What mechanism does GLBP use to provide redundancy for gateways?

GLBP, or Gateway Load Balancing Protocol, employs a mechanism involving an Active Virtual Gateway (AVG) and Active Virtual Forwarders (AVFs) to ensure redundancy for gateways in a network.

In this protocol, the AVG is responsible for assigning MAC addresses to the AVFs while also managing and distributing the load among them. The AVFs are actual routers that handle traffic for the virtual IP address, which can lead to effective load balancing and redundancy. If the primary AVG fails, another router can take its place, maintaining the continuity of the gateway service. This redundancy is crucial for high availability, as it minimizes downtime and ensures seamless user access to network services.

Other mechanisms listed, such as upgrading the primary gateway or session persistence, do not directly pertain to how GLBP manages redundancy in gateway operations. Switching protocols likewise do not capture the essence of GLBP’s operation with respect to load balancing and redundancy among multiple gateways, focusing instead on different aspects of network communication. Hence, the role of AVG and AVFs distinctly defines how GLBP achieves its goals of redundancy and load distribution.