Default Rstp And Mstp Configuration; Rstp And Mstp Configuration Guidelines - Cisco Catalyst 2950 Software Configuration Manual

Configuring RSTP and MSTP Features

Default RSTP and MSTP Configuration

Table 11-3
Table 11-3 Default RSTP and MSTP Configuration
Feature
Spanning-tree mode
Switch priority (configurable on a per-CIST interface basis)
Spanning-tree port priority (configurable on a per-CIST interface basis)
Spanning-tree port cost (configurable on a per-CIST interface basis)
Hello time
Forward-delay time
Maximum-aging time
Maximum hop count

RSTP and MSTP Configuration Guidelines

These are the configuration guidelines for RSTP and MSTP:
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Catalyst 2950 Desktop Switch Software Configuration Guide
11-12
shows the default RSTP and MSTP configuration.
The UplinkFast, BackboneFast, and cross-stack UplinkFast features are not supported with the
RSTP and MSTP.
Per-VLAN RSTP is not supported. When you enable MST by using the spanning-tree mode mst
global configuration command, RSTP is enabled.
PVST, PVST+ and MSTP are supported, but only one version can be active at any time; all VLANs
run PVST, or all VLANs run MSTP.
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. For this to happen, 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 with the MST cloud
than a path through the PVST+ cloud. You might have to manually configure the switches in the
clouds.
Partitioning the network into a large number of regions is not recommended. However, if this
situation is unavoidable, we recommend that you partition the switched LAN into smaller LANs
interconnected by routers or non-Layer 2 devices.
Chapter 11 Configuring RSTP and MSTP
Default Setting
PVST (MSTP and RSTP are disabled).
32768.
128.
1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
2 seconds.
15 seconds.
20 seconds.
20 hops.
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