What happens when the Hold Time parameter between BGP peers is set to 0?

When the Hold Time parameter between BGP peers is set to 0, it indicates that no Keepalive messages will be sent. The Hold Time in BGP is used to determine how long a peer will wait before considering the connection to be down if no messages are received. Setting this value to 0 effectively disables the function of sending periodic Keepalive messages, which are meant to maintain the session by assuring each peer that the other is still active and reachable.

As a result, when both peers have Hold Time set to 0, they will not transmit Keepalive messages, which means that the BGP session could potentially go down quickly if no updates or notifications are exchanged. This typically leads to disconnection after the initial Open message is sent, as there will be no further communication to sustain the session.

This behavior emphasizes the importance of configuration choices in BGP, as it can affect the stability and reliability of routing sessions between peers.