CCIE R&S Written Overview: Frame Relay

Frame Relay Overview

• Non-Broadcast Multi Access (NBMA)

– Address resolution issues implied

• Data Link Connection Identifier (DLCI)

– Layer 2 addressing

– DLCI number only locally significant

• Local Management Interface (LMI)

– DTE / DCE (router / switch) communication

– Reports virtual circuit (VC) status

Frame Relay LMI

• Enabled automatically with Frame Relay

– encapsulation frame-relay

• LMI Types

– Automatically detected

– frame-relay lmi-type [cisco | ansi |q933a]
– show frame-relay lmi

• LMI Advertises VC Status

– show frame-relay pvc

• Status can be…

– Active

– Inactive

– Deleted

– Static

Full Mesh

• Topology where all devices have a direct layer 2 circuit to each other

• More closely emulates a LAN

• More expensive to provision