Which protocol is used to aggregate multiple physical links into a single logical link to increase bandwidth and provide redundancy?

Which protocol is used to aggregate multiple physical links into a single logical link to increase bandwidth and provide redundancy?

• A. DHCP
• B. STP
• C. LACP
• D. DNS

Answer: (C)

Pooling multiple physical links into one logical channel increases total bandwidth and adds redundancy. The protocol that handles this negotiation and management is LACP (Link Aggregation Control Protocol). LACP groups several Ethernet ports into a single port-channel or LAG, allowing a switch to treat them as a single interface. Through special control messages (LACP data units), both ends agree which ports participate, share a common system identifier, and decide how traffic is distributed across the member links. If one link fails, the remaining links continue to carry traffic, preserving connectivity and improving resilience. Traffic is balanced across the links using a hashing algorithm, which helps maximize overall throughput. For LACP to work, both ends must be configured to support it; if one side is not configured or is set to passive while the other is active, aggregation won’t form. DHCP assigns IP addresses, DNS resolves domain names, and STP prevents loops by choosing stable paths—these functions are not about bonding links.

Pooling multiple physical links into one logical channel increases total bandwidth and adds redundancy. The protocol that handles this negotiation and management is LACP (Link Aggregation Control Protocol). LACP groups several Ethernet ports into a single port-channel or LAG, allowing a switch to treat them as a single interface. Through special control messages (LACP data units), both ends agree which ports participate, share a common system identifier, and decide how traffic is distributed across the member links. If one link fails, the remaining links continue to carry traffic, preserving connectivity and improving resilience. Traffic is balanced across the links using a hashing algorithm, which helps maximize overall throughput. For LACP to work, both ends must be configured to support it; if one side is not configured or is set to passive while the other is active, aggregation won’t form. DHCP assigns IP addresses, DNS resolves domain names, and STP prevents loops by choosing stable paths—these functions are not about bonding links.