LDP NSR
To use LDP nonstop routing (NSR), the device must have a minimum of two MPUs.
LDP NSR backs up protocol states and data (including LDP session and LSP information) from the active process to the standby process. When the LDP active process fails, the standby process becomes active and takes over processing seamlessly. The LDP peers are not notified of the LDP interruption. The LDP session stays in Operational state, and the forwarding is not interrupted.
The LDP active process fails when one of the following situations occurs:
The active process restarts.
The MPU where the active process resides fails.
The MPU where the active process resides performs an ISSU.
The LDP process' position determined by the process placement feature is different from the position where the LDP process is operating.