02-23-2024, 08:28 PM
Correct answer is to configure ebgp multihop on RB. the output of RD shows that ebgp-multihop is configured on RD. See below example of how ebgp multihop is shown in the command output for bpg neighbors.
IOU2(config-router)#do sh run | section router bgp
router bgp 200
bgp log-neighbor-changes
neighbor 1.1.1.1 remote-as 100
IOU2(config-router)#
IOU2(config-router)#do show ip bgp neigh | inc External BGP neighbor
External BGP neighbor not directly connected. <-- multihop not configured
External BGP neighbor configured for connected checks (single-hop no-disable-connected-check)
IOU2(config-router)#
IOU2(config-router)#
IOU2(config-router)#neigh 1.1.1.1 ebgp-multihop 3 <-- Configure Multihop
IOU2(config-router)#
IOU2(config-router)#do show ip bgp neigh | inc External BGP neighbor
External BGP neighbor may be up to 3 hops away. <-- output showing multihop is configured.
External BGP neighbor NOT configured for connected checks (multi-hop no-disable-connected-check)
IOU2(config-router)#
IOU2(config-router)#
IOU2(config-router)#neigh 1.1.1.1 ebgp-multihop 10
IOU2(config-router)#do show ip bgp neigh | inc External BGP neighbor
External BGP neighbor may be up to 10 hops away.
External BGP neighbor NOT configured for connected checks (multi-hop no-disable-connected-check)
IOU2(config-router)#
###example once ebgp multihop is configured on opposite router.
IOU2#sh ip bgp neigh | inc remote router ID
BGP version 4, remote router ID 1.1.1.1
IOU2(config-router)#do sh run | section router bgp
router bgp 200
bgp log-neighbor-changes
neighbor 1.1.1.1 remote-as 100
IOU2(config-router)#
IOU2(config-router)#do show ip bgp neigh | inc External BGP neighbor
External BGP neighbor not directly connected. <-- multihop not configured
External BGP neighbor configured for connected checks (single-hop no-disable-connected-check)
IOU2(config-router)#
IOU2(config-router)#
IOU2(config-router)#neigh 1.1.1.1 ebgp-multihop 3 <-- Configure Multihop
IOU2(config-router)#
IOU2(config-router)#do show ip bgp neigh | inc External BGP neighbor
External BGP neighbor may be up to 3 hops away. <-- output showing multihop is configured.
External BGP neighbor NOT configured for connected checks (multi-hop no-disable-connected-check)
IOU2(config-router)#
IOU2(config-router)#
IOU2(config-router)#neigh 1.1.1.1 ebgp-multihop 10
IOU2(config-router)#do show ip bgp neigh | inc External BGP neighbor
External BGP neighbor may be up to 10 hops away.
External BGP neighbor NOT configured for connected checks (multi-hop no-disable-connected-check)
IOU2(config-router)#
###example once ebgp multihop is configured on opposite router.
IOU2#sh ip bgp neigh | inc remote router ID
BGP version 4, remote router ID 1.1.1.1