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

Chapter 20 Configuring STP and Prestandard IEEE 802.1s MST

Default STP Configuration

Table 20-5
Table 20-5 STP Default Configuration
Feature
Enable state
Bridge priority
STP port priority (configurable on a per-port
basis—used on LAN ports configured as
Layer 2 access ports)
STP port cost (configurable on a per-port
basis—used on LAN ports configured as
Layer 2 access ports)
STP VLAN port priority (configurable on a
per-VLAN basis—used on LAN ports
configured as Layer 2 trunk ports)
STP VLAN port cost (configurable on a
per-VLAN basis—used on LAN ports
configured as Layer 2 trunk ports)
Hello time
Forward delay time
Maximum aging time
Mode

STP and MST Configuration Guidelines and Restrictions

When configuring MST, follow these guidelines and restrictions:
•
•
•
•
•
•
OL-4266-08
shows the default STP configuration.
Do not disable spanning tree on any VLAN in any of the PVST bridges.
Do not use PVST bridges as the root of CST.
Ensure that all PVST spanning tree root bridges have lower (numerically higher) priority than the
CST root bridge.
Ensure that trunks carry all of the VLANs mapped to an instance or do not carry any VLANs at all
for this instance.
Do not connect switches with access links because access links may partition a VLAN.
Any MST configuration involving a large number of either existing or new logical VLAN ports
should be completed during a maintenance window because the complete MST database gets
reinitialized for any incremental change (such as adding new VLANs to instances or moving VLANs
across instances).
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
Default Value
STP enabled for all VLANs
32768
128
10-Gigabit Ethernet: 2
•
Gigabit Ethernet: 4
•
Fast Ethernet: 19
•
• Ethernet: 100
128
• 10-Gigabit Ethernet: 2
• Gigabit Ethernet: 4
• Fast Ethernet: 19
Ethernet: 100
•
2 seconds
15 seconds
20 seconds
PVST
Default STP Configuration
20-21