Cisco Systems 3750E manual Default Mstp Configuration, Mstp Configuration Guidelines, 19-15

Chapter 19 Configuring MSTP

Configuring MSTP Features

Default MSTP Configuration

Table 19-4shows the default MSTP configuration.

Table 19-4	Default MSTP Configuration
Feature		Default Setting
Spanning-tree mode		PVST+ (Rapid PVST+ and MSTP are disabled).
Switch priority (configurable on a per-CIST port basis)		32768.
Spanning-tree port priority (configurable on a per-CIST port basis)		128.
Spanning-tree port cost (configurable on a per-CIST port basis)		1000 Mb/s: 4.
		100 Mb/s: 19.
		10 Mb/s: 100.
Hello time		2 seconds.
Forward-delay time		15 seconds.
Maximum-aging time		20 seconds.
Maximum hop count		20 hops.

For information about the supported number of spanning-tree instances, see the “Supported

Spanning-Tree Instances” section on page 18-10.

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 Catalyst 3560-E 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.

For two or more stacked Catalyst 3750-E 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 Catalyst 3560-E switch supports up to 65 MST instances. The number of VLANs that can be mapped to a particular MST instance is unlimited.

The Catalyst 3750-E switch stack 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 18-11. For information on the recommended trunk port configuration, see the “Interaction with Other Features” section on page 13-20.

•All stack members run the same version of spanning tree (all PVST+, rapid PVST+, or MSTP). For more information, see the “Spanning-Tree Interoperability and Backward Compatibility” section on page 18-11.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		19-15