Cisco Certified Network Associate (CCNA) Practice Exam

What is the Cisco proprietary etherchannel protocol?

1. Link Aggregation Control Protocol (LACP)

2. Port Aggregation Control Protocol (PAgP)

3. Rapid Spanning Tree Protocol (RSTP)

4. Ethernet Channel Grouping Protocol (ECGP)

The correct answer is: Port Aggregation Control Protocol (PAgP)

The correct answer is Port Aggregation Control Protocol (PAgP). PAgP is a Cisco proprietary protocol used to automatically create an EtherChannel, which allows multiple physical Ethernet connections to aggregate and function as a single logical link. This aggregation provides increased bandwidth and redundancy. PAgP helps in the negotiation and establishment of EtherChannels between Cisco switches. It detects and maintains an EtherChannel by exchanging packets that carry information about the ports and their configurations. When these ports are configured correctly, PAgP can dynamically form the EtherChannel without manual intervention, which simplifies network management. Understanding the function of PAgP is crucial for network engineers working with Cisco equipment, as it ensures efficient use of bandwidth and enhances the resiliency of connections in a network environment. The other protocols mentioned either do not pertain to EtherChannel or are not Cisco-specific.