Dell Converged Enhanced Ethernet Administrator’s Guide 55
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STP, RSTP, and MSTP configuration and management
6
Enabling Cisco interoperability (MSTP)
In MSTP mode, use this command to enable or disable the ability of the Dell FCoE hardware to
interoperate with certain legacy Cisco switches. If Cisco interoperability is required on any switch in
the network, then all switches in the network must be compatible, and therefore enabled using this
command. The default is Cisco interoperability is disabled.
NOTE
This command is necessary because the “version 3 length” field in the MSTP BPDU on some legacy
Cisco switches does not conform to current standards.
To enable Dell FCoE hardware to interoperate with certain legacy Cisco switches, perform the
following steps from Privileged EXEC mode.
1. Enter the configure terminal command to access global configuration mode.
2. Enter the protocol command to enable MSTP.
switch(config)#protocol spanning-tree mstp
3. Enable the ability of Dell FCoE hardware to interoperate with certain legacy Cisco switches.
switch(conf-mstp)#cisco-interoperability enable
Disabling Cisco interoperability (MSTP)
1. Enter the configure terminal command to access global configuration mode.
2. Enter the protocol command to enable MSTP.
switch(config)#protocol spanning-tree mstp
3. Disable the ability of Dell FCoE hardware to interoperate with certain legacy Cisco switches.
switch(conf-mstp)#cisco-interoperability disable
Mapping a VLAN to an MSTP instance
In MSTP mode, use this command to map a VLAN to an MTSP instance. You can group a set of
VLANs to an instance. This command can be used only after the VLAN is created. VLAN instance
mapping is removed from the configuration if the underlying VLANs are deleted.
To map a VLAN to an MSTP instance, perform the following steps from Privileged EXEC mode.
1. Enter the configure terminal command to access global configuration mode.
2. Enter the protocol command to enable MSTP.
switch(config)#protocol spanning-tree mstp
3. Map a VLAN to an MSTP instance.
switch(conf-mstp)#instance 5 vlan 4096