Which of the following best describes Arista’s MLAG feature?

Arista's Multi-Chassis Link Aggregation (MLAG) allows two physical switches to appear as a single logical switch to a connected device. This enables the creation of a standard Link Aggregation Group (LAG) with member ports spread across the two MLAG peer switches. The primary benefit of this architecture is that both uplinks in the LAG can be active and forward traffic simultaneously. This active-active forwarding model eliminates the need for Spanning Tree Protocol (STP) to block one of the redundant links to prevent loops, thereby utilizing the available uplink bandwidth much more efficiently and providing superior resiliency.

B. combines up to seven switches in a ring topology

This is incorrect. MLAG creates a domain between a pair of two switches, not seven. Ring topologies are associated with other protocols, not the core function of MLAG.

C. negotiates speed and duplex settings on 10Gb interfaces

This describes autonegotiation, a fundamental Ethernet feature. While MLAG operates over Ethernet, its purpose is not to negotiate physical link parameters.

D. saves all dropped packets to be used at a later time

This describes a function that does not exist in standard networking. Dropped packets are discarded, not stored for later use. This is unrelated to MLAG.

1. Arista Networks, EOS 4.31.1F - MLAG Configuration Guide: In the "MLAG Basics" section, it states, "MLAG allows a client to form a Port-Channel to two upstream switches for physical diversity and increased bandwidth." Under the "MLAG and Spanning Tree Protocol (STP)" section, it clarifies, "MLAG replaces Spanning Tree Protocol (STP) at the aggregation layer of the network, using all links to forward traffic." This directly supports the concept of utilizing bandwidth more efficiently by avoiding STP blocks.

2. Arista Networks, Design and Deployment Guides - L2 MLAG - Recommended Configuration (2023): Section 1.2, "Benefits of MLAG," states: "All links in an MLAG are used for forwarding traffic. Spanning-tree can be eliminated from the access to aggregation layer of the network where MLAG is deployed, allowing for faster convergence times." This confirms that MLAG avoids STP blocking to use all available bandwidth.