Refer to the exhibit. A network administrator is reviewing the configuration of switch S1. Which protocol has been implemented to group multiple physical ports into one logical link?
- DTP
- LACP
- PAgP
- STP
Answers Explanation & Hints: PAgP (Port Aggregation Protocol) is a Cisco proprietary protocol used to automatically bundle multiple physical links into a single logical link. PAgP has two modes of operation:
- Desirable: The port actively tries to negotiate a bundle with the other end of the link.
- Auto: The port passively waits to receive PAgP packets from the other end of the link.
In Auto mode, the port will respond to PAgP packets sent by the other end, but it won’t initiate PAgP negotiation on its own. If the other end is in Desirable mode, then the port will participate in PAgP negotiation and form a bundle.
So, in the given exhibit, the “channel-group 1 mode auto” command is configuring PAgP on interfaces Fa0/8 and Fa0/9, and the “interface Port-channel 1” command is configuring the logical port-channel interface with trunking and allowed VLANs. Therefore, PAgP is the protocol that has been implemented to group multiple physical ports into one logical link on this switch.