Default Stp And Rstp Configuration; Disabling Stp And Rstp; Table 6-5 Default Stp And Rstp Configuration - Cisco ONS 15454 Software Feature And Configuration Manual

Default STP and RSTP Configuration

Default STP and RSTP Configuration

Table 6-5
Table 6-5
Feature
Enable state
Switch priority
Spanning-tree port priority (configurable on a per-interface
basis—used on interfaces configured as Layer 2 access ports)
Spanning-tree port cost (configurable on a per-interface basis) 1000 Mbps: 4
Hello time
Forward-delay time
Maximum-aging time

Disabling STP and RSTP

STP is enabled by default on VLAN 1 and on all newly created VLANs up to the specified spanning-tree
limit of 255. Disable STP only if you are sure there are no loops in the network topology.
STP edge ports are bridge ports that do not need STP enabled, where loop protection is not needed out
Caution
of that port or an STP neighbor does not exist out of that port. For RSTP, it is important to disable STP
on edge ports, which are typically front-side Ethernet ports, using the command bridge
bridge-group-number spanning-disabled on the appropriate interface. If RSTP is not disabled on edge
ports, convergence times will be excessive for packets traversing those ports.
When STP is disabled and loops are present in the topology, excessive traffic and indefinite packet
Caution
duplication can drastically reduce network performance.
Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
6-16
shows the default STP and RSTP configuration.
Default STP and RSTP Configuration
Chapter 6 Configuring STP and RSTP
Default Setting
Up to 255 spanning-tree instances
can be enabled.
32768 + Bridge ID
128
100 Mbps: 19
10 Mbps: 100
STS-1: 37
STS-3c: 14
STS-6c: 9
STS-9c: 7
STS-12c: 6
STS-24c: 3
2 seconds
15 seconds
20 seconds
January 2004