Initial Establishment of Active/ Standby VSR-NRC Roles

The initial establishment of active/standby VSR-NRC roles is as follows.
  1. NRC-P performs up to 3 attempts at 10-second intervals to establish the global CPROTO channel to the primary VSR-NRC (for example, VSR-NRC-A in the primary site). If not successful, it performs another 3 attempts to the secondary VSR-NRC (VSR-NRC-B in primary site). This process is continued cycling among the two VSR-NRCs until the global channel is established to either VSR-NRC-A or VSR-NRC-B which then becomes the target active VSR-NRC. The CPROTO channel establishment attempts continue to the other VSR-NRC which becomes the target standby VSR-NRC.

    This CPROTO channel establishment process is also followed when the global CPROTO channel to the active VSR-NRC goes down beginning always with an attempt to the primary VSR-NRC (VSR-NRC-A) and then onto the secondary VSR-NRC (VSR-NRC-B) and continuing to cycling between them until a channel is established.

  2. At successful global CPROTO channel establishment, the NRC-P sends a notify message (wscIsActive=TRUE, mateAddr, matePort) requesting a transition to active role from the VSR-NRC (VSR-NRC-A or VSR-NRC-B).
  3. When NRC-P also established the TOPO and PCEP CPROTO channels, the active VSR-NRC begins the partial database synchronization procedures to NRC-P, as mentioned in TE-DB and LSP-DB Partial Synchronization.
  4. When the reconcile process is complete, the active VSR-NRC acknowledges the NRC-P by sending a notify reply message (notifyReply=TRUE).
  5. The active VSR-NRC attempts to establish a CPROTO sync channel to the mate VSR-NRC. After it is successfully established, it begins the full or partial database synchronization procedures to the mate VSR-NRC following the procedures, as mentioned in TE-DB and LSP-DB Partial Synchronization.
  6. After the global CPROTO channel to the target standby VSR-NRC is established, NRC-P sends a notify message (wscIsActive=FALSE, mateAddr, matePort) requesting transition to a standby role. The target standby VSR-NRC acknowledges by sending a notify reply message (notifyReply=TRUE). No database synchronization occurs between the standby VSR-NRC and the NRC-P.
  7. The standby VSR-NRC maintains a copy of the mate active VSR-NRC database and independently builds its own database using BGP-LS and PCEP peerings with the network.
  8. When the active and standby roles have been assigned by the NRC-P, the primary and secondary VSR-NRCs keep that role until further notice from NRC-P. The roles are not affected by the state of the CPROTO sync channel.
Parent topic: VSR-NRC 1+1 Single-Site Redundancy