Deployment Guide

Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
50.0.0.2 200 0 0 0 0 0 00:00:00 0
Following is the output of show running-config bgp command for the above configuration.
DellEMC#show running-config bgp
!
router bgp 10
bgp router-id 1.1.1.1
network 10.10.21.0/24
bgp four-octet-as-support
neighbor 20.20.20.1 remote-as 65550
neighbor 20.20.20.1 no shutdown
!
address-family ipv4 vrf vrf1
neighbor 50.0.0.2 maximum-prefix 10000 warning-only
neighbor 50.0.0.2 remote-as 200
neighbor 50.0.0.2 no shutdown
exit-address-family
!
address-family ipv4 multicast vrf vrf1
neighbor 50.0.0.2 activate
exit-address-family
!
address-family ipv6 unicast vrf vrf1
neighbor 50.0.0.2 activate
exit-address-family
DellEMC#
Maintaining Existing AS Numbers During an AS Migration
The local-as feature smooths out the BGP network migration operation and allows you to maintain existing ASNs during a BGP
network migration.
When you complete your migration, be sure to reconfigure your routers with the new information and disable this feature.
● Allow external routes from this neighbor.
CONFIG-ROUTERBGP mode
neighbor {ip-address | ipv6-address | peer-group-name} local-as as number [no prepend]
○ peer-group-name: 16 characters.
○ AS-number: 0 to 65535 (2-Byte) or 1 to 4294967295 (4-Byte) or 0.1 to 65535.65535 (Dotted format).
○ No Prepend: specifies that local AS values are not prepended to announcements from the neighbor.
Format: IPv4 Address: A.B.C.D and IPv6 address: X:X:X:X::X.
You must Configure Peer Groups before assigning it to an AS. This feature is not supported on passive peer groups.
The first line in bold shows the actual AS number. The second two lines in bold show the local AS number (6500) maintained
during migration.
To disable this feature, use the no neighbor local-as command in CONFIGURATION ROUTER BGP mode.
R2(conf-router_bgp)#show conf
!
router bgp 65123
bgp router-id 192.168.10.2
network 10.10.21.0/24
network 10.10.32.0/24
network 100.10.92.0/24
network 192.168.10.0/24
bgp four-octet-as-support
neighbor 10.10.21.1 remote-as 65123
neighbor 10.10.21.1 filter-list Laura in
neighbor 10.10.21.1 no shutdown
neighbor 10.10.32.3 remote-as 65123
neighbor 10.10.32.3 no shutdown
neighbor 100.10.92.9 remote-as 65192
214
Border Gateway Protocol (BGP)