Cisco 6503 White Paper page 4

Example 2: Classic and Fabric-Enabled System
The following output is from a configuration with dual supervisor engines, one SFM, one classic line card in slot 3, and two
fabric-enabled line cards in slots 7 and 9.
Sup-A> (enable) show fabric channel switchmode
Module Num Fab Chan Fab Chan Switch Mode
------ ------------ -------- ------------ --------------
1 1 0, 0 flow through ok
2 1 0, 1 truncated
3 0 n/a n/a
5 18 0, 0 n/a
5 18 1, 1 n/a
5 18 2, 2 n/a
5 18 3, 3 n/a
5 18 4, 4 n/a
5 18 5, 5 n/a
5 18 6, 6 n/a
5 18 7, 7 n/a
5 18 8, 8 n/a
5 18 9, 9 n/a
5 18 10, 10 n/a
5 18 11, 11 n/a
5 18 12, 12 n/a
5 18 13, 13 n/a
5 18 14, 14 n/a
5 18 15, 15 n/a
5 18 16, 16 n/a
5 18 17, 17 n/a
7 1 0, 6 truncated
9 1 0, 8 truncated
15 0 n/a n/a
16 0 n/a n/a
Automatic switching mode changes allow the acceptance of classic or fabric-enabled cards into a system with no manual
configuration change. As previously stated, there is a performance versus interoperability tradeoff when installing classic line
cards into a fabric-enabled system. Because many network environments hold performance in higher regard, a fabric-enabled
system can be configured to reject classic cards (for example, not support flow-through mode). By issuing the set system
crossbar-fallback none command, the system will not start classic line cards installed in the chassis, thereby running in
compact switching mode (30 Mpps) only.
Sup-A> (enable) set system crossbar-fallback none
The default for the crossbar-fallback is bus mode. To determine the current system state, the show system crossbar-fallback
command is available.
Sup-A> (enable) show system crossbar-fallback
Cross-fallback: bus-mode
In summary, the SFM can be redundantly configured in a chassis to provide fabric-to-fabric and fabric-to-bus failover. A
system configured with dual SFMs can use the standby SFM for failover. Additionally, single SFM systems with
fabric-enabled line cards can fail over to the 32-Gbps bus for continuous operation. In both of these scenarios, recovery and
return to normal operation occur in less than three seconds. This quick recovery time allows for a switching mode change and
a synchronization process that must take place between each line card, supervisor engine, and the SFM fabric channels in these
scenarios. The capability to configure redundant SFMs provides up to three levels of backplane redundancy, helping to enable
continuous operations with minimal impact to network availability in the event of a hardware failure.
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Channel Status
ok
n/a
ok
ok
unknown
unknown
unknown
unknown
ok
unknown
ok
unknown
unknown
unknown
unknown
unknown
unknown
unknown
unknown
unknown
ok
ok
n/a
n/a
Cisco Systems, Inc.
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