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178 CCNP SWITCH 642-813 Official Certification Guide

c. So all hosts have the correct gateway
d. So the root bridge can have complete knowledge of the STP topology
2. Which of the following features protects a switch port from accepting superior BPDUs?
a. STP Loop Guard
b. STP BPDU Guard
c. STP Root Guard
d. UDLD
3. Which of the following commands can you use to enable STP Root Guard on a
switch port?
a. spanning-tree root guard
b. spanning-tree root-guard
c. spanning-tree guard root
d. spanning-tree rootguard enable
4. Where should the STP Root Guard feature be enabled on a switch?
a. All ports
b. Only ports where the root bridge should never appear
c. Only ports where the root bridge should be located
d. Only ports with PortFast enabled
5. Which of the following features protects a switch port from accepting BPDUs when
PortFast is enabled?
a. STP Loop Guard
b. STP BPDU Guard
c. STP Root Guard
d. UDLD
6. To maintain a loop-free STP topology, which one of the following should a switch up-
link be protected against?
a. A sudden loss of BPDUs
b. Too many BPDUs
c. The wrong version of BPDUs
d. BPDUs relayed from the root bridge
7. Which of the following commands can enable STP Loop Guard on a switch port?
a. spanning-tree loop guard
b. spanning-tree guard loop
c. spanning-tree loop-guard
d. spanning-tree loopguard enable

udld reset c. 11. UDLD d. The appearance of duplicate BPDUs d. Chapter 9: Protecting the Spanning Tree Protocol Topology 179 8. The appearance of two root bridges 9. Which of the following features effectively disables spanning-tree operation on a switch port? a. BPDU c. STP moves the link to the Blocking state. b. What must a switch do when it receives a UDLD message on a link? a. Send a UDLD acknowledgment c. STP Loop Guard detects which of the following conditions? a. STP BPDU Guard d. UDLD must detect a unidirectional link before which of the following? a. show udld errdisable . which one of the following commands should be used? a. STP 10. The sudden appearance of superior BPDUs b. STP moves the link to the Forwarding state. The sudden lack of BPDUs c. d. no udld d. STP BPDU filtering c. STP moves the link to the Listening state. Relay the message on to other switches b. Drop the message 12. STP Root Guard 13. POST b. clear errdisable udld b. Echo the message back across the link d. STP PortFast b. c. To reset switch ports that have been put into the errdisable mode by UDLD. The Max Age timer expires. Which of the following features can actively test for the loss of the receive side of a link between switches? a.