Refer to the exhibit.
Which EtherChannel negotiation protocol is configured on the interface f0/13 f0/15?
A. Link Combination Control Protocol
B. Port Aggregation Protocol
C. Port Combination Protocol
D. Link Aggregation Control Protocol
Suggested Answer: Explanation
PAgP modes are off, auto, desirable, and on. Only the combinations auto-desirable, desirable- desirable, and on-on will allow a channel to be formed. .
1. on: PAgP will not run. The channel is forced to come up.
2. off: PAgP will not run. The channel is forced to remain down.
3. auto: PAgP is running passively. The formation of a channel is desired; however, it is not initiated.
4. desirable: PAgP is running actively. The formation of a channel is desired and ini- tiated.
The Link Aggregate Control Protocol (LACP) trunking supports four modes of operation:
On: The link aggregation is forced to be formed without any LACP negotiation .In other words, the switch neither sends the LACP packet nor processes any
<img src="https://www.examtopics.com/assets/media/exam-media/01585/n18886300005.png" alt="Reference Image" />
inbound LACP packet. This is similar to the on state for PAgP.
Off: The link aggregation is not formed. We do not send or understand the LACP packet.
<img src="https://www.examtopics.com/assets/media/exam-media/01585/n18886300002.png" alt="Reference Image" />
This is similar to the off state for PAgP.
<img src="https://www.examtopics.com/assets/media/exam-media/01585/n18886300004.png" alt="Reference Image" />
Passive: The switch does not initiate the channel but does understand inbound LACP packets. The peer (in active state) initiates negotiation (when it sends out
<img src="https://www.examtopics.com/assets/media/exam-media/01585/n18886300001.png" alt="Reference Image" />
an LACP packet) which we receive and answer, eventually to form the aggregation channel with the peer. This is similar to the auto mode in PAgP.
Active: We can form an aggregate link and initiate the negotiation. The link aggregate is formed if the other end runs in LACP active or passive mode. This is
<img src="https://www.examtopics.com/assets/media/exam-media/01585/n18886300003.png" alt="Reference Image" />
similar to the desir- able mode of PAgP.
In this example, we see that fa 0/13, fa0/14, and fa0/15 are all in Port Channel 12, which is operating in desirable mode, which is only a PAgP mode.
This question is in 300-115 Implementing Cisco IP Switched Networks (SWITCH) Exam
For getting Cisco Certified Network Professional (CCNP) Routing and Switching Certificate
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