Abstract

This paper will give an overview of a medium-sized business that will need to consider WAN technology using Frame relay technology within the company for the future expansion to other towns and cities. The Frame relay analysis will include the operation of frame relay, what equipment is needed, what switching technologies are employed by frame relay and how frame relay is actually brought into the business premises. Frame Relay in a WAN

Frame Relay Frame Relay is one of the most common WAN protocols. This high performance protocol operates at the Physical and Data Link layers of the OSI, performing any type of serial interface. This technology was developed at an attempt to resolve some of the communication problems that the other protocols would not. There was an increased need for higher speeds, an increased need for larger bandwidth efficiency, an increase in intelligent network devices that lower protocol processing, and the need to connect LANs and WANs. The Frame relay evolved passed the X.25 as a less careful, but less burdensome protocol designed to transmit packets across a network. (Horton, 2010) Frame relay is known all around the world in many different networks. There are many terms that describe and refer to Frame relay and Wide Area Networking in telecommunications. These terms are also noted when referring to Local Area Networking as well. The table below describes these terms. (Horton, 2010)
Table 1 – Frame Relay Terms
CIR Committed Information Rate – the minimum level of throughput as guaranteed by the service provider.
DCE Data Circuit-terminating Equipment – a device on the service provider's network that connects to the customer's DTE.
DTE Data Terminal Equipment – a device at the customer's site that connects to the service provider's DCE.
DLCI Data Link Connection Identifier – a 10-bit number used to uniquely identify a virtual circuit end-point on the customer's Frame Relay network.
HDLC High-level Data Link Control – a layer-2 protocol used to control data flow and provide error detection.
LMI Line Management Interface – a protocol that provides line status and other management information to the end user of a Frame Relay connection.
PPP Point-to-Point Protocol – an alternative to HDLC.
PVC Permanent Virtual Circuit – a connection between two nodes on a Frame
Relay cloud that allows the exchange of data.

Needed Equipment For each business, the needed and or desired equipment for Frame relay can differ based on expense, availability, and the business need of the network. Routers with separate CSU/DSUs (Channel Service Unit/ Data Service Unit) or routers with the CSU/DSUs built in are usually used in networks that are located at the customer’s location of their digital connection. But using Frame Relay, it connects to the Frame Relay switch known as the Frame Relay access device (FRAD). The FRAD is also called the Frame Relay assembler/disassembler. Usually the local connection is handled by the network administrator until it enters the public data network (PDN). The ITU-T and ANSI describes the Frame Relay as a connection between the DTE (Data Terminating Equipment) and the DCE (Data Communications Equipment). The telecommunications company supplies the DCE, the switching equipment, which is the connection to the public data network. The DTE equipment belongs to and is maintained by the customer and is known as the customer premise equipment. These items that are included in the PDN, such as the Frame Relay switch, are the responsibility of the telecommunications provider and not the customer’s. This is one reason that the Frame Relay can be used over many different network interfaces. (netcert.tripod.com) Orbit-Computer Solutions provides a figure where you can see the data that moves between the DTEs and DCEs as shown below.

Switching Technologies Frame Relay uses a packet-switched technology where end stations are enabled to dynamically share the bandwidth that’s available and the network medium. These packets are then switched between the various network sections until the destination is reached. In a packet-switched network, statistical multiplexing methods are used to control network access. This is a benefit because these methods will accommodate to offer more flexibility and efficiency of the bandwidth. (netcert.tripod.com)
Frame Relay is often considered the streamlined version of the X.25, a conservative design that numbers, acknowledges, and supervises every packet that even asks network switches to retransmit packets that don’t make the trip across the network. Frame Relay is strictly a Layer 2 protocol group, where X.25 delivers services to Layer 3. (netcert.tripod.com)

Advantages and Disadvantages In deciding where or not using Frame relay in setting up a wide area network, the business would need to consider the requirements of their network and the capabilities of the frame relay. In reviewing the advantages of Frame relay, we find that cost is the main advantage. Frame relay has the capability to provide the same services at a significantly lower cost because the customer is only required to make a dedicated point-to-point connection to the provider’s nearest switch, then the data will travel over the provider’s shared network. Since the price of usage on these lines increase with distance, the short distance options would be the right option when transmitting over a longer distance. (Horton, 2010) Also, since there is also no error detection feature in Frame Relay, this allows for faster processing, and lower overhead costs than the X.25. Frame Relay is also protocol independent where it accepts data from many other different protocols. Data is then encapsulated by the equipment from the Frame relay, not the network. Another advantage is that Frame relay is completely digital; this reduces the chance of errors and the increases the transmission rates; which usually operate at 56 kbps to 1.544 Mbps. (CPCS Technologies,) Determining whether or not frame relay would necessarily be the best choice for a WAN technology in all circumstances, the two disadvantages we need to review are the slowdowns caused from the congestion on the network and the possible difficulty ensuring the quality of service (QoS) being provided. Since all of the customers use a common network, there are down times when data transmission exceeds network capacity and there are congestion times. There are other options beside Frame Relay. X.25 is an option a well a ATM. Although X.25 is an option, it is not recommended because X.25 is used over analog which not always available.

Conclusion Frame Relay can provide many benefits when maintained and designed correctly. It is a very convenient and cost-effective WAN solution for use around the country. Frame Relay also makes the possibility for growth and expansion more favorable because of the flexibility of WANs. It is an easy setup for any system administrator and an easy transition for the business. As shown below, this is the typical Frame Relay Network provided by CPCS Technologies. References

Orbit-Computer Solutions.Com, Computer Training & CCNA Networking Solutions.
(2011, June), Frame Relay – WAN Connection. Retrieved September 25, 2012, from http://www.orbit-computer-solutions.com/Frame-Relay-(WAN-Connection).php

Horton, David (2010), WAN Design with Frame Relay. Retrieved September 25, 2012, from http://www.happy-monkey.net/papers/frame-relay-paper.pdf CPCS Technologies, Defense and Public Safety Technology Consulting Service. Frame Relay Overview. Retrieved September 25, 2012, from http://www.cpcstech.com/frame-relay-information.htm