Specifications

9-11
Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
OL-26895-01
Chapter 9 Configuring STP
Configuring Spanning-Tree Features
• Configuring Port Priority, page 9-16 (optional)
• Configuring Path Cost, page 9-18 (optional)
• Configuring the Switch Priority of a VLAN, page 9-19 (optional)
• Configuring Spanning-Tree Timers, page 9-20 (optional)
Default Spanning-Tree Configuration
Table 9-3 shows the default spanning-tree configuration.
Spanning-Tree Configuration Guidelines
If more VLANs are defined than there are spanning-tree instances, you can enable PVST+ on STP ports
in only 128 VLANs on the switch. The remaining VLANs operate with spanning tree disabled. However,
you can map multiple VLANs to the same spanning-tree instances by using MSTP. For more
information, see Chapter 10, “Configuring MSTP.”
Table 9-3 Default Spanning-Tree Configuration
Feature Default Setting
Enable state Enabled on NNIs in VLAN 1.
Disabled on ENIs. (Not supported on UNIs)
For more information, see the “Supported Spanning-Tree
Instances” section on page 9-10.
Spanning-tree mode PVST+
PVST+ interoperates with PVST. MSTP is disabled.
Switch priority 32768.
Spanning-tree port priority (configurable on a per-interface basis) 128.
Spanning-tree port cost (configurable on a per-interface basis) 1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
Spanning-tree VLAN port priority (configurable on a per-VLAN
basis)
128.
Spanning-tree VLAN port cost (configurable on a per-VLAN
basis)
1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
Spanning-tree timers Hello time: 2 seconds.
Forward-delay time: 15 seconds.
Maximum-aging time: 20 seconds.