To support multiple network layer protocols, IETF extended BGP-4 by introducing Multiprotocol BGP (MP-BGP), which is defined in RFC 2858 (multiprotocol extensions for BGP-4).

MP-BGP for IPv6 is referred to as IPv6 BGP for short.

IPv6 BGP puts IPv6 network layer information into the attributes of network layer reachable information (NLRI) and NEXT_HOP.

The NLRI attribute of IPv6 BGP involves:

l MP_REACH_NLRI: Multiprotocol Reachable NLRI, for advertising reachable route and next hop information.

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

The NEXT_HOP attribute of IPv6 BGP is identified by an IPv6 unicast address or IPv6 local link address.

IPv6 BGP has the same messaging and routing mechanisms as BGP.

Configuration Task List

Complete the following tasks to configure IPv6 BGP:

Task		Remarks
Configuring IPv6 BGP Basic Functions	Specifying an IPv6 BGP Peer	Required
	Injecting a Local IPv6 Route	Optional
	Configuring a Preferred Value for Routes from a Peer/Peer Group	Optional
	Specifying the Source Interface for Establishing TCP Connections	Optional
	Allowing the establishment of a Non-Direct eBGP connection	Optional
	Configuring a Description for an IPv6 Peer/Peer Group	Optional
	Disabling Session Establishment to an IPv6 Peer/Peer Group	Optional
	Logging IPv6 Peer/Peer Group State Changes	Optional
Controlling Route Distribution and Reception	Configuring IPv6 BGP Route Redistribution	Optional
	Advertising a Default Route to an IPv6 Peer/Peer Group	Optional
	Configuring Outbound Route Filtering	Optional
	Configuring Inbound Route Filtering	Optional
	Configuring IPv6 BGP and IGP Route Synchronization	Optional
	Configuring Route Dampening	Optional
Configuring IPv6 BGP Route Attributes	Configuring IPv6 BGP Preference and Default LOCAL_PREF and NEXT_HOP Attributes	Optional
	Configuring the MED Attribute	Optional
	Configuring the AS_PATH Attribute	Optional
Tuning and Optimizing IPv6 BGP Networks	Configuring IPv6 BGP Timers	Optional
	Configuring IPv6 BGP Soft Reset	Optional
	Configuring the Maximum Number of Load-Balanced Routes	Optional
Configuring a Large Scale IPv6 BGP Network	Configuring IPv6 BGP Peer Group	Optional
	Configuring IPv6 BGP Community	Optional
	Configuring an IPv6 BGP Route Reflector	Optional

Configuring IPv6 BGP Basic Functions

Prerequisites

Before configuring this task, you need to:

l Specify IP addresses for interfaces.

l Enable IPv6.

You need create a peer group before configuring basic functions for it. For related information, refer to Configuring IPv6 BGP Peer Group.

Specifying an IPv6 BGP Peer

Follow these steps to configure an IPv6 BGP peer:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Specify a router ID	router-id router-id	Optional Required if no IP addresses are configured for any 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.

Injecting a Local IPv6 Route

Follow these steps to configure advertise a local route into the routing table:

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

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

Follow these steps to configure a preferred value for routes received from a peer/peer group:

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

If you both reference a routing policy and use the command peer { ipv6-group-name | ipv6-address } preferred-value value to set a preferred value for routes from a peer/peer group, the routing policy sets a non-zero preferred value for routes matching it. Other routes not matching the routing policy uses the value set with the command. If the preferred value in the routing policy is zero, the routes matching it will also use the value set with the command. For information about using a routing policy to set a preferred value, refer to the command peer { group-name | ipv4-address | ipv6-address } route-policy route-policy-name { import | export } in this document, and the command apply preferred-value preferred-value in Routing Policy Commands of the IP Routing Volume.

Specifying the Source Interface for Establishing TCP Connections

Follow these steps to specify the source interface for establishing TCP connections to a BGP peer or peer group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Specify the source interface for establishing TCP connections to an IPv6 BGP peer or peer group	peer { ipv6-group-name \| ipv6-address } connect-interface interface-type interface-number	Required By default, IPv6 BGP uses the outbound interface of the best route to the IPv6 BGP peer or peer group as the source interface for establishing a TCP connection.

l To improve stability and reliability, you can specify a loopback interface as the source interface for establishing TCP connections to a BGP peer. By doing so, a connection failure upon redundancy availability will not affect TCP connection establishment.

l To establish multiple BGP connections to a BGP router, you need to specify on the local router the respective source interfaces for establishing TCP connections to the peers on the peering BGP router; otherwise, the local BGP router may fail to establish TCP connections to the peers when using the outbound interfaces of the best routes as the source interfaces.

Allowing the establishment of a Non-Direct eBGP connection

Follow these steps to allow the establishment of eBGP connection to a non-directly connected peer/peer group:

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

In general, direct links should be available between eBGP peers. If not, 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 connections with loopback interfaces.

Configuring a Description for an IPv6 Peer/Peer Group

Follow these steps to configure description for an IPv6 peer/peer group:

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

The peer group to be configured with a description must have been created.

Disabling Session Establishment to an IPv6 Peer/Peer Group

Follow these steps to disable session establishment to a peer/peer group:

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

Logging IPv6 Peer/Peer Group State Changes

Follow these steps to configure to log on the session and event information of an IPv6 peer/peer group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enable logging of peer changes globally	log-peer-change	Optional Enabled by default.
Enter IPv6 address family view	ipv6-family	—
Enable the state change logging for an IPv6 peer or peer group	peer { ipv6-group-name \| ipv6-address } log-change	Optional Enabled by default.

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

Controlling Route Distribution and Reception

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

Prerequisites

Before configuring this task, you need to:

l Enable IPv6

l Configure the IPv6 BGP basic functions

Configuring IPv6 BGP Route Redistribution

Follow these steps to configure IPv6 BGP route redistribution:

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

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

Advertising a Default Route to an IPv6 Peer/Peer Group

Follow these steps to advertise a default route to an IPv6 peer/peer group:

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

With the peer default-route-advertise command executed, the local router advertises a default route with itself as the next hop to the specified IPv6 peer/peer group, regardless of whether the default route is available in the routing table.

Configuring Outbound Route Filtering

Follow these steps to configure outbound route filtering:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Configure the filtering of outgoing routes	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } export [ protocol process-id ]	Required Not configured by default.
Apply a routing policy to routes advertised to an IPv6 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 an IPv6 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 an IPv6 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 an IPv6 peer/peer group	peer { ipv6-group-name \| ipv6-address } ipv6-prefix ipv6-prefix-name export	Required Not specified by default.

IPv6 BGP advertises routes passing the specified policy to peers. Using the protocol argument can filter only the routes redistributed from the specified protocol. If no protocol is specified, IPv6 BGP filters all routes to be advertised, including redistributed routes and routes imported with the network command.

Configuring Inbound Route Filtering

Follow these steps to configure inbound route filtering:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Configure inbound route filtering	filter-policy { acl6-number \| ipv6-prefix ipv6-prefix-name } import	Required Not configured by default.
Apply a routing policy to routes from an IPv6 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 an IPv6 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 an IPv6 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 an IPv6 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 prefixes allowed to receive from an IPv6 peer/peer group	peer { ipv6-group-name \| ipv6-address } route-limit limit [ percentage ]	Optional Unlimited by default.

l Only routes passing the configured filtering can be added into the local IPv6 BGP routing table.

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

Configuring IPv6 BGP and IGP Route Synchronization

With this feature enabled and when a non-BGP router is responsible for forwarding packets in an AS, IPv6 BGP 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 BGP 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.

Follow these steps to configure IPv6 BGP and IGP route synchronization:

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

Currently, the system does not support synchronization. Therefore, the configuration of this command does not actually take effect.

Configuring Route Dampening

Follow these steps to configure BGP route dampening:

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

Configuring IPv6 BGP Route Attributes

This section describes how to use IPv6 BGP route attributes to modify BGP routing policy. These attributes are:

l IPv6 BGP protocol preference

l Default LOCAL_PREF attribute

l MED attribute

l NEXT_HOP attribute

l AS_PATH attribute

Prerequisites

Before configuring this task, you have:

l Enabled IPv6 function

l Configured IPv6 BGP basic functions

Configuring IPv6 BGP Preference and Default LOCAL_PREF and NEXT_HOP Attributes

Follow these steps to perform this configuration:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Configure preference values for IPv6 BGP 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 local preference	default local-preference value	Optional The value defaults to 100.
Advertise routes to an IPv6 peer/peer group with the local router as the next hop	peer { ipv6-group-name \| ipv6-address } next-hop-local	Required By default, IPv6 BGP specifies the local router as the next hop for routes sent to an IPv6 eBGP peer/peer group, but not for routes sent to an IPv6 iBGP peer/peer group.

l To make sure an iBGP peer can find the correct next hop, you can configure routes advertised to the IPv6 iBGP peer/peer group to use the local router as the next hop. If BGP load balancing is configured, the local router specifies itself as the next hop of routes sent to an IPv6 iBGP peer/peer group regardless of whether the peer next-hop-local command is configured.

l In a “third party next hop" network, that is, the two IPv6 eBGP peers reside in a common broadcast subnet, the router does not specify itself as the next hop for routes sent to the IPv6 eBGP peer/peer group by default, unless the peer next-hop-local command is configured.

Configuring the MED Attribute

Follow these steps to configure the MED attribute:

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

Configuring the AS_PATH Attribute

Follow these steps to configure the AS_PATH attribute:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Allow the local AS number to appear in AS_PATH of routes from a peer/peer group and specify the repeat times	peer { ipv6-group-name \| ipv6-address } allow-as-loop [ number ]	Optional Not allowed by default
Specify a fake AS number for an IPv6 peer/peer group	peer { ipv6-group-name \| ipv6-address } fake-as as-number	Optional Not specified by default.
Disable IPv6 MBGP from considering the AS_PATH during best route selection	bestroute as-path-neglect	Optional Enabled 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, IPv6 BGP updates carry private AS number.
Substitute the local AS number for the AS number of an IPv6 peer/peer group identified in the AS_PATH attribute	peer { ipv6-group-name \| ipv6-address } substitute-as	Optional Not substituted by default

Tuning and Optimizing IPv6 BGP Networks

This section describes configurations of IPv6 BGP timers, IPv6 BGP connection soft reset and the maximum number of load balanced routes.

l IPv6 BGP timers

After establishing an IPv6 BGP 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 an IPv6 BGP connection, the two parties compare their holdtimes, taking the shorter one as the common holdtime. If the holdtime is 0, neither keepalive massage is sent, nor holdtime is checked.

l IPv6 BGP connection soft reset

After modifying a route selection policy, you have to reset IPv6 BGP connections to make the new one take effect, causing a short time disconnection. The current IPv6 BGP implementation supports the route-refresh feature that enables dynamic IPv6 BGP routing table refresh without needing to disconnect IPv6 BGP links.

With this feature enabled on all IPv6 BGP 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 peer not supporting route-refresh exists in the network, you need to configure the peer keep-all-routes command on the router to save all routes from the peer. When the routing policy is changed, the system will update the IPv6 BGP routing table and apply the new policy.

Prerequisites

Before configuring IPv6 BGP timers, you need to:

l Enable IPv6

l Configure IPv6 BGP basic functions

Configuring IPv6 BGP Timers

Follow these steps to configure IPv6 BGP timers:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter BGP view		bgp as-number	—
Enter IPv6 address family view		ipv6-family	—
Configure IPv6 BGP 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 IPv6 BGP timers	Configure keepalive interval and holdtime for an IPv6 peer/peer group	peer { ipv6-group-name \| ipv6-address } timer keepalive keepalive hold holdtime
Configure the interval for sending the same update to an IPv6 peer/peer group		peer { ipv6-group-name \| ipv6-address } route-update-interval interval	Optional The interval for sending the same update to an iBGP peer or an eBGP peer defaults to 15 seconds or 30 seconds

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.

Configuring IPv6 BGP Soft Reset

Enable route refresh

Follow these steps to enable route refresh:

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

Perform manual soft-reset

Follow these steps to perform manual soft reset:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Save all routes from an IPv6 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	Required
Soft-reset BGP connections manually	refresh bgp ipv6 { all \| ipv6-address \| group ipv6-group-name \| external \| internal } { export \| import }	Required

If the peer keep-all-routes command is used, all routes from the peer/peer group will be saved regardless of whether the filtering policy is available. These routes will be used to generate IPv6 BGP routes after soft-reset is performed.

Configuring the Maximum Number of Load-Balanced Routes

Follow these steps to configure the maximum number of load balanced routes:

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

Configuring a Large Scale IPv6 BGP Network

In a large-scale IPv6 BGP network, configuration and maintenance become no convenient due to too many peers. In this case, configuring peer groups makes management easier and improves route distribution efficiency. Peer group includes iBGP peer group, where peers belong to the same AS, and eBGP peer group, where peers belong to different ASs. If peers in an eBGP group belong to the same external AS, the eBGP peer group is a pure eBGP peer group, and if not, a mixed eBGP peer group.

In a peer group, all members enjoy a common policy. Using the community attribute can make a set of IPv6 BGP routers in multiple ASs enjoy the same policy, because sending of community between IPv6 BGP peers is not limited by AS.

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 route reflectors or confederation can solve it. In a large-scale AS, both of them can be used.

Confederation configuration of IPv6 BGP is identical to that of BGP4, so it is not mentioned here. The following describes:

l Configuring IPv6 BGP peer groups

l Configuring IPv6 BGP community

l Configuring IPv6 BGP route reflectors

Prerequisites

Before configuring IPv6 BGP peer groups, you need to:

l Make peer nodes accessible to each other at the network layer

l Enable BGP and configure a router ID.

Configuring IPv6 BGP Peer Group

Configuring an iBGP peer group

Follow these steps to configure an iBGP group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
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

Creating a pure eBGP peer group

Follow these steps to configure a pure eBGP group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
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

l To create a pure eBGP peer group, you need to specify an 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.

Creating a mixed eBGP peer group

Follow these steps to create a mixed eBGP peer group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
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

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 AS number for the eBGP peer group.

Configuring IPv6 BGP Community

Advertise community attribute to an IPv6 peer/peer group

Follow these steps to advertise community attribute to an IPv6 peer/peer group:

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

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

Follow these steps to apply a routing policy to routes advertised to a peer/peer group:

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

l When configuring IPv6 BGP 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 Routing Policy Configuration in the IP Routing Volume.

Configuring an IPv6 BGP Route Reflector

Follow these steps to configure an IPv6 BGP route reflector:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter BGP view	bgp as-number	—
Enter IPv6 address family view	ipv6-family	—
Configure the router as a route reflector and specify an IPv6 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 route reflector	reflector cluster-id cluster-id	Optional By default, a route reflector uses its router ID as the cluster ID

l In general, since the route reflector forwards routing information between clients, it is not required to make clients of a route reflector fully meshed. If clients are fully meshed, it is recommended to disable route reflection between clients to reduce routing costs.

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

Displaying and Maintaining IPv6 BGP

Displaying BGP

To do…	Use the command…	Remarks
Display IPv6 BGP peer group information	display bgp ipv6 group [ ipv6-group-name ]	Available in any view
Display IPv6 BGP advertised routing information	display bgp ipv6 network
Display IPv6 BGP AS path information	display bgp ipv6 paths [ as-regular-expression ]
Display IPv6 BGP peer/peer group information	display bgp ipv6 peer [ group-name log-info \| ipv4-address verbose \| ipv6-address { log-info \| verbose } \| verbose ]
Display IPv6 BGP routing table information	display bgp ipv6 routing-table [ ipv6-address prefix-length ]
Display IPv6 BGP routing information matching an AS path ACL	display bgp ipv6 routing-table as-path-acl as-path-acl-number
Display IPv6 BGP routing information with the specified community attribute	display bgp ipv6 routing-table community [ aa:nn<1-13> ] [ no-advertise \| no-export \| no-export-subconfed ]* [ whole-match ]
Display IPv6 BGP routing information matching an IPv6 BGP community list	display bgp ipv6 routing-table community-list { basic-community-list-number [ whole-match ] \| adv-community-list-number }&<1-16>
Display dampened IPv6 BGP routing information	display bgp ipv6 routing-table dampened
Display IPv6 BGP dampening parameter information	display bgp ipv6 routing-table dampening parameter
Display IPv6 BGP routing information originated from different ASs	display bgp ipv6 routing-table different-origin-as
Display IPv6 BGP 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 BGP routing information to or from an IPv4 or IPv6 peer	display bgp ipv6 routing-table peer { ipv4-address \| ipv6-address } { advertised-routes \| received-routes } [ network-address prefix-length \| statistic ]
Display IPv6 BGP routing information matching a regular expression	display bgp ipv6 routing-table regular-expression as-regular-expression
Display IPv6 BGP routing statistics	display bgp ipv6 routing-table statistic

Resetting IPv6 BGP Connections

To do…	Use the command…	Remarks
Perform soft reset on IPv6 BGP connections	refresh bgp ipv6 { ipv4-address \| ipv6-address \| all \| external \| group ipv6-group-name \| internal } { export \| import }	Available in user view
Reset IPv6 BGP connections	reset bgp ipv6 { as-number \| ipv4-address \| ipv6-address [ flap-info ] \| all \| group group-name \| external \| internal }	Available in user view

Clearing IPv6 BGP Information

To do…	Use the command…	Remarks
Clear dampened IPv6 BGP routing information and release suppressed routes	reset bgp ipv6 dampening [ ipv6-address prefix-length ]	Available in user view
Clear IPv6 BGP 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

IPv6 BGP Configuration Examples

Some examples for IPv6 BGP configuration are similar to those of BGP4, so refer to BGP Configuration in the IP Routing Volume for related information.

IPv6 BGP Basic Configuration

Network requirements

In the following figure are all IPv6 BGP switches. Between Switch A and Switch B is an eBGP connection. Switch B, Switch C and Switch D are fully meshed through iBGP connections.

Network diagram

Figure 1-1 IPv6 BGP basic configuration network diagram

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 has established an eBGP connection; Switch B, C and D have established iBGP connections with each other.

IPv6 BGP Route Reflector Configuration

Network requirements

Switch B receives an eBGP update and sends it to Switch C, which is configured as a route 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.

Network diagram

Figure 1-2 Network diagram for IPv6 BGP route reflector configuration

Configuration procedure

1) Configure IPv6 addresses for VLAN interfaces (omitted)

2) Configure IPv6 BGP 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

#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

[SwitchB-bgp-af-ipv6] peer 101::1 next-hop-local

# 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 route reflector

# Configure Switch C as a route 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.

Troubleshooting IPv6 BGP Configuration

No IPv6 BGP Peer Relationship Established

Symptom

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

Analysis

To become IPv6 BGP peers, any two routers need to establish a TCP session using port 179 and exchange open messages successfully.

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 ipv6 status command to check the TCP connection.

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

03-IP Routing Volume

IPv6 BGP Overview

Configuration Task List

Configuring IPv6 BGP Basic Functions

Specifying an IPv6 BGP Peer

Injecting a Local IPv6 Route

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

Specifying the Source Interface for Establishing TCP Connections

Allowing the establishment of a Non-Direct eBGP connection

Configuring a Description for an IPv6 Peer/Peer Group

Disabling Session Establishment to an IPv6 Peer/Peer Group

Logging IPv6 Peer/Peer Group State Changes

Controlling Route Distribution and Reception

Configuring IPv6 BGP Route Redistribution

Advertising a Default Route to an IPv6 Peer/Peer Group

Configuring Outbound Route Filtering

Configuring Inbound Route Filtering

Configuring IPv6 BGP and IGP Route Synchronization

Configuring Route Dampening

Configuring IPv6 BGP Route Attributes

Configuring IPv6 BGP Preference and Default LOCAL_PREF and NEXT_HOP Attributes

Configuring the MED Attribute

Configuring the AS_PATH Attribute

Tuning and Optimizing IPv6 BGP Networks

Configuring IPv6 BGP Timers

Configuring IPv6 BGP Soft Reset

Enable route refresh

Perform manual soft-reset

Configuring the Maximum Number of Load-Balanced Routes

Configuring a Large Scale IPv6 BGP Network

Configuring IPv6 BGP Peer Group

Configuring an iBGP peer group

Creating a pure eBGP peer group

Creating a mixed eBGP peer group

Configuring IPv6 BGP Community

Advertise community attribute to an IPv6 peer/peer group

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

Configuring an IPv6 BGP Route Reflector

Displaying and Maintaining IPv6 BGP

IPv6 BGP Configuration Examples

Network requirements

Network diagram

Configuration procedure

Network requirements

Network diagram

Configuration procedure

Symptom

Analysis

Processing steps

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