Avaya P332G-ML manual Layer 3 Features, Modes of Operation, Forwarding, Redundancy

Chapter 1 Overview

Layer 3 Features

Modes of Operation

The P332G-ML has two modes of operation (in each mode, Layer 2 is always active):

•Layer 2-only mode

•Router mode and Layer 2.

Note: This section is only applicable if you either purchased a preconfigured P332G-ML or purchased a Routing License Key Certificate and activated the License Key.

Forwarding

The P332G-ML forwards IP packets between IP networks. When it receives an IP packet through one of its interfaces, it forwards the packet through one of its interfaces. P332G-ML supports multinetting, enabling it to forward packets between IP subnets on the same VLAN as well as between different VLANs. Forwarding is performed through standard means in Router mode.

Redundancy

Routing protocols naturally provide some level of redundancy. However, IP stations that are manually configured with a single ‘default gateway’ IP address do not naturally recover when their default gateway fails. These stations do not automatically try to use other routers or Layer-3-switches connected to the same subnet.

The P332G-ML supports two router redundancy protocols, VRRP and SRRP, to solve this problem.

Virtual Router Redundancy Protocol (VRRP)

VRRP is an IETF protocol designed to support redundancy of routers on the LAN, as well as load balancing of traffic. VRRP is transparent to host stations, making it an ideal choice when redundancy, load balancing and ease of configuration are all required.

The concept underlying VRRP is that a router can backup other routers, in addition to performing its primary routing functions. This redundancy is achieved by introducing the concept of a virtual router. A virtual router is a routing entity associated with multiple physical routers. The routing functions of the virtual router are performed by one of the physical routers with which it is associated. This router is known as the master router.

For each virtual router, VRRP selects a master router. If the selected master router fails, another router is selected as master router.

P332G-ML User’s Guide 7