Administrator Guide

Dell(conf-router_bgp)#do show ip bgp
BGP table version is 24901, local router ID is 172.30.1.57
<output truncated>
ASDOT+
Dell(conf-router_bgp)#
bgp asnotation asdot+
Dell(conf-router_bgp)#show conf
!
router bgp 100
bgp asnotation asdot
bgp four-octet-as-support
neighbor 172.30.1.250 local-as 65057
<output truncated>
Dell(conf-router_bgp)#do show ip bgp
BGP table version is 24901, local router ID is 172.30.1.57
<output truncated>
AS-PLAIN
Dell(conf-router_bgp)#
bgp asnotation asplain+
Dell(conf-router_bgp)#sho conf
!
router bgp 100
bgp four-octet-asdot+
bgp four-octet-as-support
neighbor 172.30.1.250
local-as 65057
<output truncated>
Dell(conf-router_bgp)#do sho ip bgp
BGP table version is 31571, local router ID is 172.30.1.57
<output truncated>
AS-PLAIN
Dell(conf-router_bgp)#bgp asnotation asplain
Dell(conf-router_bgp)#sho conf
AS NOTATION DISABLED
Dell(conf-router_bgp)#
no bgp asnotation
Dell(conf-router_bgp)#sho conf
!
router bgp 100
bgp four-octet-as-support
neighbor 172.30.1.250 local-as 65057
<output truncated>
Dell(conf-router_bgp)#do sho ip bgp
BGP table version is 28093, local router ID is 172.30.1.57
AS4 SUPPORT DISABLED
Dell(conf-router_bgp)#no bgp four-octet-as-support
Dell(conf-router_bgp)#sho conf
!
router bgp 100
AS Number Migration
With this feature you can transparently change the AS number of an entire BGP network and ensure that the routes are propagated
throughout the network while the migration is in progress.
When migrating one AS to another, perhaps combining ASs, an eBGP network may lose its routing to an iBGP if the ASN changes.
Migration can be dicult as all the iBGP and eBGP peers of the migrating network must be updated to maintain network reachability.
Essentially, Local-AS provides a capability to the BGP speaker to operate as if it belongs to "virtual" AS network besides its physical
AS network.
The following illustration shows a scenario where Router A, Router B, and Router C belong to AS 100, 200, and 300, respectively.
Router A acquired Router B; Router B has Router C as its customer. When Router B is migrating to Router A, it must maintain the
Border Gateway Protocol IPv4 (BGPv4)
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