On an S series switch, after the reset bgp ipv4-address command is executed to reset BGP connections using the IPv4 unicast address family, why is the connection of BGP peers using the VPNv4 address family terminated

9

Q: After the reset bgp ipv4-address command is executed to reset the BGP connection of the unicast address family, why is the BGP connection of the same peers in the VPNv4 address family cut off?

A: If the peers of two address families have the same addresses, the two address families share the same BGP session, that is, the same TCP connection. If one of the BGP connections is reset, the other is disconnected.

Other related questions:
Why are BGP connections reestablished after the peer connect-interface command is executed on S series switches
Currently, S series switches do not support BGP dynamic capability negotiation. Therefore, when capabilities of the BGP neighbor are changed, the BGP connection is automatically cut off and then the capabilities of the neighbor are renegotiated. If the peer connect-interface command is configured, the BGP session needs to be set up by designating the egress. Therefore, the source address of the TCP connection may be changed and the TCP connection needs to be re-established by using the new source address.

Why are loopback addresses used to establish BGP peer relationships
Loopback interfaces are logical interfaces. Compared with physical interfaces, loopback interfaces are not affected by links and can reduce the Border Gateway Protocol (BGP) flapping.

For S series switches, why is the BGP connection not immediately closed after the shutdown command is executed on the interfaces connecting two peers
Q: Why is the BGP connection not cut off immediately after the shutdown command is executed on interfaces connecting two devices? A: When the EBGP peers are directly connected and the ebgp-interface-sensitive command is executed in the BGP view, the BGP peer connection is interrupted immediately after the interfaces connecting the two peers are shut down. By default, the ebgp-interface-sensitive command is executed in the BGP view. In other cases, the BGP peer relationship is not interrupted until the Hold timer times out.

Why are BGP connections re-established after the peer connect-interface command is configured
Currently, the switch does not support BGP dynamic capability negotiation. Therefore, if certain capabilities of the BGP peer are changed, the BGP connection is automatically disconnected and then the capabilities of the neighbor are renegotiated. If the peer connect-interface command is configured, the BGP session needs to be set up by designating the egress. Therefore, the source address of the TCP connection may be changed and the TCP connection needs to be re-established by using the new source address.

What are the advantages of using the loopback address to establish BGP peer relationship
The loopback interface is a logical interface. Generally, it is in the Up state and is less affected by links than physical interfaces.

If you have more questions, you can seek help from following ways:
To iKnow To Live Chat
Scroll to top