> # RSCN Timer Configuration Distribution

> Because the timeout value for each switch is configured manually, a misconfiguration occurs when different switches time out at different times. This means different Nports in a network can receive RSCNs at different times. Cisco Fabric Services (CFS) infrastructure alleviates this situation by automatically distributing the RSCN timer configuration information to all switches in a fabric. This action also reduces the number of SW-RSCNs. Refer to the Cisco MDS 9000 Family NX-OS System Management Configuration Guide.

> RSCN supports two modes, distributed and nondistributed. In distributed mode, RSCN uses CFS to distribute configuration to all switches in the fabric. In nondistributed mode, only the configuration commands on the local switch are affected.

> Note All configuration commands are not distributed. Only the rscn event-tov tov vsan vsan command is distributed.

> Note Only the RSCN timer configuration is distributed.

> The RSCN timer is registered with CFS during initialization and switchover. For high availability, if the RSCN timer distribution crashes and restarts or a switchover occurs, it resumes normal functionality from the state prior to the crash or switchover.

> Note You can determine the compatibility when downgrading to an earlier Cisco MDS NX-OS release using show incompatibility system command. You must disable RSCN timer distribution support before downgrading to an earlier release.

> Note By default, the RSCN timer distribution capability is disabled and is compatible when upgrading from any Cisco MDS SAN-OS release earlier than 3.0.

> Note For CFS distribution to operate correctly for the RSCN timer configuration, all switches in the fabric must be running Cisco SAN-OS Release 3.0(1) or later, or Cisco NX-OS 4.1(1b).

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