Cisco Certified Network Associate (CCNA) Practice Exam

Which protocol is one of the two common standards for EtherChannels that is considered an open standard?

1. Cisco's Port Aggregation Protocol (PAGP)

2. EtherChannel Protocol (ECP)

3. IEEE Link Aggregation Protocol (LACP)

4. Rapid Spanning Tree Protocol (RSTP)

The correct answer is: IEEE Link Aggregation Protocol (LACP)

The correct choice is indeed the IEEE Link Aggregation Protocol (LACP). This protocol is part of the IEEE 802.3ad standard and is widely recognized as an open standard for link aggregation. LACP enables the bundling of multiple Ethernet links into a single logical link, which allows for increased bandwidth and provides redundancy in the network. Unlike proprietary protocols, such as Cisco's Port Aggregation Protocol (PAGP), LACP is implemented across various vendor devices, making it a versatile option for multi-vendor environments. The use of LACP helps ensure interoperability between different hardware and software components while supporting load balancing and fault tolerance. Other options, while related to networking, do not apply in the same context. For instance, Cisco’s Port Aggregation Protocol is proprietary to Cisco and does not promote inter-device compatibility across different vendors. EtherChannel Protocol is not a standardized protocol recognized in current networking practices, and Rapid Spanning Tree Protocol, although important for preventing loops in a network, does not pertain to link aggregation. Thus, LACP is the optimal choice for an open standard in this scenario.