Explanation a port enabled with portfast will not

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Explanation: A port enabled with portfast will not send topology changes when a port goes up or down, but herewe see that 296 TCN’s were sent so we know that Gi 0/15 does not have portfast enabled. TCN’s are sent using BPDU’s over the root port, which we see is port channel 1. QUESTION NO: 75 DRAG DROP Answer: Explanation: Cisco 400-101 Exam "Pass Any Exam. Any Time." - 59
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QUESTION NO: 76 When you migrate a network from PVST+ to rapid-PVST+, which two features become inactive? (Choose two.) A. Root guard B. Loop guard C. UplinkFast D. UDLD E. BackboneFast F. Bridge Assurance Answer: C,E Explanation: It is good to know the UplinkFast and BackboneFast behavior before you start the migration process. Here, the Access1 switch runs Cisco IOS. This output is taken before migration to the rapid- PVST+ mode: Access1#show spanning-tree vlan 10 VLAN0010 Spanning tree enabled protocol ieee Root ID Priority 24586 Cisco 400-101 Exam "Pass Any Exam. Any Time." - 60
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Address 0015.63f6.b700 Cost 3019 Port 107 (FastEthernet3/0/1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 49162 (priority 49152 sys-id-ext 10) Address 000f.f794.3d00 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 Uplinkfast enabled Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Fa3/0/1 Root FWD 3019 128.107 P2p Fa3/0/2 Altn BLK 3019 128.108 P2p Access1#show spanning-tree summary Switch is in pvst mode Root bridge for: none Extended system ID is enabled Portfast Default is disabled PortFast BPDU Guard Default is enabled Portfast BPDU Filter Default is disabled Loopguard Default is disabled EtherChannel misconfig guard is enabled UplinkFast is enabled BackboneFast is enabled Configured Pathcost method used is short Name Blocking Listening Learning Forwarding STP Active ---------------------- -------- --------- -------- ---------- ---------- VLAN0010 1 0 0 1 2 VLAN0020 1 0 0 1 2 ---------------------- -------- --------- -------- ---------- ---------- 2 vlans 2 0 0 2 4 This output is taken after the mode is changed to rapid-PVST+: Access1#show spanning-tree vlan 10 Cisco 400-101 Exam "Pass Any Exam. Any Time." - 61
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VLAN0010 Spanning tree enabled protocol rstp Root ID Priority 24586 Address 0015.63f6.b700 Cost 3019 Port 107 (FastEthernet3/0/1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 49162 (priority 49152 sys-id-ext 10) Address 000f.f794.3d00 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 UplinkFast enabled but inactive in rapid-pvst mode Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Fa3/0/1 Root FWD 3019 128.107 P2p Fa3/0/2 Altn BLK 3019 128.108 P2p Access1#show spanning-tree summary Switch is in rapid-pvst mode Root bridge for: none Extended system ID is enabled Portfast Default is disabled PortFast BPDU Guard Default is enabled Portfast BPDU Filter Default is disabled Loopguard Default is disabled EtherChannel misconfig guard is enabled UplinkFast is enabled but inactive in rapid-pvst mode BackboneFast is enabled but inactive in rapid-pvst mode Configured Pathcost method used is short Name Blocking Listening Learning Forwarding STP Active ---------------------- -------- --------- -------- ---------- ---------- VLAN0010 1 0 0 1 2 VLAN0020 1 0 0 1 2 ---------------------- -------- --------- -------- ---------- ---------- 2 vlans 2 0 0 2 4 You can see in the show spanning-tree summary command output that UplinkFast and BackboneFast are enabled, but are inactive in rapid-PVST mode.
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