Table of Contents
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Chapter 16
Configuring Frame Relay
Frame Relay Overview
Frame Relay Overview on page 379
Configuring Frame Relay Interface Encapsulation on page 380
Configuring Frame Relay Control Bit Translation on page 383
Configuring the Media MTU on Frame Relay Interfaces on page 384
Setting the Protocol MTU with Frame Relay Encapsulation on page 385
Configuring Frame Relay Keepalives on page 385
Configuring Inverse Frame Relay ARP on page 387
Configuring the Router as a DCE with Frame Relay Encapsulation on page 388
Configuring Frame Relay DLCIs on page 388
The Frame Relay protocol allows network designers to reduce costs by using shared
facilities that are managed by a Frame Relay service provider. Users pay fixed charges
for the local connections from each site in the Frame Relay network to the first point
of presence (POP) in which the provider maintains a Frame Relay switch. The portion
of the network between the endpoint switches is shared by all the customers of the
service provider, and individual data-link connection identifiers (DLCIs) are assigned
to ensure each customer receives only their own traffic.
Users contract with their providers for a specific minimum portion of the shared
bandwidth Committed Information Rate (CIR) and for a maximum allowable peak
rate, Burst Information Rate (BIR). Depending on the terms of the contract, traffic
exceeding the CIR can be marked as eligible for discard, in the event of network
congestion, or a best effort term can apply up to the BIR rate.
Frame Relay does not require private and permanently connected wide area network
facilities, unlike some older WAN protocols.
Frame Relay was developed as a replacement for the older and much slower X.25
protocol. It scales to much higher data rates because it does not require explicit
acknowledgment of each frame of data.
You can configure the Frame Relay protocol on SONET/SDH, E1/E3, and T1/T3
physical router interfaces, and on the channelized DS3, channelized OC12,
channelized T3 intelligent queuing (IQ), channelized OC12 IQ, and channelized E1
IQ interfaces.
379
Frame Relay Overview
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