The following example shows viewing the debug log of a successful MSTP configuration.Dell#debug spanning-tree mstp bpduMSTP debug bpdu is ONDell#4w0d4h : MSTP: Sending BPDU on Te 2/21 :ProtId: 0, Ver: 3, Bpdu Type: MSTP, Flags 0x6eCIST Root Bridge Id: 32768:0001.e806.953e, Ext Path Cost: 0Regional Bridge Id: 32768:0001.e806.953e, CIST Port Id: 128:470Msg Age: 0, Max Age: 20, Hello: 2, Fwd Delay: 15, Ver1 Len: 0, Ver3 Len: 96Name: Tahiti, Rev: 123, Int Root Path Cost: 0Rem Hops: 20, Bridge Id: 32768:0001.e806.953e4w0d4h : INST 1: Flags: 0x6e, Reg Root: 32768:0001.e806.953e, Int Root Cost: 0Brg/Port Prio: 32768/128, Rem Hops: 20INST 2: Flags: 0x6e, Reg Root: 32768:0001.e806.953e, Int Root Cost: 0Brg/Port Prio: 32768/128, Rem Hops: 204w0d4h : MSTP: Received BPDU on Te 2/21 :ProtId: 0, Ver: 3, Bpdu Type: MSTP, Flags 0x78 (Indicates MSTP routers are in the [single]region.)CIST Root Bridge Id: 32768:0001.e806.953e, Ext Path Cost: 0Regional Bridge Id: 32768:0001.e806.953e, CIST Port Id: 128:470Msg Age: 0, Max Age: 20, Hello: 2, Fwd Delay: 15, Ver1 Len: 0, Ver3 Len: 96Name: Tahiti, Rev: 123 (MSTP region name and revision), Int Root Path Cost: 0Rem Hops: 19, Bridge Id: 32768:0001.e8d5.cbbd4w0d4h : INST 1 (MSTP Instance): Flags: 0x78, Reg Root: 32768:0001.e806.953e, Int RootCost: 0Brg/Port Prio: 32768/128, Rem Hops: 19INST 2 (MSTP Instance): Flags: 0x78, Reg Root: 32768:0001.e806.953e, Int Root Cost: 0Brg/Port Prio: 32768/128, Rem Hops: 19Indicates MSTProuters are in the(single) regionMSTP InstanceMSTP Region nameThe following example shows viewing the debug log of an unsuccessful MSTP configuration.4w0d4h : MSTP: Received BPDU on Te 2/21 :ProtId: 0, Ver: 3, Bpdu Type: MSTP, Flags 0x78Different Region (Indicates MSTP routers arein different regions and are not communicating with each other.)CIST Root Bridge Id: 32768:0001.e806.953e, Ext Path Cost: 0Regional Bridge Id: 32768:0001.e806.953e, CIST Port Id: 128:470Msg Age: 0, Max Age: 20, Hello: 2, Fwd Delay: 15, Ver1 Len: 0, VerName: Tahiti, Rev: 123, Int Root Path Cost: 0Rem Hops: 20, Bridge Id: 32768:0001.e8d5.cbbd4w0d4h : INST 1: Flags: 0x70, Reg Root: 32768:0001.e8d5.cbbd, IntBrg/Port Prio: 32768/128, Rem Hops: 20INST 2: Flags: 0x70, Reg Root: 32768:0001.e8d5.cbbd, Int Root CostBrg/Port Prio: 32768/128, Rem Hops: 20556 Multiple Spanning Tree Protocol (MSTP)
