Understanding Link Aggregation

C

The IEEE 802.3ad link aggregation specification enables multiple Ethernet interfaces to be grouped together and form a single link layer interface, also known as a link aggregation group (LAG) or bundle. The physical links participating in a LAG are known as member links. LAGs are commonly used to aggregate trunk links between access and aggregation switches.

Answer:

The correct answer is D. Link aggregation combines multiple Ethernet interfaces into a multilink-layer interface.

Explanation:

Link aggregation is a technique that combines multiple physical Ethernet links into a single logical link. This can provide increased bandwidth, improved fault tolerance, and load balancing. In link aggregation, multiple Ethernet links are combined into a single logical link using a link aggregation protocol (LACP) or static link aggregation.

Option A is incorrect because link aggregation does not provide control plane redundancy. It provides data plane redundancy by combining multiple physical links into a single logical link. Control plane redundancy is provided by other protocols such as VRRP or HSRP.

Option B is also incorrect because link aggregation does not provide an active-passive failover mechanism for redundant Layer 2 links. Instead, link aggregation provides a mechanism for load balancing traffic across multiple links, which can improve overall network performance.

Option C is partially correct but incomplete. Link aggregation combines multiple Ethernet interfaces into a single link-layer interface that appears as a single Ethernet link to higher-layer protocols. However, the link-layer interface created by link aggregation is actually a multilink-layer interface because it combines multiple physical Ethernet links into a single logical link.

Therefore, option D is the correct answer as it correctly describes link aggregation as a technique to combine multiple Ethernet interfaces into a multilink-layer interface.