CCR-T replay and multi-chassis redundancy

The first CCR-T reply for each Gx session is synchronized, but the consecutive CCR-T replays for the same Gx sessions are not synchronized. When the answer (CCA-t) is received, the CCR-T replay is terminated and this event (deletion of CCR-T replay) is synchronized to the other node.

CCR-T replays are sent from the node that was in SRRP active state at the time when the CCR-T was initiated. They continue to be sent from the same node even if the SRRP is switched over in the meantime.

This entire process can be thought of as if the CCR-T initiating node (active SRRP) armed its MCS peer with CCR-T replay for a Gx session. This occurs at the very beginning, when a CCR-T replay is first initiated for a Gx session. The armed node stays silent until the MCS peer that is actively sending CCR-T replays for a Gx session, reboots. Only when the MCS peer reboots, the armed node starts sending CCR-T replays for a Gx session in the following fashion: first message is sent with cleared T-bit, followed by replays at the configured replay interval and a fresh 24 hour lifetime.