Cisco WS-C2960S-48LPD-L Software Guide - Page 339
MSTP Configuration Guidelines
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Chapter 16 Configuring MSTP Configuring MSTP Features Table 16-4 Default MSTP Configuration (continued) Feature Spanning-tree port priority (configurable on a per-CIST port basis) Spanning-tree port cost (configurable on a per-CIST port basis) Hello time Forward-delay time Maximum-aging time Maximum hop count Default Setting 128. 1000 Mbps: 4. 100 Mbps: 19. 10 Mbps: 100. 2 seconds. 15 seconds. 20 seconds. 20 hops. For information about the supported number of spanning-tree instances, see the "Supported Spanning-Tree Instances" section on page 15-9. MSTP Configuration Guidelines These are the configuration guidelines for MSTP: • When you enable MST by using the spanning-tree mode mst global configuration command, RSTP is automatically enabled. • For two or more switches to be in the same MST region, they must have the same VLAN-to-instance map, the same configuration revision number, and the same name. • The switch supports up to 65 MST instances. The number of VLANs that can be mapped to a particular MST instance is unlimited. • PVST+, rapid PVST+, and MSTP are supported, but only one version can be active at any time. (For example, all VLANs run PVST+, all VLANs run rapid PVST+, or all VLANs run MSTP.) For more information, see the "Spanning-Tree Interoperability and Backward Compatibility" section on page 15-10. For information on the recommended trunk port configuration, see the "Interaction with Other Features" section on page 12-16. • VTP propagation of the MST configuration is not supported. However, you can manually configure the MST configuration (region name, revision number, and VLAN-to-instance mapping) on each switch within the MST region by using the command-line interface (CLI) or through the SNMP support. • For load balancing across redundant paths in the network to work, all VLAN-to-instance mapping assignments must match; otherwise, all traffic flows on a single link. • All MST boundary ports must be forwarding for load balancing between a PVST+ and an MST cloud or between a rapid-PVST+ and an MST cloud. For this to occur, the IST master of the MST cloud should also be the root of the CST. If the MST cloud consists of multiple MST regions, one of the MST regions must contain the CST root, and all of the other MST regions must have a better path to the root contained within the MST cloud than a path through the PVST+ or rapid-PVST+ cloud. You might have to manually configure the switches in the clouds. OL-8603-04 Catalyst 2960 Switch Software Configuration Guide 16-15
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