To support multiple network layer protocols, IETF extended BGP-4 by introducing IPv6 BGP that is defined in RFC 2858 (Multiprotocol Extensions for BGP-4).

To implement IPv6 support, IPv6 BGP puts IPv6 network layer information into the attributes of Network Layer Reachable Information (NLRI) and NEXT_HOP.

NLRI attribute of IPv6 BGP 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.

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

IPv6 BGP utilizes BGP multiprotocol extensions for application in IPv6 networks. The original messaging and routing mechanisms of BGP are not changed.

1.2 IPv6 BGP Configuration Task List

Complete the following tasks to configure IPv6 BGP:

Task		Remarks
Configuring IPv6 BGP Basic Functions	Configuring an IPv6 Peer	Required
	Advertising a Local IPv6 Route	Optional
	Configuring a Preferred Value for Routes 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
	Disabling Session Establishment to a Peer/Peer Group	Optional
	Logging Session State and Event Information of a Peer/Peer Group	Optional
Controlling Route Distribution and Reception	Configuring IPv6 BGP Route Redistribution	Optional
	Advertising a Default Route to a Peer/Peer Group	Optional
	Configuring Route Distribution Policy	Optional
	Configuring Route Reception Policy	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 Equal Cost 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

1.3 Configuring IPv6 BGP Basic Functions

1.3.1 Prerequisites

Before configuring this task, you need to:

l Specify IP addresses for interfaces.

l Enable IPv6.

& Note:

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

1.3.2 Configuring an IPv6 Peer

Follow these steps to configure an IPv6 peer:

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

1.3.3 Advertising a Local IPv6 Route

Follow these steps to 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	Required
Enter IPv6 address family view	ipv6-family	—
Add a local route into IPv6 BGP routing table	network ipv6-address prefix-length [ short-cut \| route-policy route-policy-name ]	Required Not added by default

1.3.4 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	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.

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

Follow these steps to specify a local update source interface connected to a peer:

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 an IPv6 BGP connection as loopback interface. By doing so, a connection failure upon redundancy availability will not affect IPv6 BGP connection.

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

Follow these steps to configure an EBGP connection to a peer not directly connected:

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, 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 with loopback interfaces.

1.3.7 Configuring Description for a Peer/Peer Group

Follow these steps to configure description for a peer/peer group:

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 a description must have been created.

1.3.8 Disabling Session Establishment to a 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	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

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

Follow these steps to log the session and event information of a peer/peer group:

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 for information about the log-peer-change command.

1.4 Controlling Route Distribution and Reception

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

1.4.1 Prerequisites

Before configuring this task, you have:

l Enabled the IPv6 function

l Configured the IPv6 BGP basic functions

1.4.2 Configuring IPv6 BGP Route Redistribution

Follow these steps to configure IPv6 BGP route redistribution and 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	—
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

& Note:

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

1.4.3 Advertising a Default Route to a Peer/Peer Group

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

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.

1.4.4 Configuring Route Distribution Policy

Follow these steps to configure policies for route distribution:

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 outbound route filtering	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 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 After configuring the filtering of routes to a peer group, you can also configure the filtering of routes to a member of the peer group, and the last configuration takes effect.

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

1.4.5 Configuring Route Reception Policy

Follow these steps to configure route reception policy:

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 a peer/peer group	peer { ipv6-group-name \| ipv6-address } route-policy route-policy-name import	Required Not applied by default
Reference 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
Reference 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
Reference 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, the number of prefixes is unlimited. If the received IPv6 prefixes exceed the upper limit, the neighbor is still maintained but the exceeding routes will be discarded.

& Note:

l Only routes passing the specified policy can be added into the local IPv6 BGP routing table.

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

1.4.6 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	Required
Enter IPv6 address family view	ipv6-family	—
Enable route synchronization between IPv6 BGP and IGP	synchronization	Required Not enabled by default

1.4.7 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	Required
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

1.5 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

1.5.1 Prerequisites

Before configuring this task, you have:

l Enabled IPv6 function

l Configured IPv6 BGP basic functions

1.5.2 Configuring IPv6 BGP Preference and Default LOCAL_PREF and NEXT_HOP Attributes

Follow these steps to configure IPv6 BGP preference and default LOCAL_PREF and NEXT_HOP attributes:

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 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 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	Required 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 specifies itself as the next hop of outbound routes to a 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 EBGP peers reside in a common broadcast subnet, the router does not specify itself as the next hop for routes to the EBGP peer by default, unless the peer next-hop-local command is configured.

1.5.3 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	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

1.5.4 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	Required
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 a peer/peer group	peer { ipv6-group-name \| ipv6-address } fake-as as-nmber	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

1.6 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 holdtime values, taking the shorter one as the common holdtime. If the holdtime is 0, neither keepalive massage is sent, nor is holdtime 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 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 IPv6 BGP connections.

1.6.1 Prerequisites

Before configuring IPv6 BGP timers, you have:

l Enabled IPv6 function

l Configured IPv6 BGP basic functions

1.6.2 Configuring IPv6 BGP Timers

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	Required
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 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.

1.6.3 Configuring IPv6 BGP Soft Reset

I. 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	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

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	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	Required
Soft-reset BGP connections manually	refresh bgp ipv6 { all \| ipv6-address \| group ipv6-group-name \| external \| internal } { export \| import }	Required

1.6.4 Configuring the Maximum Number of Equal Cost Routes

Follow these steps to configure the maximum number of equal cost routes for load balancing:

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 equal cost routes for load balancing	balance number	Required By default, no load balancing is enabled.

1.7 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.

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 BGP, so it is not mentioned here. The following describes:

l Configuring an IPv6 BGP peer group

l Configuring the IPv6 BGP community

l Configuring an IPv6 BGP route reflector

1.7.1 Prerequisites

Before configuring an IPv6 BGP peer group, you have:

l Made peer nodes accessible at the network layer

l Enabled BGP and configured router ID.

1.7.2 Configuring IPv6 BGP Peer Group

I. Create an IBGP peer group

Follow these steps to create an IBGP group:

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

& Note:

After you add an IPv6 IBGP peer to the peer group, the system will automatically create the peer in BGP view and enable the IPv6 peer in IPv6 address family view.

II. Create 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	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 After you add an IPv6 EBGP peer to the peer group, the system will automatically create the EBGP peer in BGP view and enable the EBGP peer in IPv6 address family view.

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.

III. Create 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	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:

l After you add an IPv6 EBGP peer to the peer group, the system will automatically create the EBGP peer in IPv6 address family view.

l 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.

1.7.3 Configuring IPv6 BGP Community

I. Advertise community attribute to a peer/peer group

Follow these steps to advertise community attribute to a peer/peer group:

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
Advertise extended community attribute to a peer/peer group	peer { ipv6-group-name \| ipv6-address } advertise-ext-community	Required Not advertised by default

II. 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	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 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.

1.7.4 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	Required
Enter IPv6 address family view	ipv6-family	—
Configure the router as a route 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 route reflector	reflector cluster-id cluster-id	Optional By default, a route reflector uses its router ID as the cluster ID

& Note:

l In general, since the route reflector forwards routing information between clients, it is not required to make clients 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.

1.8 Displaying and Maintaining IPv6 BGP Configuration

1.8.1 Displaying IPv6 BGP Configuration

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 [ ipv6-address { log-info \| verbose } \| ipv6-group-name log-info \| verbose ]
Display IPv6 BGP routing table information	display bgp ipv6 routing-table [ ipv6-address prefix-length ]
Display IPv6 BGP routing information matching a AS path ACL	display bgp ipv6 routing-table as-path-acl as-path-acl-number
Display IPv6 BGP community routing information	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 labeled IPv6 BGP routing information	display bgp ipv6 routing-table label
Display IPv6 BGP routing information to or from an IPv6 BGP peer	display bgp ipv6 routing-table peer ipv6-address { advertised-routes \| received-routes } [ network-address prefix-length \| statistic ]
Display IPv6 BGP routing information matching the regular expression	display bgp ipv6 routing-table regular-expression as-regular-expression
Display IPv6 BGP routing statistics	display bgp ipv6 routing-table statistic

1.8.2 Resetting IPv6 BGP Connections

To do…	Use the command…	Remarks
Reset all IPv6 BGP connections	reset bgp ipv6 all	Available in user view
Reset IPv6 BGP connections to an AS	reset bgp ipv6 as-number
Reset the IPv6 BGP connection to a peer	reset bgp ipv6 ipv6-address [ flap-info ]
Reset all IPv6 EBGP connections	reset bgp ipv6 external
Reset the IPv6 BGP connections to an IPv6 peer group	reset bgp ipv6 group ipv6-group-name
Reset all IPv6 IBGP connections	reset bgp ipv6 internal

1.8.3 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

1.9 IPv6 BGP Configuration Examples

& Note:

Some examples for IPv6 BGP configuration are similar to those of BGP4, so refer to BGP Configuration for related information.

1.9.1 IPv6 BGP Basic Configuration

I. 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 IBGP fully meshed.

II. Network diagram

Figure 1-1 IPv6 BGP 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.

1.9.2 IPv6 BGP Route Reflector Configuration

I. 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.

II. Network diagram

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

III. 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] ipv6-family

[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.

1.10 Troubleshooting IPv6 BGP Configuration

1.10.1 No IPv6 BGP Peer Relationship Established

I. Symptom

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

II. Analysis

To become IPv6 BGP 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 ipv6 status command to check the TCP connection.

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

H3C S9500 Operation Manual-Release2132[V2.03]-03 IP Routing Volume

1.1 IPv6 BGP Overview

1.2 IPv6 BGP Configuration Task List

1.3 Configuring IPv6 BGP Basic Functions

1.3.2 Configuring an IPv6 Peer

1.3.3 Advertising a Local IPv6 Route

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

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

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

1.3.7 Configuring Description for a Peer/Peer Group

1.3.8 Disabling Session Establishment to a Peer/Peer Group

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

1.4 Controlling Route Distribution and Reception

1.4.2 Configuring IPv6 BGP Route Redistribution

1.4.3 Advertising a Default Route to a Peer/Peer Group

1.4.4 Configuring Route Distribution Policy

1.4.5 Configuring Route Reception Policy

1.4.6 Configuring IPv6 BGP and IGP Route Synchronization

1.4.7 Configuring Route Dampening

1.5 Configuring IPv6 BGP Route Attributes

1.5.2 Configuring IPv6 BGP Preference and Default LOCAL_PREF and NEXT_HOP Attributes

1.5.3 Configuring the MED Attribute

1.5.4 Configuring the AS_PATH Attribute

1.6 Tuning and Optimizing IPv6 BGP Networks

1.6.2 Configuring IPv6 BGP Timers

1.6.3 Configuring IPv6 BGP Soft Reset

I. Enable route refresh

II. Perform manual soft-reset

1.6.4 Configuring the Maximum Number of Equal Cost Routes

1.7 Configuring a Large Scale IPv6 BGP Network

1.7.2 Configuring IPv6 BGP Peer Group

I. Create an IBGP peer group

II. Create a pure EBGP peer group

III. Create a mixed EBGP peer group

1.7.3 Configuring IPv6 BGP Community

I. Advertise community attribute to a peer/peer group

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

1.7.4 Configuring an IPv6 BGP Route Reflector

1.8 Displaying and Maintaining IPv6 BGP Configuration

1.8.1 Displaying IPv6 BGP Configuration

1.9 IPv6 BGP 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. Processing steps

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