Overview

The synchronization process provides the means to manage distributed database (the Multi-Chassis Synchronization (MCS) database), which contains the dynamic state information created on any of the nodes by any application using its services. The individual entries in the MCS database are always paired by peering-relation, sync-tag and application-id. At any time the specified entry is related to the single redundant-pair objects (two SAPs on two different nodes) and therefore stored in a local MCS database of the respective nodes.

Internally, peering-relation and sync-tag are translated into a port and encapsulation value identifying the object (SAP) that the specified entry is associated with. The application-id then identifies the application which created the entry on one of the nodes. There are three basic operations that the application can perform on MCS database. The MCS database always synchronizes these operations with its respective peer for the specified entry.

The following principles apply:

The choice of the operation in corresponding situation is driven by the application. The following general guidelines are observed:

As previously stated, the MCS process automatically synchronizes any database operation with the corresponding peer. During this time, the MCS process maintains state per peer indicating to the applications (and network operator) the current status, such as in-sync, synchronizing or sync_down. These states are indicated by corresponding traps.