BROCADE IP PRIMER

IEEE 802.1d (Spanning Tree Protocol)Notice that this setting was not entered at the Interface Config level, but theGlobal config level.These next three commands configure STP timers. Use these with a great dealof caution. Know what you are doing when you change these settings, especiallywhen interacting with switches from other manufacturers. Know that allof your participants in the infrastructure are going to be expecting STPdefaults. Because of this, tampering with the default settings may cause networkinstability. Use at your own risk.• Forward-delay. This is the time an interface will stay in the Listening andLearning states. By default, this is 15 seconds, as we discussed earlier.The timer for Listening and Learning will always be equal, so the numberis only set once. Here's an example of the command you would use tochange the forward-delay timer to 10 seconds (speeding up convergencefrom 30 seconds to 20 seconds):Switch(config)#spanning-tree forward-delay 10• Hello-time. The root switch sends BPDUs to all other switches every twoseconds, by default. This is the hello-time. Let's say, for some reason,you'd like to change this to five seconds:Switch(config)#spanning-tree hello-time 5• Max-age. This is the amount of time a non-root switch will wait before itdecides the root switch is dead and call for a re-election. By default, anon-root switch will wait for 20 seconds. This timer is configured on theroot switch. In other words, the root switch will dictate how long the otherswitches should wait before declaring him dead. This command changesthe advertised “max-age” to 45 seconds:Switch(config)#spanning-tree max-age 45By far, the handiest of STP commands are those that help you troubleshootproblems; the commands that show you how things actually are. The standard?Take a guess:Switch#show spanning-treeSTP instance owned by VLAN 1Global STP (IEEE 802.1D) Parameters:VLAN Root Root Root Prio Max He- Ho- Fwd Last Chg BridgeID ID Cost Port rity Age llo ld dly Chang cnt AddressHex sec sec sec sec sec1 8000000abc123c00 4 1 8000 20 2 1 15 3499283 0000abc4321a0Port STP Parameters:Port Prio Path State Fwd Design DesignatedDesignatedNum rity Cost Trans Cost Root BridgeHex1 80 4 FORWARDING 1 0 8000000abc123c00 8000000abc123c002 80 4 BLOCKING 0 0 8000000abc123c00 8000000abc123c00Brocade IP Primer 201