Table of Contents

Chapter 1 Static Routing Configuration. 1-1

1.1 Introduction. 1-1

1.1.1 Static Routing. 1-1

1.1.2 Default Routes. 1-1

1.1.3 Application of Static Routing. 1-1

1.2 Configuring Static Route. 1-2

1.2.1 Configuration Prerequisites. 1-2

1.2.2 Configuring Static Routes. 1-2

1.3 Displaying and Maintaining Static Routes. 1-3

1.4 Example of Static Routes Configuration. 1-4

Chapter 2 RIP Configuration. 2-1

2.1 RIP Overview. 2-1

2.1.1 RIP Mechanism.. 2-1

2.1.2 RIP Version. 2-3

2.1.3 RIP Message Format 2-4

2.1.4 RIP Feature Supported. 2-5

2.1.5 RIP Related RFC. 2-5

2.2 RIP Basic Configuration. 2-6

2.2.1 Configuring RIP Basic Function. 2-6

2.3 RIP Route Control 2-8

2.3.1 Configuring additional routing metric. 2-8

2.3.2 Configuring route summarization. 2-8

2.3.3 Disabling the receiving of host routes. 2-9

2.3.4 Configuring default route. 2-9

2.3.5 Configuring route filtering. 2-10

2.3.6 Configuring protocol priority. 2-10

2.3.7 Redistributing route. 2-10

2.4 RIP Configuration Optimization. 2-11

2.4.1 Configuring RIP timer 2-11

2.4.2 Configuring split horizon and poison reverse. 2-12

2.4.3 Configuring RIP updating message validation. 2-12

2.4.4 Configuring RIP-2 message authentication. 2-13

2.4.5 Configuring RIP peer 2-13

2.5 Displaying and Maintaining RIP. 2-14

2.6 RIP Configuration Example. 2-15

2.6.1 Configuring RIP Version. 2-15

2.7 Troubleshooting RIP Configuration. 2-17

Chapter 3 Routing Policy Configuration. 3-1

3.1 Introduction to Routing Policy. 3-1

3.1.1 Routing Policy. 3-1

3.1.2 Filters. 3-1

3.1.3 Routing Policy Application. 3-2

3.2 Defining IPv4 Prefix List 3-2

3.3 Configuring a Routing Policy. 3-3

3.3.1 Creating a Routing Policy. 3-4

3.3.2 Defining if-match Clauses for the Routing Policy. 3-4

3.3.3 Defining apply Clauses for the Routing Policy. 3-5

3.4 Displaying and Maintaining the Routing Policy. 3-6

3.5 Routing Policy Configuration Example. 3-6

3.5.1 Applying Routing Policy When Redistributing IPv4 Routes. 3-6

3.6 Troubleshooting Routing Policy Configuration. 3-8

3.6.1 IPv4 Routing Information Filtering Failed. 3-8

 

Chapter 1  Static Routing Configuration

 

 

1.1  Introduction

1.1.1  Static Routing

A static route is a special route that is manually configured by the network administrator. If a network is relatively simple, you only need to configure static routes for the network to work normally. The proper configuration and usage of static routes can improve a network’s performance and ensure bandwidth for important network applications.

The disadvantage of static routing is that, if a fault or a topological change occurs to the network, the route will be unreachable and the network breaks. In this case, the network administrator has to modify the configuration manually.

1.1.2  Default Routes

A default route is a special static route.

Generally, a router selects the default route only when it cannot find any matching entry in the routing table. In a routing table, the default route is in the form of the route to the network 0.0.0.0 (with the mask 0.0.0.0). You can check whether a default route has been configured by running the display ip routing-table command.

If the destination address of a packet fails to match any entry in the routing table, the router selects the default route to forward the packet. If there is no default route and the destination address of the packet is not in the routing table, the packet will be discarded and an ICMP packet is sent to the source reporting that the destination or the network is unreachable.

1.1.3  Application of Static Routing

You need to be familiar with the following contents while configuring static routes:

1)         Destination address and masks

In the ip route-static command, the IPv4 address is in dotted decimal format and the mask can be in either dotted decimal format or the mask length (the digits of consecutive 1s in the mask).

2)         Output interface and the next hop address

While configuring static routes, you can specify either the output interface or next hop address. Whether you should specify the output interface or the next hop address depends on the specific occasion.

In fact, all the route entries must specify the next hop address. While forwarding a packet, the corresponding route is determined by searching the routing table for the packet’s destination address. Only after the next hop address is specified, the corresponding link-layer address can be found for the link-layer to forward the packet.

3)         Other attributes

You can configure different preferences for different static routes for the purpose of easy routing management policy. For example, while configuring multiple routes to the same destination, using identical preference allows for load sharing while using different preference allows for routing backup.

 

 

1.2  Configuring Static Route

1.2.1  Configuration Prerequisites

Before configuring a static route, you need to finish the following tasks:

l           Configuring the physical parameters for relative interfaces

l           Configuring the link-layer attribute for relative interfaces

l           Configuring the IP address for relative interfaces

1.2.2  Configuring Static Routes

Follow these steps to configure a static route:

Operation	Command	Description
Enter system view	system-view	—
Configure a static route	ip route-static ip-address { mask | mask-length } { [ vlan-interface vlan-id ] nexthop-address | NULL interface-number } [ preference preference | description description-info | tag tag-value ]*	Required
Configure the default preference for a static route	ip route-static default-preference default-preference-value	Optional The preference is 60 by default.

 

 

1.3  Displaying and Maintaining Static Routes

After the configuration, you can run the display command in any view to display the running status and configuration effect of the static route configuration.

You can use the delete command in the system view to delete all the static routes configured.

Follow these steps to display and maintain a static route:

Operation	Command
Display the summary of the IP routing table	display ip routing-table
Display the details of the IP routing table	display ip routing-table verbose
Display the information of a static route	display ip routing-table protocol static [ inactive | verbose ]
Delete all static routes	delete static-routes all

 

 

1.4  Example of Static Routes Configuration

I. Network requirements

The switches’ interfaces and the hosts’ IP addresses and masks are shown in the following figure. It requires static routes to connect the hosts for inter-communication.

II. Network diagram

Figure 1-1 Network diagram for static routes

III. Configuration procedure

1)         Configuring the interfaces’ IP addresses

Omitted.

2)         Configuring the static route

# Configure a default route on SwitchA.

<SwitchA> system-view

[SwitchA] ip route-static 0.0.0.0 0.0.0.0 1.1.4.2

# Configure two static routes on SwitchB.

<SwitchB> system-view

[SwitchB] ip route-static 1.1.1.0 255.255.255.0 1.1.4.1

[SwitchB] ip route-static 1.1.3.0 255.255.255.0 1.1.4.6

# Configure a default route on SwitchC.

[Switch B<SwitchC> system-view

[SwitchC] ip route-static 0.0.0.0 0.0.0.0 1.1.4.5

3)         Configure the hosts

The default gateways for the three hosts PC1, PC2 and PC3 are configured as 1.1.1.1, 1.1.2.1 and 1.1.3.1 respectively.

4)         Display the configuration result

# Display the IP route table of SwitchA.

[SwitchA]display ip routing-table

Routing Tables: Public

         Destinations : 7        Routes : 7

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

 

0.0.0.0/0           Static 60   0            1.1.4.2         Vlan100

1.1.1.0/24          Direct 0    0            1.1.1.1         Vlan200

1.1.1.1/32          Direct 0    0            127.0.0.1       InLoop0

1.1.4.0/30          Direct 0    0            1.1.4.1         Vlan100

1.1.4.1/32          Direct 0    0            127.0.0.1       InLoop0

127.0.0.0/8         Direct 0    0            127.0.0.1       InLoop0

127.0.0.1/32        Direct 0    0            127.0.0.1       InLoop0

# Use the ping command to check the connectivity.

[SwitchA] ping 1.1.3.1

  PING 1.1.3.1: 56  data bytes, press CTRL_C to break

    Reply from 1.1.3.1: bytes=56 Sequence=1 ttl=254 time=62 ms

    Reply from 1.1.3.1: bytes=56 Sequence=2 ttl=254 time=63 ms

    Reply from 1.1.3.1: bytes=56 Sequence=3 ttl=254 time=63 ms

    Reply from 1.1.3.1: bytes=56 Sequence=4 ttl=254 time=62 ms

    Reply from 1.1.3.1: bytes=56 Sequence=5 ttl=254 time=62 ms

 

  --- 1.1.3.1 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 62/62/63 ms

 

# Use the tracert command to check the connectivity.

[SwitchA] tracert 1.1.3.1

 traceroute to  1.1.3.1(1.1.3.1) 30 hops max,40 bytes packet, press CTRL_C to break

 1 1.1.4.2 31 ms  32 ms  31 ms

 2 1.1.4.6 62 ms  63 ms  62 ms

 

Chapter 2  RIP Configuration

 

 

2.1  RIP Overview

RIP is a simple Interior Gateway Protocol (IGP), which is mainly used in small-size networks, such as academic networks and simple structured LANs.

RIP is still widely used in practical networking due to its simple implementation, and easier configuration and maintenance than OSPF and IS-IS.

2.1.1  RIP Mechanism

I. Basic concept of RIP

RIP is a distance-vector-based routing protocol, using UDP messages for exchanging information on port 520.

RIP uses a routing metric (Hop Count) to measure the distance to the destination. The Hop Count value of a router to its directly connected network is 0. Networks which are reachable through one other router are one hop etc. To reduce the convergence time, RIP limits the metric value from 0 to 15. It is considered infinity if the value is equal or larger than 16, which means the destination network is unreachable. That is why RIP cannot be used in large scale networks.

RIP prevents routing loops by implementing Split Horizon and Poison Reverse functions.

II. RIP routing table

Each RIP router has a routing table, containing routing entries of all reachable destinations.

l           Destination address: the IP address of a host or a network.

l           Next hop: IP address of the adjacent router to the destination network.

l           Interface: The interface for forwarding

l           Metric: Cost from the local router to the destination

l           Routing time: The amount of time since the entry was last updated. The time is reset to 0 when the routing entry is updated every time.

l           Route change tag: Indicates that the information about this route has changed.

III. RIP timers

RIP uses four timers to control its operation. They are Update, Timeout, Suppress, and Garbage-Collect.

l           Update timer triggers sending new update messages periodically.

l           Timeout timer controls the validity of a route. A route is considered as unreachable when the RIP router does not receive update messages within the aged time from any neighbor.

l           Suppress timer. A route changes to the suppress status when no updated messages are send within the timeout-value or the metric value reaches 16. In the suppress status, the router only accepts update messages with the metric value less than 16 and from the same neighbor to replace the unreachable route.

l           Garbage-Collect timer. The period from the metric value of a route reaches 16 to the route is purged from the table is defined as the garbage collection time in RFC. During the Garbage-Collect time, RIP keeps advertising the route with a metric value of 16. Once the Garbage-Collect time expires and the route is not updated, the route is deleted from the table.

IV. RIP initialization and running procedure

Following procedures describe how RIP works.

1)         After enabling RIP, the router sends Request messages to neighboring routers. Neighboring routers return Response messages including all information about the routing table.

2)         The router updates its local routing table, and broadcasts the routing updates to its neighbors with triggered updating messages. All routers on the network do the same to keep the latest routing table.

In RIP, the routing table on each router is updated upon receipt of RIP messages periodically advertised by neighboring routers. The aged routes are deleted to make sure routes are always valid. The procedure is as follows: RIP periodically advertises the local routing table to neighboring routers, which update their local routes upon receipt of the packets. This procedure repeats on all RIP-enabled routers.

V. Routing loops prevention

RIP is a D-V based routing protocol. Each router calculates the distance to a destination based on the routing information from its neighbors. When a connection to a destination goes down, there is no way for the router on that connection to notify the others about its metric changes. The other routers still use the old routing information to calculate the distance to that destination. Therefore, routing loops can occur in this case.

RIP uses the following mechanisms to prevent routing loops.

l           Counting to infinity. The metric value of 16 is defined as infinity. When a routing loop occurs, the route is considered as unreachable when the metric value reaches 16.

l           Split Horizon. The router does not send the routing table to neighboring routers via the same interface on which it receives. Split Horizon can definitely prevent routing loops and save the bandwidth.

l           Poison Reverse. The router sends routing tables through the same interface from which the tables are received with a metric value of 16 (means infinite). This method can remove useless information in routing tables of neighboring routers.

l           Triggered Updates. Each router sends out its new routing table as long as it receives an update, rather than waiting until the usual update period expires. This can speed up the network convergence.

2.1.2  RIP Version

RIP has two versions: RIP-1 and RIP-2.

RIP-1, a Classful Routing Protocol, supports broadcasting protocol messages. RIP-1 protocol messages do not carry mask information, which means it can only recognize routing information on segments with natural addresses such as Class A, B, and C. That is why RIP-1 does not support routing convergence and Discontiguous Subnet.

RIP-2 is a Classless Routing Protocol. Compared with RIP-1, RIP-2 has the following advantages.

l           Supports Route Tag. The Route Tag is intended to differentiate the internal RIP routes from the external RIP routes.

l           Supports masks, route summarization and CIDR (Classless Inter-Domain Routing).

l           Supports next hop, which must be directly reachable on the broadcast network.

l           Supports multicasting to reduce unnecessary load on hosts that do not need to listen to RIP-2 messages.

l           Supports authentication to enhance security. Plain text authentication and MD5 (Message Digest 5) are two authentication methods.

 

 

2.1.3  RIP Message Format

I. RIP-1 message format

A RIP message consists of Header and Route Entries which can be up to 25.

The format of RIP-1 message is shown in Figure 2-1.

Figure 2-1 RIP-1 Message Format

l           Command: The type of message. 1 indicates Request, 2 indicates Response.

l           Version: The version of RIP. RIP-1 is 0x01.

l           AFI (Address Family Identifier): The family of protocol. 2 is for IP.

l           IP Address: IP address of the destination. Only natural addresses are acceptable here.

l           Metric: The cost of the route.

II. RIP-2 message format

The format of RIP-2 message is similar with RIP-1. Figure 2-2 shows it.

Figure 2-2 RIP-2 Message Format

The differences from RIP-1 are stated as following.

l           Version: The version of RIP. For RIP-2 the value is 0x02.

l           Route Tag: An attribution to indicate from where the routes are imported.

l           IP Address: The destination IP address. It could be a natural address, subnet address or host address.

l           Subnet Mask: Mask of the destination address.

l           Next Hop: The address of the best next hop. 0.0.0.0 indicates that the originator of the route is the best next hop.

III. RIP-2 authentication

RIP-2 supports plain text authentication, which uses the first Route Entry for authentication. The value of 0xFFFF indicates that the entry is authentication information rather than routing information. See Figure 2-3

Figure 2-3 RIP-2 Authentication Message

l           Authentication Type: 2 represents plain text authentication, while 3 represents MD5.

l           Authentication: The actual authentication data. It includes the password information when using plain text authentication.

 

 

2.1.4  RIP Feature Supported

Currently, S5500-SI Series Ethernet Switches support the following RIP features.

l           RIP-1

l           RIP-2

2.1.5  RIP Related RFC

l           RFC 1058: Routing Information Protocol

l           RFC 1723: RIP Version 2 - Carrying Additional Information

l           RFC 1721: RIP Version 2 Protocol Analysis

l           RFC 1722: RIP Version 2 Protocol Applicability Statement

l           RFC 1724: RIP Version 2 MIB Extension

l           RFC 2082: RIP-2 MD5 Authentication

2.2  RIP Basic Configuration

Before configuring RIP features, please first configure IP address on each interface, and make sure all routers are reachable.

2.2.1  Configuring RIP Basic Function

I. Enabling RIP and specify networks

Follow these steps to enable RIP:

Operation	Command	Description
Enter system view	system-view	––
Enable RIP and enter RIP view	rip [ process-id ]	––
Enable RIP on specified network	network network-address	Required Disabled by default

 

 

II. Configuring the interface behavior

Follow these steps to configure interface behavior:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Stop routing updates on interfaces	silent-interface { all | interface-type interface-number }	Optional All interfaces can receive routing updates by default
Return to system view	quit	––
Enter interface view	interface interface-type interface-number	––
Configure an interface to receive routing updates	rip input	Optional By default, the router receives and send RIP messages
Configure an interface to send routing updates	rip output

 

 

III. Configuring the RIP version

Follow these steps to configure the RIP version:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Specify a global RIP version	version { 1 | 2 }	Optional RIP-1 by default
Return to system view	quit	––
Enter interface view	interface interface-type interface-number	––
Specify a RIP version on the interface	rip version { 1 | 2 [ broadcast | multicast ] }	Optional By default, the router receives RIP-1 and RIP-2 messages, but only sends RIP-1 messages. If the RIP version is 2, you can specify the message is broadcast or multicast.

 

 

2.3  RIP Route Control

In some complex network environments, you need to make the RIP configuration more precise.

Before configuring RIP routing information, finish the following tasks first:

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

l           Configure basic RIP functions

2.3.1  Configuring additional routing metric

To increase the value of routing metrics, you can add a value to the incoming or outgoing routing metric learned by RIP.

Follow these steps to configure additional routing metrics:

Operation	Command	Description
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Define an additional routing metric for incoming routes	rip metricin value	Optional 0 by default
Define an additional routing metric for outgoing routes	rip metricout value	Optional 1 by default

 

 

2.3.2  Configuring route summarization

The route summarization is that subnet routes in a natural network are summarized until the whole network is advertised as a single natural mask route. This function can reduce the size of the routing tables so that to reduce the network load.

RIP-1 does not support route summarization. So when RIP-2 is running, you need to disable the route summarization function if you want to advertise all subnet routes.

I. Enable RIP-2 automatic route summarization

Follow these steps to configure RIP route summarization:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Enable RIP-2 automatic route summarization	summary	Optional Enabled by default

 

II. Assign a summary IP address

Follow these steps to assign a summary IP address:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Disable RIP-2 automatic route summarization	undo summary	Optional Enabled by default
Return to system view	quit	––
Enter interface view	interface interface-type interface-number	––
Assign an IP address and network mask for the summarized routes to be advertised	rip summary-address ip-address network-{ mask | mask-length }	Optional

 

2.3.3  Disabling the receiving of host routes

In some cases, the router can get lots of routing information from the same network hosts, which are not helpful for routing but taking large of the network resources. After disabling the host route function, the router discards the host route information.

Follow these steps to configure host route:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Disabling the receiving of host routes	undo host-route	Optional Enabled by default

 

2.3.4  Configuring default route

Follow these steps to configure RIP default route:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Configure a RIP default route	default-route originate cost value	Required

 

2.3.5  Configuring route filtering

Route filtering is supported by the router. You can filter incoming and outgoing routes by setting the inbound and outbound filter policies in the access list and IP address prefixes list. You can also specify the incoming routes from particular neighbors.

Follow these steps to configure route filtering:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Define the filtering policy	filter-policy { acl-number | [ ip-prefix ip-prefix-name ][ gateway ip-prefix-name ] | gateway ip-prefix-name } import [ interface-type interface-number ]	Required
Define the filtering policy for the redistributed route	filter-policy { acl-number | ip-prefix ip-prefix-name } export [ protocol [ process-id ] | interface-type interface-number ]	Optional

 

2.3.6  Configuring protocol priority

Follow these steps to configure protocol priorities:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Set the protocol priority	preference [ route-policy route-policy-name ] value	Optional 100 by default

 

2.3.7  Redistributing route

Follow these steps to import exterior route:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Define a value for the default cost of the imported route	default-cost value	Optional If no value is set during importing, use this default value as the route cost.
Import a route	import-route protocol [ process-id ] [ cost cost-value | route-policy route-policy-name | tag tag-value ]*	Required

 

 

2.4  RIP Configuration Optimization

In special network environment, you need to configure some other RIP features to optimize the network performance.

Finish the following tasks before starting RIP optimization.

l           Configure network addresses on interfaces, make sure neighboring nodes are reachable

l           Configure RIP basic functions.

2.4.1  Configuring RIP timer

Follow these steps to configure the RIP timer:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Assign a value to each timer	timers { garbage-collect garbage-collect-value | suppress suppress-value | timeout timeout-value | update update-value }	Optional By default, 30s for update timer, 180s for timeout timer, 120s for Suppress timer, 240s for Garbage-collect timer

 

 

2.4.2  Configuring split horizon and poison reverse

Follow these steps to configure split horizon and poison reverse:

Operation	Command	Description
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Enable split horizon	rip split-horizon	Optional
Enable poison reverse	rip poison-reverse	Optional

 

 

2.4.3  Configuring RIP updating message validation

Some fields in RIP-1 message must be zero, which is called zero fields. The RIP-1 message is not processed if the value in the zero field is not zero.

The RIP router checks the source address when receiving messages. For messages received on the Ethernet interface, if the source address and the router’s interface address are not in the same network, the router discards the message.

Follow these steps to configure RIP updating message check

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Configure zero field check for RIP-1 message	checkzero	Optional Enabled by default
Configure source address validation	validate-source-address	Optional Enabled by default

 

 

2.4.4  Configuring RIP-2 message authentication

RIP-2 supports two authentication modes: plain text and MD5.

In plain text authentication, the authentication information is sent with the RIP message, which cannot provide high security guarantee.

Follow these steps to configure RIP-2 message authentication

Operation	Command	Description
Enter system view	system-view	––
Enter interface view	interface interface-type interface-number	––
Configure RIP-2 authentication mode	rip authentication-mode { simple password | md5 { rfc2082 key-string key-id | rfc2453 key-string } }	If the authentication mode is MD5, you must specify the message type defined in either RFC 2453 or RFC 2082.

 

2.4.5  Configuring RIP peer

Follow these steps to configure RIP peer:

Operation	Command	Description
Enter system view	system-view	––
Enter RIP view	rip [ process-id ]	––
Configure RIP peer	peer ip-address	Required No peer is defined by default
Disable source address validation	undo validate-source-address	Required Enabled by default

 

 

2.5  Displaying and Maintaining RIP

Operation	Command	Description
Display RIP current status and configuration information	display rip [ process-id |	Available in any view
Display RIP database	display rip process-id database
Display RIP interface information	display rip process-id interface [ interface-type interface-number ]
Display active and inactive RIP routes	display rip process-id route
Display RIP routing table	display rip process-id route [ statistics | ip-address mask | peer ip-address ]
Clear statistic data maintained by certain RIP processes	reset rip process-id statistics	Available in user view

 

2.6  RIP Configuration Example

2.6.1  Configuring RIP Version

I. Network requirements

As shown in Figure 2-4, enable RIP-2 on all interfaces on Switch A and Switch B.

II. Network diagram

Figure 2-4 Network diagram for RIP configuration

III. Configuration procedure

1)         Configure IP address for each interface (only the VLAN configuration procedures are given in the following examples)

# Configure SwitchA.

<SwitchA> system-view

[SwitchA] vlan 100

[SwitchA-vlan100]quit

[SwitchA]interface GigabitEthernet 1/0/1

[SwitchA-GigabitEthernet1/0/1]port access vlan 100

[SwitchA-GigabitEthernet1/0/1]quit

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ip-address 192.168.1.1 24

# Configure SwitchB.

<SwitchB> system-view

[SwitchB] vlan 100

[SwitchB-vlan100]quit

[SwitchB]interface GigabitEthernet 1/0/1

[SwitchB-GigabitEthernet1/0/1]port access vlan 100

[SwitchB-GigabitEthernet1/0/1]quit

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ip-address 192.168.1.2 24

2)         Configure basic RIP function

# Configure SwitchA.

<SwitchA> system-view

[SwitchA] rip

[SwitchA-rip-1] network 192.168.1.0

[SwitchA-rip-1] network 172.16.0.0

[SwitchA-rip-1] network 172.17.0.0

# Configure SwitchB.

<SwitchB> system-view

[SwitchB] rip

[SwitchB-rip-1] network 192.168.1.0

[SwitchB-rip-1] network 10.0.0.0

# Display routing table of SwitchA.

<SwitchA> display rip 1 route

 Route Flags: R - RIP, T - TRIP

              P - Permanent, A - Aging, S - Suppressed, G - Garbage-collect --------------------------------------------------------------------------

 Peer 192.168.1.2  on Vlan-interface100

      Destination/Mask        Nexthop     Cost    Tag   Flags   Sec

         10.0.0.0/8        192.168.1.2      1       0    RA      15

From the routing table, you can see RIP-1 use natural mask.

3)         Configure RIP version

# Configure RIP-2 of SwitchA.

<SwitchA> system-view

[SwitchA] rip

[SwitchA-rip-1] version 2

# Configure RIP-2 on SwitchB.

<SwitchB> system-view

[SwitchB] rip

[SwitchB-rip-1] version 2

[SwitchB-rip-1] undo summary

# Display routing table on SwitchA.

<SwitchA> display rip 1 route

 Route Flags: R - RIP, T - TRIP

              P - Permanent, A - Aging, S - Suppressed, G - Garbage-collect -------------------------------------------------------------------------

 Peer 192.168.1.2  on Vlan-interface100

      Destination/Mask        Nexthop     Cost    Tag   Flags   Sec

        10.2.1.0/24        192.168.1.2      1       0    RA      15

        10.1.1.0/24        192.168.1.2      1       0    RA      15

From the routing table, you can see RIP-2 use classless subnet mask.

 

 

2.7  Troubleshooting RIP Configuration

Symptom 1:

The device cannot get any RIP updating messages with all connections are alive.

Analysis:

After enabling RIP, make sure you use the network command to enable corresponding interfaces. If the interface behavior is configured, make sure you do not disable the interface or forbid receiving and forwarding RIP messages.

If RIP messages are multicast on the other end of the router, multicast should be used on the local router as well.

Solution:

l           Use the display current-configuration command to check RIP configuration.

l           Use the display rip command to check the interface is enabled.

Symptom 2:

With all connections alive, route shaking happens, which means that sometimes you cannot see some of the routes in the routing table.

Analysis:

In the RIP network, make sure all timers within the whole network are set to coordinate each other. For example, the timeout value should be greater than the update value.

Solution:

l           Use the display rip command to check the configuration of RIP timers

l           Use the timers command to adjust timers where appropriate.

 

Chapter 3  Routing Policy Configuration

 

 

3.1  Introduction to Routing Policy

3.1.1  Routing Policy

By modifying route attributes (including reachability), routing policy is adopted to change routing paths 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.

3.1.2  Filters

Routing protocols can use three filters: ACL, IP prefix list and route policy.

I. ACL

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

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. Moreover, you can specify the gateway option to specify that only routing information advertised by certain routers will be received.

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 ascending order. If an item is matched, the IP-prefix list filtering is passed, without the need of matching the next item.

III. 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.

3.1.3  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.

3.2  Defining IPv4 Prefix List

Before configuring this task, prepare the following data:

l           IP-prefix list name

l           Matching address range

Identified by name, each IPv4 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. For example, the following IPv4 prefix list named abcd:

ip ip-prefix abcd index 10 permit 1.0.0.0 8

ip ip-prefix abcd index 20 permit 2.0.0.0 8

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

To define an IPv4 prefix list, use the following commands:

Operation	Command	Description
Enter system view	system-view	—
Define an IPv4 prefix list	ip ip-prefix ip-prefix-name [ index index-number ] { permit | deny } ip-address mask-length [ greater-equal min-mask-length | less-equal max-mask-length ]	Required Not defined by default

 

 

3.3  Configuring a Routing Policy

Routing policy is used to match attributes in given routing information, and modify some attributes of the routing information after rules satisfied. 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.

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

3.3.1  Creating a Routing Policy

To create a routing policy, use the following commands:

Operation	Command	Description
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

 

 

3.3.2  Defining if-match Clauses for the Routing Policy

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

Operation	Command	Description
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
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
Define if-match clauses to match IPv4 routing information(source/destination address, next hop)	if-match ip { next-hop | route-source } { acl acl-number | ip-prefix ip-prefix-name }	Optional Not configured by default
Match the tag of RIP route	if-match tag value	Optional Not configured by default

 

 

3.3.3  Defining apply Clauses for the Routing Policy

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

Operation	Command	Description
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 the cost of routing information	apply cost [ + | - ] value	Optional Not set by default
Set the next hop for IPv4 routing information	apply ip-address next-hop ip-address	Optional Not set by default
Set routing protocol preference	apply preference preference	Optional Not set by default
Set the tag field of routing information	apply tag value	Optional

 

 

3.4  Displaying and Maintaining the Routing Policy

Operation	Command	Description
Display IPv4 prefix list statistics	display ip ip-prefix [ ip-prefix-name ]	Available in all views
Display routing policy information	display route-policy [ route-policy-name ]
Clear IPv4 prefix list statistics	reset ip ip-prefix [ ip-prefix-name ]	Available in user view

 

3.5  Routing Policy Configuration Example

3.5.1  Applying Routing Policy When Redistributing IPv4 Routes

I. Network Requirements

l           Switch A and Switch B communicate with each other, both using RIP.

l           Configure RIP process and static routes on Switch A.

l           Apply a routing policy when redistributing static routes, redistributing routes in 20.0.0.0/8 and 40.0.0.0/8 and filtering routes in 30.0.0.0/8

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

II. Network diagram

Figure 3-1 Network diagram for routing policy application to route redistribution

III. Configuration procedure

1)         Configure SwitchA.

# Configure IP addresses for interfaces.

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ip address 10.0.0.1 255.0.0.0

[SwitchA-Vlan-interface100] quit

[SwitchA] interface vlan-interface 200

[SwitchA-Vlan-interface200] ip address 12.0.0.1 255.0.0.0

[SwitchA-Vlan-interface200] quit

# Configure three static routes.

[SwitchA] ip route-static 20.0.0.1 255.0.0.0 12.0.0.2

[SwitchA] ip route-static 30.0.0.1 255.0.0.0 12.0.0.2

[SwitchA] ip route-static 40.0.0.1 255.0.0.0 12.0.0.2

# Enable RIP.

[SwitchA] rip

[SwitchA-rip-1]network 10.0.0.0

[SwitchA-rip-1] quit

# Configure an ACL.

[SwitchA] acl number 2000

[SwitchA-acl-basic-2000] rule deny source 30.0.0.0 0.255.255.255

[SwitchA-acl-basic-2000] rule permit source any

[SwitchA-acl-basic-2000] quit

# Configure a routing policy.

[SwitchA] route-policy ospf permit node 10

[SwitchA-route-policy] if-match acl 2000

[SwitchA-route-policy] quit

# Apply the routing policy for static route redistribution.

[SwitchA] rip

[SwitchA-rip-1] import-route static route-policy rip

2)         Configure Switch B.

# Configure IP addresses for interfaces.

<SwitchB> system-view

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ip address 10.0.0.2 255.0.0.0

[SwitchB-Vlan-interface100] quit

# Enable RIP.

[SwitchB] rip

[SwitchB-rip-1] network 10.0.0.0

# Display RIP routing table information to verify the configuration on Switch B.

<SwitchB>display rip 1 route

 Route Flags: R - RIP, T - TRIP

              P - Permanent, A - Aging, S - Suppressed, G - Garbage-collect --------------------------------------------------------------------------

 Peer 10.0.0.1  on Vlan-interface100

      Destination/Mask        Nexthop     Cost    Tag   Flags   Sec

         40.0.0.0/8           10.0.0.1      1       0    RA      29

         20.0.0.0/8           10.0.0.1      1       0    RA      29

3.6  Troubleshooting Routing Policy Configuration

3.6.1  IPv4 Routing Information Filtering Failed

I. Symptom

Filtering routing information failed, while routing protocol runs normally.

II. Analysis

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

III. Processing procedure

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

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