IPv6 Routing: Multiprotocol BGP Extensions for IPv6
Finding Feature Information
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Information About IPv6 Routing: Multiprotocol BGP Extensions for IPv6
Multiprotocol BGP Extensions for IPv6
Multiprotocol BGP is the supported Exterior Gateway Protocol (EGP) for IPv6. Multiprotocol BGP extensions for IPv6 supports many of the same features and functionality as IPv4 BGP. IPv6 enhancements to multiprotocol BGP include support for an IPv6 address family and Network Layer Reachability Information (NLRI) and next hop (the next device in the path to the destination) attributes that use IPv6 addresses.
How to Implement Multiprotocol BGP for IPv6
Configuring an IPv6 BGP Routing Process and BGP Router ID
Perform this task to configure an IPv6 BGP routing process and an optional BGP router ID for a BGP-speaking device.
BGP uses a router ID to identify BGP-speaking peers. The BGP router ID is 32-bit value that is often represented by an IPv4 address. By default, the router ID is set to the IPv4 address of a loopback interface on the device. If no loopback interface is configured on the device, then the software chooses the highest IPv4 address configured to a physical interface on the device to represent the BGP router ID.
When configuring BGP on a device that is enabled only for IPv6 (that is, the device does not have an IPv4 address), you must manually configure the BGP router ID for the device. The BGP router ID, which is represented as a 32-bit value using an IPv4 address syntax, must be unique to the BGP peers of the device.
Command or Action
Enables privileged EXEC mode.
Enter your password if prompted.
Device# configure terminal
Enters global configuration mode.
Device(config)# router bgp 65000
Configures a BGP routing process, and enters router configuration mode for the specified routing process.
Device(config-router)# no bgp default ipv4-unicast
Disables the IPv4 unicast address family for the BGP routing process specified in the previous step.
Routing information for the IPv4 unicast address family is advertised by default for each BGP routing session configured with the
neighborremote-as command unless you configure the
nobgpdefaultipv4-unicast command before configuring the
(Optional) Configures a fixed 32-bit router ID as the identifier of the local device running BGP.
Configuring a router ID using the
bgprouter-id command resets all active BGP peering sessions.
Configuring IPv6 Multiprotocol BGP Between Two Peers
By default, neighbors that are defined using the
neighborremote-as command in router configuration mode exchange only IPv4 unicast address prefixes. To exchange other address prefix types, such as IPv6 prefixes, neighbors must also be activated using the
neighboractivate command in address family configuration mode for the other prefix types, as shown for IPv6 prefixes.
Adds the IPv6 address of the neighbor in the specified autonomous system to the IPv6 multiprotocol BGP neighbor table of the local device.
address-familyipv6 [unicast |
Device(config-router)# address-family ipv6
Specifies the IPv6 address family and enters address family configuration mode.
unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified with the
multicast keyword specifies IPv6 multicast address prefixes.
Enables the neighbor to exchange prefixes for the IPv6 address family with the local device.
Advertising IPv4 Routes Between IPv6 BGP Peers
If an IPv6 network is connecting two separate IPv4 networks, IPv6 can be used to advertise the IPv4 routes. Configure the peering using the IPv6 addresses within the IPv4 address family. Set the next hop with a static route or with an inbound route map because the advertised next hop will usually be unreachable. Advertising IPv6 routes between two IPv4 peers is also possible using the same model.
Device(config-router-af)# neighbor 6peers route-map rmap out
Applies a route map to incoming or outgoing routes.
Changes to the route map will not take effect for existing peers until the peering is reset or a soft reset is performed. Using the
clearbgpipv6 command with the
in keywords will perform a soft reset.
Exits address family configuration mode, and returns the device to router configuration mode.
Exits router configuration mode, and returns the device to global configuration mode.
Device(config)# route-map rmap permit 10
Defines a route map and enters route-map configuration mode.
Example: Advertising Routes into IPv6 Multiprotocol BGP
The following example injects the IPv6 network 2001:DB8::/24 into the IPv6 unicast database of the local device. (BGP checks that a route for the network exists in the IPv6 unicast database of the local device before advertising the network.)
Example: Advertising IPv4 Routes Between IPv6 Peers
The following example advertises IPv4 routes between IPv6 peers when the IPv6 network is connecting two separate IPv4 networks. Peering is configured using IPv6 addresses in the IPv4 address family configuration mode. The inbound route map named rmap sets the next hop because the advertised next hop is likely to be unreachable.
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Feature Information for IPv6 Routing Multiprotocol BGP Extensions for IPv6
The following table
provides release information about the feature or features described in this
module. This table lists only the software release that introduced support for
a given feature in a given software release train. Unless noted otherwise,
subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform
support and Cisco software image support. To access Cisco Feature Navigator, go
An account on Cisco.com is not required.
Table 1 Feature Information for IPv6 Routing Multiprotocol BGP Extensions for IPv6
IPv6 Routing: Multiprotocol BGP Extensions for IPv6
Cisco IOS XE Release 2.1
Multiprotocol BGP extensions for IPv6 supports the same features and functionality as IPv4 BGP.