Dell Force10 MXL Blade MXL 10/40GbE Switch IO Module Configuration Guide - Page 353

Debugging and Verifying an MSTP Configuration To display BPDUs, use the debug spanning-tree mstp bpdu command from EXEC Privilege mode (Figure 19-15). To display MSTP-triggered topology change messages, use the debug spanning-tree mstp events command. Figure 19-15. Displaying BPDUs and Events FTOS#debug spanning-tree mstp bpdu 1w1d17h : MSTP: Sending BPDU on TenGig 1/31 : ProtId: 0, Ver: 3, Bpdu Type: MSTP, Flags 0x68 CIST Root Bridge Id: 32768:0001.e806.953e, Ext Path Cost: 20000 Regional Bridge Id: 32768:0001.e809.c24a, CIST Port Id: 128:384 Msg Age: 2, Max Age: 20, Hello: 2, Fwd Delay: 15, Ver1 Len: 0, Ver3 Len: 96 Name: my-mstp-region, Rev: 0, Int Root Path Cost: 20000 Rem Hops: 19, Bridge Id: 32768:0001.e80d.b6d6 E1200#1w1d17h : INST 1: Flags: 0x28, Reg Root: 32768:0001.e809.c24a, Int Root Co Brg/Port Prio: 32768/128, Rem Hops: 19 INST 2: Flags: 0x68, Reg Root: 4096:0001.e809.c24a, Int Root Cost: 20000 Brg/Port Prio: 32768/128, Rem Hops: 19 [output omitted] FTOS#debug spanning-tree mstp events 1w1d17h : MSTP: TC flag set in the incoming BPDU on port TenGig 1/31 for instance 0 1w1d17h : MSTP: TC flag set in the incoming BPDU on port TenGig 1/31 for instance 0 1w1d17h : MSTP: TC flag set in the incoming BPDU on port TenGig 1/31 for instance 0 Examine your individual routers to ensure all the necessary parameters match. 1. Region Name 2. Region Version 3. VLAN to Instance mapping The show spanning-tree mst commands show various portions of the MSTP configuration. To view the overall MSTP configuration on the router, use the show running-configuration spanning-tree mstp command in EXEC Privilege mode (Figure 19-16). To monitor and verify that the MSTP configuration is connected and communicating as desired, use the debug spanning-tree mstp bpdu command (Figure 19-17). Key items to look for in the debug report: • MSTP flags indicate communication received from the same region. • In Figure 19-17, the output shows that the MSTP routers are located in the same region. • Does the debug log indicate that packets are coming from a "Different Region" (Figure 19-18)? If so, one of the key parameters is not matching. • MSTP Region Name and Revision • The configured name and revisions must be identical among all the routers. • Is the Region name blank? That may mean that a name was configured on one router and but was not configured or was configured differently on another router (spelling and capitalization counts). Multiple Spanning Tree Protocol (MSTP) | 351