What is Frame Relay? How to Configure Frame Relay Router Example

By | 9th November 2015

Configuring Frame Relay on Cisco a Router.

The figure below shows the basic Frame Relay configuration on a Cisco router, connected directly to a dedicated Frame Relay switch, or DCE.

All router interface had been configured with IP addresses and routing protocol – RIPv2.

frame relay config


R1#config t

R1(config)#interface serial 0/0/0

R1(config-if)#encapsulation frame-relay

R1(config-if)#frame-relay lmi-type ansi

R1(config-if)#frame-relay map ip 102 broadcast

R1(config-if)#no shutdown


R2#config t

R2(config)#interface serial 0/0/1

R2(config-if)#encapsulation frame-relay

R2(config-if)#frame-relay lmi-type ansi

R2(config-if)#frame-relay map ip 201 broadcast

R(config-if)#no shutdown

How To Configure Frame Relay with Subinterfaces

In the topology above, the frame from R1 use DLCI value 102. It leaves the router (R1) using VC 102. This process of VC-port mapping continues through the WAN until the frame reaches its destination at (R2 with value) DLCI 201, From R2, the frame use DLCI value 201 to identify its network VC to R1.The DLCI is stored in the address field of every frame transmitted.

The LMI( Local Management Identifier) acts like a keepalive mechanism that provides status information about Frame Relay connections between the router (DTE) and the Frame Relay switch (DCE).

The Broadcast Keyword is used because Frame Relay, ATM, and X.25 are non-broadcast multiple access (NBMA) networks, Because NBMA does not support broadcast traffic, using the broadcast keyword is a way to forward routing updates by RIP, EIGRP and OSPF.

Data Link Connection Identifier (DLCI)

Virtual  Circuits (VC)

Link Management Identifier (LMI)

How to Configure Frame Relay

How to Troubleshoot Frame Relay

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