Specifications

64 IBM Voice Over Frame Relay Perform Guide

4.1.2 Fully Meshed and Partially Meshed

Figure 32. Fully Meshed and Partially Meshed

There are two common topologies for frame relay networks:

1. Fully meshed: each endpoint has a direct virtual link to every other endpoint,

via one physical connection. This is often an expensive solution, since each

router needs a DLCI per endpoint router. So in the above example, each router

needs three DLCIs to get to each of the remote sites.

2. Partially meshed: In this scenario, there is a hub router which has connections

to all of the remote sites but the remote sites (spokes) have a single

connection.

4.1.3 Local Management Interface (LMI)

FR PVCs can be configured on an interface or learned via LMI. Some protocols

require you to configure the DLCI on the interface. LMI is a local management

interface and it is used to determine the status of PVCs on a FR interface. If LMI

is enabled, the FR interface is active when a successful exchange of LMI frames

occurs between the router and the FR switch; however, no data can be received

from or transmitted to another router until an LMI status message indicates that

the PVC status for the DLCI to the other router is active.

Fully Meshed

Partially Meshed