Two connected routers are configured with BGP. The physical port and protocol of the two routers are in normal state. The two routers can ping each other. However, the BGP peer relationship fails to be established.
[RouterA] bgp 65080
[RouterA-bgp] peer 10::1 as-number 65081
[RouterA-bgp-af-ipv6] peer 10::1 enable
[RouterB] bgp 65081
[RouterB-bgp] peer 10::1 as-number 65080
[RouterB-bgp-af-ipv6] peer 10::2 enable
On an IPv4 network, the router ID is not specified in the BGP view. BGP automatically selects an interface IP address as the router ID. On an IPv6 network where the router ID is still a 32-bit value, if the router ID is not specified while no interface has an IPv4 address on the network, BGP negotiation fails due to the lack of the router ID.
BGP negotiation fails due to the lack of a 32-bit router ID.