Based on the various performance metrics, the comparative study demonstrates that atm has less delay compared to the x. It was originally defined by the international telegraph and telephone consultative committee ccitt, now itut in a series of drafts and finalized in a publication known as the orange book in 1976 this makes it one of the oldest packetswitching communication protocols available. Frame relay provides the statistical multiplexing interface of x. All locations plug into the frame relay cloud, which is a conglomeration of dozens or hundreds of framerelay switches and routers.
Link layer provides for the reliable transfer of data across the physical link by transmitting the data as a sequence frames. Frame relay complete free download as powerpoint presentation. When frame relay detects an error, it simply drops the offending packet. Nov 02, 2005 frame relay is an industrystandard, switched data link layer protocol that handles multiple virtual circuits using highlevel data link control hdlc encapsulation between connected devices. Frame relay is essentially a packet switched network, and can be compared with an x.
Frame relay is a simplified form of packet switching, similar in principle to x. Basic concepts of frame relay explained in easy language. Lapb is a bit oriented protocol with frame structure as mentioned above. Also, the bandwidth used is allocated by the committed information rate cir value defined on the permanent virtual circuit pvc. C h a p t e r 15 frame relay frame relay is a layer 2 data link widearea networking wan protocol that operates at both layer 1 physical and layer 2 data link of the osi networking model. Studies have shown that frame relay based routers can process 10 times as many frames as routers relying on x. Presently, it is used for networks for atms and credit card verification. The basic frame protocol, which is used in the frame relay is hdlc and the typical speed is higher than the x. Introduced in the early 1980s and popular in europe up through the mid 1990s, x. Frame relay often is described as a streamlined version of x. Frame relay is a virtualcircuit widearea network that was designed in response to demands for a new type of wan in the late 1980s and early 1990s. Frame relay does not use storeandforward packet switching and hence has much less latency. The following figure illustrates a frame relay frame ansi t1.
This is possible because frame relay relies on digital transmission technology. Frame relay is a packetswitching telecommunication service designed for costefficient data transmission for intermittent traffic between local area networks lans and between endpoints in wide area networks wans. Frame relay frame relay is a highperformance wan protocol that operates at the physical and data link layers of the osi reference model. The structure of the frame relay frame shown in the figure. Thus, in general, framerelay is less expensive than dedicated wan lines, but customers are not guaranteed bandwidth. Customers have made significant investments in equipment and processes that depend on frame relay or x. C o n t e n t s widearea networking overview 1 finding feature information 1 frame relay 1 frame relay atm internetworking 4 switched multimegabit data service 4 link access procedure balanced and x. Frame relay is a scalable wide area network solution which makes use of packetmode transmission. The service, once widely available and implemented, is in the process of being discontinued by major internet service. At this layer, x25 provides data link control using lapb, which is subset of hdlc protocol.
Frame relay began as a strippeddown version of the x. Dlci spans 2 bytes ccna426 chapter 3 frame relay topologies a topology is the map or visual layout of the network. Defining frame relay frame relay is the advancement of x. All the slides are explained in a very simple manner.
View notes the advantages and limitations of using frame relay over x25 from ele 486 at princeton university. Comprehensive guide to configuring and troubleshooting frame. In the first layer physical another overhead is added, which includes the header and the trailer. The simulation results demonstrate that the atm has. Atm 2 a vc exists only while data is being transmitted on it, and all cells in a given atm. If large files transferred at high speeds, the priceperformance ratio is higher in x25. What are the advantages and limitations of using frame relay over x25. Asynchronous transfer mode atm is a cell relay protocol that, in combination with sonet, allows highspeed connections.
Dcn386 frame relay frame relay is developed by itu it is. Frame relay allows for a single serial interface on the router to connect multiple remote sites with the help of virtual circuits. The cloud is the frame providers network, and the customer has no control or even. The frames in frame relay contain an expanded link layer address field that enables frame relay nodes to direct frames to their destinations with minimal processing.
Besides, it can handle multiple data sessions on a single access line. Scribd is the worlds largest social reading and publishing site. Ppt frame relay powerpoint presentation free to download. The diagram below of an hdlc frame may be familiar, since without adding specific definitions of how the address, control and crc is used, the diagram is applicable to ibms sdlc, to x.
Note that the frame relay operates only on frames because the. It uses packet switching and virtual circuits, and provides a data rate up to 64kbps. It was originally designed for use in the 1970s and became very popular in 1980s. This page is sporadically maintained and incomplete.
Frame relay is often described as a streamlined version of x. In figure 33, spans frame relay network uses permanent virtual circuits pvc. In this section we discuss two endtoend wideareanetworking wan technologies, namely, x. X25 tutorial x25 protocol layer basics x25 frame tutorials. It begins at level 2 by testing for a valid frame and checking whether the frame contains user data or control information. Some of the important differences between a frame relay network and and x. View notes dcn386 frame relay from dcn 386 at seneca college. The screen shot below is an example of the displayed data. It is a newer form of packet switching designed for faster connections. The frame relay is the packet switched network as well as it may compare with the x. X25 and frame relay are examples of what type of wan. It includes a bibliography and a set of www sites with information on frame relay networks. The advantages and limitations of using frame relay over x25.
This layer defines the format of data packets and the. Although frame relay internetworking services were initially designed to operate over integrated. Expl wan chapter 3 frame relay house of technology. Some important characteristics of frame relay are, it allows bursty data. This is because frame relay typically operates over wan facilities that offer more reliable connection services and a. Frame relay connects a lan to a lan through a wan by allowing you to share the cost of bandwidth. Frame relay was originally planning to use lapd but lapd was complete and was missing certain features.
Most of todays popular lans, such as ethernet and token ring, are packetswitched networks. A pvc is the logical path along an originating frame relay link, through the network, and along a terminating frame relay link to its ultimate destination. It was originally defined by the international telegraph and telephone consultative committee ccitt, now itut in a series of drafts and finalized in a publication known as the orange book in 1976. Ccna4 25 chapter 3 frame relay encapsulation frame relay takes data packets from a network layer protocol and encapsulates them as the data portion of a frame relay frame. Frame relay introduction, features, working, history, format of frame relay. As we know packet switching system is a network of exchanges using high speed switches to connect multiple inputs with multiple outputs. In the older technology, the network delays, protocol overheads and equipment cost were the major drawbacks. Most of todays popular lans, such as ethernet and token ring, are packet switched networks. This service ensures a bitoriented, errorfree, and ordered delivery of frames. Examples of networks with virtual circuit capabilities include x. This tutorial explains how to configure frame relay step by step. Frame relay is strictly a layer 2 protocol suite, where as x. Frame relay is generally purchased as an alternative to a dedicated leased.
Note that the frame relay operates only on frames because the protocol includes no network layer functionality. Compare this to the physical path used by a dedicated connection. Frame relay is a new type of wan interface protocol of particular relevance to lan to lan interconnection applications. Frame relay computer network communications protocols. In many cases, frame relay is more efficient than x. In my posts, i use the term frame to represent a data link layer unit of information, and the term packet to represent a network layer unit of information. Data is sent in hdlc packets, referred to as frames. Even though several advanced technologies such as vpn, atm are available today, frame relay still rocks and will be in near future due to its features, benefits and lower cost in comparison with other point to point wan services. Pse dte are usually terminals dce devices are communication devices such as modems and packet switches and pse as generally located in carriers. Difference between frame relay and atm with comparison. It is based on x 25 and it can handle large bursts of data. Frame relay is one of the most popular wan service deployed over the past decade.