Users Guide

Table Of Contents
4. Add a remote AS in ROUTER-NEIGHBOR mode, from 1 to 65535 for 2-byte or 1 to 4294967295 for 4-byte.
remote-as as-number
5. Enable the BGP neighbor in ROUTER-NEIGHBOR mode.
no shutdown
6. (Optional) Add a description text for the neighbor in ROUTER-NEIGHBOR mode.
description text
To reset the configuration when you change the configuration of a BGP neighbor, use the clear ip bgp * command. To
view the BGP status, use the show ip bgp summary command.
Configure BGP
OS10# configure terminal
OS10(config)# router bgp 100
OS10(config-router-bgp-100)# vrf blue
OS10(config-router-vrf)# neighbor 5.1.1.1
OS10(config-router-neighbor)# remote-as 1
OS10(config-router-neighbor)# description n1_abcd
OS10(config-router-neighbor)# exit
OS10(config-router-vrf)# template t1
OS10(config-router-template)# description peer_template_1_abcd
BGP over unnumbered interfaces
As BGP relies on TCP for connection between peers, the interface that connects to the peer requires a unique IP address.
Assigning an IP address to every interface may exhaust the available pool of IP addresses and is error prone. Unnumbered
interfaces are the interfaces without unique IP addresses. BGP unnumbered interfaces use the extended next hop encoding
(ENHE) feature, which is defined by RFC 5549. BGP unnumbered interfaces can advertise IPv4 routes with an IPv6 next hop.
As IPv6 link-local addresses are automatically configured on connected interfaces, BGP uses these link-local addresses to form
neighborship. Unnumbered interfaces use IPv6 router advertisements to identify the address of the peer.
Restrictions
You cannot configure VRRP for IPv6 on an unnumbered interface. This configuration causes BGP session failure.
You cannot use the default VLAN as the unnumbered VLAN.
Route reflectors are not supported with unnumbered peers.
Confederations are not supported with unnumbered peers.
Dampening is not supported with unnumbered peers.
Configure an unnumbered neighbor
To configure an unnumbered neighbor:
1. Create an interface, if required, in CONFIGURATION mode.
interface interface-type
interface interface-type (Optional) Enter one of the following interface types:
ethernet node/slot/port[:subport] Display Ethernet interface information.
port-channel id-number Display port channel interface IDs, from 1 to 128.
vlan vlan-id Display the VLAN interface number, from 1 to 4093.
2. Enable RAs on the interface in INTERFACE mode.
ipv6 nd send-ra
3. Configure minimum and maximum RA intervals in INTERFACE mode.
ipv6 nd min-ra-interval 3
ipv6 nd max-ra-interval 4
Layer 3
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