Which two protocol choices do you have when you are implementing an EtherChannel bundle? (Choose two.)
- LAPD
- PAgP
- LACP
- PADP
- dot1Q
Explanation: EtherChannel can be established using two main negotiation protocols that allow switches to automatically form a bundle by exchanging control packets:
- LACP (Link Aggregation Control Protocol): This is part of an IEEE specification (802.3ad). Because it is a standard, it is used to facilitate EtherChannels in mixed-vendor environments. It ensures configuration consistency regarding speed, duplex settings, and VLAN information before bundling ports.
- PAgP (Port Aggregation Protocol): This is a Cisco proprietary protocol, meaning it only works on Cisco devices. It provides negotiation benefits similar to LACP by identifying neighbors and comparing port capabilities to ensure they match before forming the logical link.
While a third option exists—Static persistence (the "on" mode)—it is a manual configuration that does not use a negotiation protocol to exchange control packets. Other options provided, such as dot1Q, refer to IEEE 802.1Q, which is a protocol used for VLAN trunking and tagging rather than link aggregation.
Related exam: Modules 1 – 7: Checkpoint Exam: Network Switching Answers (CCNP ENCOR v9)
