Cisco Systems 3560X Manual De Usuario
21-15
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 21 Configuring MSTP
Configuring MSTP Features
For information about the supported number of spanning-tree instances, see the
.
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.
is automatically enabled.
•
For two or more Catalyst 3560-X 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.
VLAN-to-instance map, the same configuration revision number, and the same name.
•
For two or more stacked Catalyst 3750-X 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 same VLAN-to-instance map, the same configuration revision number, and the same name.
•
The Catalyst 3560-X switch supports up to 65 MST instances. The number of VLANs that can be
mapped to a particular MST instance is unlimited.
mapped to a particular MST instance is unlimited.
•
The Catalyst 3750-X switch stack supports up to 65 MST instances. The number of VLANs that can
be mapped to a particular MST instance is unlimited.
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
example, all VLANs run PVST+, all VLANs run rapid PVST+, or all VLANs run MSTP.) For more
information, see the
•
All stack members run the same version of spanning tree (all PVST+, rapid PVST+, or MSTP). For
more information, see the
more information, see the
•
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.
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. You can achieve
load-balancing across a switch stack by manually configuring the path cost.
assignments must match; otherwise, all traffic flows on a single link. You can achieve
load-balancing across a switch stack by manually configuring the path cost.
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.
Table 21-4
Default MSTP Configuration (continued)
Feature
Default Setting