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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

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