Default Mst Configuration; Mst Configuration Guidelines And Restrictions - Cisco 7604 Configuration Manual

Configuring MST
•
•
•
•
•
•

Default MST Configuration

Table 19-4
Table 19-4 Default MST Configuration
Feature
spanning tree mode
Switch priority (configurable on a per-CIST port basis)
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

MST Configuration Guidelines and Restrictions

When configuring MST, follow these guidelines and restrictions:
•
•
•
•
•
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
19-16
Configuring the Transmit Hold Count, page 19-25
Configuring the Maximum-Aging Time, page 19-26
Configuring the Maximum-Hop Count, page 19-26
Specifying the Link Type to Ensure Rapid Transitions, page 19-26
Designating the Neighbor Type, page 19-27
Restarting the Protocol Migration Process, page 19-28
shows the default MST configuration.
The 802.1s MST standard allows up to 65 MST instances. You can map an unlimited number of
VLANs to an MST instance.
PVST+, rapid PVST+, and MST are supported, but only one version can be active at any time.
VTP does not propagate the MST configuration. You must manually configure the MST
configuration (region name, revision number, and VLAN-to-instance mapping) on each router
within the MST region through the command-line interface (CLI) or SNMP.
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 CIST regional root of the
MST cloud must 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.
Chapter 19 Configuring Standard-Compliant IEEE MST
(optional)
(optional)
(optional)
(optional)
(optional)
(optional)
Default Setting
PVST+ (Rapid PVST+ and MST are disabled)
32768
128
1000 Mbps: 4
100 Mbps: 19
10 Mbps: 100
2 seconds
15 seconds
20 seconds
20 hops
OL-4266-08