30-04-2012, 03:04 PM
WAN Design with Frame Relay
frame-relay-paper.pdf (Size: 395.6 KB / Downloads: 84)
Frame Relay in a Nutshell
Frame Relay is a layer-2 protocol used in wide area networking. It uses the
telecommunications provider's packet-switching infrastructure to move data. Frame
Relay can provide speeds from 56kbps DS0 up to 43Mbps DS3 connections depending
on the capability of the service provider's network.
Terminology
There are many terms used to describe Frame Relay, and Wide Area Networking (WAN)
in general, that may be foreign to those who are familiar only with Local Area Network
design. Some of the more common Frame Relay terms are briefly described below.
A Sample Design
To solidify a basic understanding of Frame Relay consider the example of a fictional
company called Zippy's Chips. Zippy's is a nationwide company that makes potato chips
and corn chips for sale in vending machines across the country. They have supply offices
in Boise, Idaho and Des Moines, Iowa as well as manufacturing centers in Dallas, Texas;
Portland, Oregon and Chicago, Illinois. The Zippy's corporate office is located in
Schaumburg, Illinois. Distribution of Zippy's products is handled by its business partner,
Vend-O-Land Systems, headquartered in St. Louis, Missouri.
Deciding if Frame Relay is Right for the Network
In order to make an informed decision about wide area connectivity Zippy's has to know
the requirements of their network as well as the capabilities of FDP's Frame Relay
service.
Disadvantages of Frame Relay
The two main disadvantages of Frame Relay are slow downs due to network congestion
and difficulty ensuring Quality of Service (QoS). Because all of a provider's Frame Relay
customers use a common network there can be times when data transmission exceeds
network capacity. The difficulty ensuring QoS is due to the fact that Frame Relay uses
variable-length packets. It is easier to guarantee QoS when using a fixed-length packet.
Zippy's needs to decide how significant these disadvantages are to the needs of their
network and how to mitigate against them.
Conclusion
When designed correctly Frame Relay can provide a cost-effective WAN solution for
businesses with offices dispersed across the country. The example of Zippy's Chips
shows how Frame Relay can be used to provide connectivity to multiple sites as well as
redundancy to aid in disaster recovery. The choice of Frame Relay also allows for easy
expansion of the business and flexibility in the design of the network.