Cisco Cisco 1 10 100 Ethernet 2 WAN Card Slot Network Module White Paper
© 2012 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information.
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If there is a misconfiguration in switch IDs (when both switches have the same switch ID), the formation of the VSL
will fail on initialization. When the two chassis are being brought up as a single Cisco Virtual Switching System, the
VSL initialization handshake verifies that the switch IDs of the two chassis do not match. If the switch ID is found to
be in conflict, the VSL will not become active. If this situation occurs, both chassis assume the role of active virtual
switch and you are informed of this conflict.
Conversion to Virtual Switch Mode
This section details the steps required to convert a standalone system into virtual switch mode. The interfaces
forming the VSL should be connected prior to the conversion process, to minimize the number of times the chassis
is reloaded. Additionally, you should begin the conversion process using a default configuration, as the conversion
process removes any previous configuration that exists on the standalone chassis. Refer to Figure 11 to reference
the conversion process.
Figure 11. Cisco Virtual Switching System Conversion
Step 1. Configure virtual switch ID and domain.
On the two switches, configure the same virtual
switch domain number (in this case it is 100), but
unique switch IDs using the following configuration
mode commands:
switch domain number (in this case it is 100), but
unique switch IDs using the following configuration
mode commands:
VSS-sw1#conf t
Enter configuration commands, one per
line. End with CNTL/Z.
VSS-sw1(config)#switch virtual domain
100
Domain ID 100 config will take effect
only
line. End with CNTL/Z.
VSS-sw1(config)#switch virtual domain
100
Domain ID 100 config will take effect
only
after the exec command ‘switch convert
mode virtual’ is issued
mode virtual’ is issued
VSS-sw1(config-vs-domain)#switch 1
VSS-sw1(config-vs-domain)#
VSS-sw2#conf t
Enter configuration commands, one per
line. End with CNTL/Z.
VSS-sw2(config)#switch virtual domain
100
Domain ID 100 config will take effect
only
line. End with CNTL/Z.
VSS-sw2(config)#switch virtual domain
100
Domain ID 100 config will take effect
only
after the exec command ‘switch convert
mode virtual’ is issued
mode virtual’ is issued
VSS-sw2(config-vs-domain)#switch 2
VSS-sw2(config-vs-domain)#
Note that as a result of this command, the domain ID is retained in the configuration, but the switch ID is not; this
value is stored as a variable in ROMmon. It can be confirmed by issuing the following command on each switch:
VSS-sw1#switch read switch_num
Read switch_num
from rommon is 1
VSS-sw2#switch read switch_num
Read switch_num from rommon is 2