Cisco MDS 9000 Series Configuration Guide

Number of CSWR RJT sent = 0
Number of CSWR RJT not sent = 0
RSCN Timer Configuration Distribution Using CFS
Because the timeout value for each switch is configured manually, a misconfiguration occurs when different
switches time out at different times. This means different N ports in a network can receive RSCNs at different
times. Cisco Fabric Services (CFS) alleviates this situation by automatically distributing configuration
information to all switches in a fabric. This also reduces the number of SW-RSCNs.
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.
All configuration commands are not distributed. Only the rscn event-tov tov vsan vsan command is distributed.
Note
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.
Before performing a downgrade, make sure that you revert the RCSN timer value in your network to the
default value. Failure to do so will disable the links across your VSANs and other devices.
Note
Compatibility across various Cisco MDS NX-OS releases during an upgrade or downgrade is supported by
conf-check provided by CFS. If you attempt to downgrade from Cisco MDS SAN-OS Release 3.0, you are
prompted with a conf-check warning. You are required to disable RSCN timer distribution support before
you downgrade.
By default, the RSCN timer distribution capability is disabled and is therefore compatible when upgrading
from any Cisco MDS SAN-OS release earlier than Release 3.0.
Configuring the RSCN Timer
RSCN maintains a per-VSAN event list queue, where the RSCN events are queued as they are generated.
When the first RSCN event is queued, a per VSAN timer starts. Upon time-out, all the events are dequeued
and coalesced RSCNs are sent to registered users. The default timer values minimize the number of coalesced
RSCNs sent to registered users. Some deployments require smaller event timer values to track changes in the
fabric.
The RSCN timer value must be the same on all switches in the VSAN. See the RSCN Timer Configuration
Distribution, on page 234.
Note
Before performing a downgrade, make sure that you revert the RCSN timer value in your network to the
default value. Failure to do so will disable the links across your VSANs and other devices.
Note
Cisco MDS 9000 Series Fabric Configuration Guide, Release 8.x
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Managing FLOGI, Name Server, FDMI, and RSCN Databases
RSCN Timer Configuration Distribution Using CFS

Cisco MDS 9000 Series Specifications

General

Category	Switch
Operating System	Cisco NX-OS
Ports	Varies by model
Protocols	Fibre Channel (FC), Fibre Channel over IP (FCIP), iSCSI
Redundancy	Redundant supervisors, power supplies, and fans
Management	Cisco Data Center Network Manager (DCNM), CLI, SNMP
Virtualization Support	VSANs (Virtual SANs)
Security Features	Fibre Channel Security Protocol (FC-SP)
Hot Swappable Components	power supplies, fans
Power Supply Options	AC and DC options available