Optional-Spanning-tree-Features_2
StartFragment STP BPDU Filter
・Filter BPDUs in and out
Verification
SW2
・e0/1 shut ・e0/0 L3 routed port IP address:169.254.24.2 /24 SW4
・e0/1 access port VLAN 10 BPDU filter SW2(config)#int e0/1 SW2(config-if)#shut SW2#sh ip int bri Interface IP-Address OK? Method Status Protocol Ethernet0/0 169.254.24.2 YES manual up up Ethernet0/1 unassigned YES unset administratively down down SW4(config)#int e0/1 SW4(config-if)#shut SW4(config)#default int e0/0 SW4(config)#int e0/0 SW4(config-if)#shut SW4(config-if)#switchport access vlan 10 SW4(config-if)#switchport mode access SW4(config-if)#spanning-tree bpdufilter enable SW4(config-if)#no shut SW4#sh span vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 4106 Address aabb.cc00.0100 Cost 200 Port 5 (Ethernet1/0) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 8202 (priority 8192 sys-id-ext 10) Address aabb.cc00.0400 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 15 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 100 128.1 Shr Et1/0 Root FWD 100 128.5 Shr Et1/1 Altn BLK 100 128.6 Shr SW4#sh span int e0/0 detail Port 1 (Ethernet0/0) of VLAN0010 is designated forwarding Port path cost 100, Port priority 128, Port Identifier 128.1. Designated root has priority 4106, address aabb.cc00.0100 Designated bridge has priority 8202, address aabb.cc00.0400 Designated port id is 128.1, designated path cost 200 Timers: message age 0, forward delay 0, hold 0 Number of transitions to forwarding state: 1 Link type is shared by default Bpdu filter is enabled
BPDU: sent 0, received 0
SW2 doesn't send BPDU on e0/0, so VLAN 10 doen't have a loop.
Change SW2 e0/0 L2 switch port, access vlan 10. SW2(config)#default int e0/0 SW2(config)#int e0/0 SW2(config-if)#switchport access vlan 10 SW2(config-if)#switchport mode access SW2#sh span vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 4106 Address aabb.cc00.0100 Cost 100 Port 5 (Ethernet1/0) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 16394 (priority 16384 sys-id-ext 10) Address aabb.cc00.0200 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 100 128.1 Shr Et1/0 Root FWD 100 128.5 Shr Et1/1 Altn BLK 100 128.6 Shr
SW2#sh spanning-tree int e0/0 detail Port 1 (Ethernet0/0) of VLAN0010 is designated forwarding Port path cost 100, Port priority 128, Port Identifier 128.1. Designated root has priority 4106, address aabb.cc00.0100 Designated bridge has priority 16394, address aabb.cc00.0200 Designated port id is 128.1, designated path cost 100 Timers: message age 0, forward delay 0, hold 0 Number of transitions to forwarding state: 1 Link type is shared by default BPDU: sent 57, received 0
SW2 had send BPDUs.
SW4#sh spanning-tree int e0/0 detail Port 1 (Ethernet0/0) of VLAN0010 is designated forwarding Port path cost 100, Port priority 128, Port Identifier 128.1. Designated root has priority 4106, address aabb.cc00.0100 Designated bridge has priority 8202, address aabb.cc00.0400 Designated port id is 128.1, designated path cost 200 Timers: message age 0, forward delay 0, hold 0 Number of transitions to forwarding state: 1 Link type is shared by default Bpdu filter is enabled BPDU: sent 0, received 0
However, SW4 has not received BPDUs because of BPDU filter.
This topology have L2 Loop VLAN 10. SW1#sh span vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 4106 Address aabb.cc00.0100 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 4106 (priority 4096 sys-id-ext 10) Address aabb.cc00.0100 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 100 128.1 Shr Et0/1 Desg FWD 100 128.2 Shr Et1/0 Desg FWD 100 128.5 Shr Et1/1 Desg FWD 100 128.6 Shr Et1/3 Desg FWD 100 128.8 Shr SW2#sh span vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 4106 Address aabb.cc00.0100 Cost 100 Port 5 (Ethernet1/0) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 16394 (priority 16384 sys-id-ext 10) Address aabb.cc00.0200 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 100 128.1 Shr Et1/0 Root FWD 100 128.5 Shr Et1/1 Altn BLK 100 128.6 Shr SW3#sh span vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 4106 Address aabb.cc00.0100 Cost 100 Port 1 (Ethernet0/0) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32778 (priority 32768 sys-id-ext 10) Address aabb.cc00.0300 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Et0/0 Root FWD 100 128.1 Shr Et0/1 Altn BLK 100 128.2 Shr Et1/0 Desg FWD 100 128.5 Shr Et1/1 Desg FWD 100 128.6 Shr SW4#sh span vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 4106 Address aabb.cc00.0100 Cost 200 Port 5 (Ethernet1/0) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 8202 (priority 8192 sys-id-ext 10) Address aabb.cc00.0400 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 100 128.1 Shr Et1/0 Root FWD 100 128.5 Shr Et1/1 Altn BLK 100 128.6 Shr EndFragment
