READ Free Dumps For Cisco- 400-101
| Question ID 18606 | When you migrate a network from PVST+ to rapid-PVST+, which two features become
inactive? (Choose two.)
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| Option A | Root guard
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| Option B | Loop guard
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| Option C | UplinkFast
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| Option D | UDLD
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| Option E | BackboneFast
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| Option F | Bridge Assurance
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| Correct Answer | C,E |
Explanation 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 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 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 ---------------- ---- --- --------- -------- --------------------
| Question ID 18607 | In a network where a Layer 2 switch interconnects several routers, which feature restricts
multicast packets for each IP multicast group to only those mulicast router ports that have
downstream receivers joined to that group?
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| Option A | PIM snooping
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| Option B | IGMP snooping
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| Option C | IGMP filter
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| Option D | IGMP proxy
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| Correct Answer | A |
Explanation Explanation: In networks where a Layer 2 switch interconnects several routers, such as an Internet exchange point (IXP), the switch floods IP multicast packets on all multicast router ports by default, even if there are no multicast receivers downstream. With PIM snooping enabled, the switch restricts multicast packets for each IP multicast group to only those multicast router ports that have downstream receivers joined to that group. When you enable PIM snooping, the switch learns which multicast router ports need to receive the multicast traffic within a specific VLAN by listening to the PIM hello messages, PIM join and prune messages, and bidirectional PIM designated forwarder-election messages. Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12- 2SX/configuration/guide/book/snooppim.html