view

6.5 Routing Policy Configuration Example

6.5.1 Applying Routing Policy When Redistributing IPv6 Routes

I. Network requirements

l Enable RIPng and configure three static routes on Switch A.

l Apply a routing policy when redistributing static routes, making routes in 20::0/32 and 40::0/32 pass, routes in 30::0/32 filtered.

l Display RIPng routing table information on Switch B to verify the configuration.

II. Network diagram

Figure 6-1 Network diagram for routing policy application to route redistribution

III. Configuration procedure

1) Configure Switch A.

# Configure IPv6 addresses for Vlan-interface 100 and Vlan-interface 200.

<SwitchA> system-view

[SwitchA] ipv6

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ipv6 address 10::1 32

[SwitchA-Vlan-interface100] quit

[SwitchA] interface vlan-interface 200

[SwitchA-Vlan-interface200] ipv6 address 11::1 32

[SwitchA-Vlan-interface200] quit

# Enable RIPng on Vlan-interface 100.

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ripng 1 enable

[SwitchA-Vlan-interface100] quit

# Configure three static routes.

[SwitchA] ipv6 route-static 20:: 32 11::2

[SwitchA] ipv6 route-static 30:: 32 11::2

[SwitchA] ipv6 route-static 40:: 32 11::2

# Configure routing policy.

[SwitchA] ip ipv6-prefix a index 10 permit 30:: 32

[SwitchA] route-policy static2ripng deny node 0

[SwitchA-route-policy] if-match ipv6 address prefix-list a

[SwitchA-route-policy] quit

[SwitchA] route-policy static2ripng permit node 10

[SwitchA-route-policy] quit

# Enable RIPng and redistribute static routes.

[SwitchA] ripng

[SwitchA-ripng-1] import-route static route-policy static2ripng

2) Configure Switch B.

# Configure the IPv6 address for Vlan-interface 100.

[SwitchB] ipv6

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ipv6 address 10::2 32

# Enable RIPng on Vlan-interface 100.

[SwitchB-Vlan-interface100] ripng 1 enable

[SwitchB-Vlan-interface100] quit

# Enable RIPng.

[SwitchB] ripng

# Display RIPng routing table information.

[SwitchB-ripng-1] display ripng 1 route

Route Flags: A - Aging, S - Suppressed, G - Garbage-collect

----------------------------------------------------------------

Peer FE80::7D58:0:CA03:1 on Vlan-interface 100

Dest 10::/32,

via FE80::7D58:0:CA03:1, cost 1, tag 0, A, 18 Sec

Dest 20::/32,

via FE80::7D58:0:CA03:1, cost 1, tag 0, A, 8 Sec

Dest 40::/32,

via FE80::7D58:0:CA03:1, cost 1, tag 0, A, 3 Sec

6.6 Troubleshooting Routing Policy Configuration

6.6.1 IPv6 Routing Information Filtering Failed

I. Symptom

Filtering routing information failed, while routing protocol runs normally.

II. Analysis

At least one item of the IPv6 prefix list should be configured as permit mode, and at least one node of the Route-policy should be configured as permit mode.

III. Processing procedure

1) Use the display ip ipv6-prefix command to display IP prefix list.

2) Use the display route-policy command to display route policy information.

H3C S3610[5510] Series Ethernet Switches Operation Manual-Release 0001-(V1.02)

1.1 Introduction to IPv6 Static Routing

1.2 Configuring IPv6 Static Routes

1.3 Displaying and Maintaining IPv6 Static Routes

1.4 IPv6 Static Routing Configuration Example

I. Network requirements

II. Network diagram

III. Configuration procedure

Chapter 2 IPv6-RIPng Configuration

2.1 Introduction to RIPng

2.1.1 RIPng Working Mechanism

2.1.2 RIPng Packet Format

I. Basic format

II. RTE format

I. Request packet

II. Response packet

2.2 RIPng Basic Configuration

2.3 RIPng Configuration

2.3.1 Configuring an Additional Routing Metric

2.3.2 Configuring RIPng Route Summarization

2.3.3 Configuring RIPng to Advertise a Default Route

2.3.4 Configuring a RIPng Route Filtering Policy

2.3.5 Configuring a RIPng Priority

2.3.6 Configuring RIPng Route Redistribution

2.4 RIPng Network Adjustment and Optimization

2.4.1 Configuring RIPng Timers

2.4.2 Configuring the Split Horizon and Poison Reverse Functions

I. Configure the split horizon function

II. Configuring the poison reverse function

2.4.3 Configuring Zero Field Check for RIPng Packet Headers

2.6 RIPng Configuration Example

I. Network requirements

II. Network diagram

III. Configuration procedure

Chapter 3 IPv6-OSPFv3 Configuration

3.1 Introduction to OSPFv3

I. OSPFv3 packet timer

II. LSA delay time

III. SPF timer

3.2 IPv6-OSPFv3 Configuration Task List

3.3 Configuring OSPFv3 Basic Functions

3.3.1 Prerequisites

3.4 Configuring OSPFv3 Area Parameters

3.4.2 Configuring an OSPFv3 Stub Area

3.4.3 Configuring OSPFv3 Virtual Links

3.5 Configuring OSPFv3 Routing Information Management

3.5.2 Configuring OSPFv3 Route Summarization

3.5.3 Configuring OSPFv3 Inbound Route Filtering

3.5.4 Configuring Link Costs for OSPFv3 Interfaces

3.5.5 Configuring the Maximum Number of OSPFv3 Load-balancing Routes

3.5.6 Configuring OSPFv3 Route Redistribution

3.6 Configuring OSPFv3 Network Optimization

3.6.2 Configuring OSPFv3 Timers

3.6.3 Configuring the DR Priority for an Interface

3.6.4 Ignoring MTU Check for DD Packets

3.6.5 Disable Interfaces from Sending OSPFv3 Packets

3.7 Displaying and Maintaining OSPFv3

3.8 OSPFv3 Configuration Examples

I. Network requirements

II. Network diagram

III. Configuration procedure

I. Network requirements

II. Network diagram

III. Configuration procedure

I. Symptom

II. Analysis

III. Process steps

I. Symptom

II. Analysis

III. Process steps

Chapter 4 IPv6-IS-IS Configuration

4.2 IPv6-IS-IS Basic Configuration

4.3 Configuring IPv6-IS-IS Routing Information Control

4.4 Displaying and Maintaining IPv6-IS-IS

4.5 IPv6-IS-IS Configuration Example

I. Network requirements

II. Network diagram

III. Configuration procedure

5.1 BGP4+ Overview

5.3 Configuring BGP4+ Basic Functions