When two routers establish a logical BGP peer relationship over multiple links, is the use of the peer connect-interface command mandatory?

In Border Gateway Protocol (BGP), establishing a logical peer relationship between two routers is crucial for ensuring proper communication and route advertisement. When multiple links are present between routers, specifying the peer connect-interface is not inherently mandatory, but it is highly recommended for clarity in network design and operation.

Using the peer connect-interface command allows administrators to explicitly define which interface or link should be used for establishing the BGP session. This becomes particularly important in environments with multiple links, as it helps avoid potential routing issues and simplifies troubleshooting by clearly indicating the path for BGP traffic. If this command is not used, the routers might choose a path arbitrarily, which can lead to unstable connections or inconsistent routing behaviors.

By defining the specific interface for BGP peering, administrators can also optimize performance and ensure that the BGP session is resilient against failures by allowing for backup paths or interfaces. Therefore, while there may be scenarios where BGP can establish connectivity without this command, its usage enhances the reliability and predictability of the BGP peering process in complex network topologies. This is why the statement regarding the mandatory use of the peer connect-interface command is considered true in this context.