Which protocol helps manage and negotiate link bonding across switches?

Which protocol helps manage and negotiate link bonding across switches?

• A. Spanning Tree Protocol
• B. LACP (Link Aggregation Control Protocol)
• C. RADIUS
• D. DHCP

Answer: (B)

The concept here is how multiple physical links between switches can be combined into a single logical link to increase bandwidth and provide redundancy, with a protocol that handles the negotiation and maintenance of that bond. The protocol that does this is LACP, which is part of the IEEE standards for link aggregation. LACP dynamically negotiates which ports on each switch should join the same port channel, exchanges capability information, and keeps the group in sync so that traffic is distributed across the bonded links and the failure of any one link can trigger a reallocation of traffic. It can operate in active or passive modes and uses LACPDU frames to manage the aggregation, adding or removing links as needed to maintain an optimal, stable bond. Spanning Tree Protocol, while important for preventing loops, does not create or manage bonded links. RADIUS handles authentication and authorization, and DHCP assigns IP addresses—functions unrelated to link bonding.

The concept here is how multiple physical links between switches can be combined into a single logical link to increase bandwidth and provide redundancy, with a protocol that handles the negotiation and maintenance of that bond. The protocol that does this is LACP, which is part of the IEEE standards for link aggregation. LACP dynamically negotiates which ports on each switch should join the same port channel, exchanges capability information, and keeps the group in sync so that traffic is distributed across the bonded links and the failure of any one link can trigger a reallocation of traffic. It can operate in active or passive modes and uses LACPDU frames to manage the aggregation, adding or removing links as needed to maintain an optimal, stable bond. Spanning Tree Protocol, while important for preventing loops, does not create or manage bonded links. RADIUS handles authentication and authorization, and DHCP assigns IP addresses—functions unrelated to link bonding.