Frame+Relay

1) Introduction 1.1) Definition 1.2) History 2) Description of the implementation of Frame Relay 2.1) what does frame relay do?   2.2) why choose frame relay? 2.3) how does frame relay do?   2.4) how much does frame relay cost? 3) Issue regarding the frame relay 4) Conclusion 5) References
 * Table of content: **

According to the Internet Technology Handbook by CISCO, frame relay is defined as a high-performance wide area network (WAN) protocol that operates at the physical and data link layers of the OSI reference model. Basically, it is specially designed to provide a telecommunication service for cost-efficient data transmission for intermittent traffics between local area network (LANs) and between end-points in a WAN. Frame relay is one of the examples of packet-switched technology. Packet-switched networks allow end stations to share the network medium and the available bandwidth. The two techniques in packet-switching technology are variable-length packets and statistical multiplexing. Frame relay is described as a streamlined version of X.25. However, there is a difference between them; frame relay relays packets at physical layer and data link layer whereas X.25 provides services at network layer as well. Initially, frame relay was designed for use across Integrated Service Digital Network (ISDN) interfaces. Today it is used over in other network interfaces as well. The standardization of frame relay was begun to propose in the 1984. At that time, it was being proposed to the consultative committee on International Telephone and Telegraph (CCITT). However, the frame relay did not experience significant deployment during the late 1980s. This is due to the lack of interoperability and lack of completeness standardization. In 1990, Cisco, Digital Equipment Corporation (DEC), Northern Telecom and StarCom worked as a team to develop the frame relay technology. They developed a specification that conformed to the basic frame relay protocol that was being discussed in CCITT. The protocol was extended with features that provide additional capabilities for complex internetworking environments. The extensions are referred as Local Management Interface (LMI). Since the consortium’s specification was developed and published, many vendors have announced their support of this extended frame relay definition. American National Standards Institute (ANSI) and CCITT have subsequently standardized their own variations of the original LMI specification. These standardized specifications now are more commonly used than the original version. Now, frame relay is standardized by the International Telecommunications Union – Telecommunications Section (ITU-T) internationally. In the United States, frame relay follows the American National Standards Institute (ANSI) standard.
 * 1.0 Introduction **
 * 1.1 Definition: **
 * 1.2 History: **

Frame Relay is a public data packet switching service that supports data connectivity among geographically diverse locations. Frame Relay supports bursty data transmissions between local area networks (LANs) at speeds higher than the normal expected transmission rate. It uses fast packet technology to interconnect local area networks and other computers in geographically diverse locations. Frame Relay is widely used by end users to create a virtual private data network with at least two locations. Typically, end users are connecting mainframes, LANs, and WANs (wide area networks). The service is also used to connect to other networks and shared databases such as the Internet. In these types of configurations, an end user with only one location requires only one access circuit. Access speed is available at 56 Kbps, 384 Kbps, 1.544 Mbps, 6 Mbps, 22 Mbps and 45 Mbps. Frame Relay is a dedicated service. It is leased from a common carrier. Additionally, it is a switched service. Switched service is a circuit for which the endpoints may vary with each usage. The circuit is provided by a common carrier, which is routed through a switched network, providing circuit switching between public end users. There are two types of switched technology: circuit switched, and packet switched. In a switched circuit, a call is established only for as long as needed and then the session is disconnected. Frame Relay is a data network service used for LAN-to-LAN connections, remote access, and connecting to the Internet. Like DSL, it is used for carrying voice, data and video at fast rates. Users can download and upload large files quickly. Video conferencing can also be accomplished. Frame relay is well-suited for intra-corporate communications. It is also ideal for centralized applications, such as client/server or terminal-to-host. One of the features of Frame Relay are the network is managed and maintained by a service provider with Frame Relay service. Besides, there is less hardware required at each location than that used for private, dedicated networks. Fewer modems and multiplexers are needed to connect sites together. Another feature of Frame Relay is has a capacity that is more flexible than that of private lines. In the other hand, Frame Relay has its own internal backup routes so that customers do not have to provide multiple routes for reaching each location.
 * 2.0 Description of the implementation of Frame Relay **

Frame Relay sends information in packets called frames through a shared Frame-Relay network. Each frame contains all the information necessary to route it to the correct destination. So in effect, each endpoint can communicate with many destinations over one access link to the network. And instead of being allocated a fixed amount of bandwidth, Frame-Relay services offer a committed information rate (CIR) at which data is transmitted. But if traffic and the service agreement allow, data can burst above the committed rate.
 * 2.1 What does Frame Relay do? **

//** 2.2 Why choose Frame Relay? **// Since Frame Relay has a low overhead, it's a perfect fit for today's complex networks. There are several clear benefits of Frame Relay. First, multiple logical connections can be sent over a single physical connection, reducing the internetworking costs. By reducing the amount of processing required, performance and response time will be improve. And because Frame Relay uses a simple link layer protocol, the equipment usually requires only software changes or simple hardware modifications, so don't have to invest a lot of money to upgrade the system. Since Frame Relay is protocol independent, it can process traffic from different networking protocols like IP, IPX, and SNA. Frame Relay is an ideal choice for connecting Wide Area Networks (WANs) that have unpredictable, high-volume, and bursty traffic. Typically, these applications include data transfer, CAD/CAM, and client-server applications. Frame Relay also offers advantages for interconnecting WANs. In the past, setting up WANs required the use of private lines or circuit switching over a leased line. Single, dedicated lines are not needed to make each WAN-to-WAN connection with Frame Relay, reducing costs. Frame Relay Networks are ** broadly supported, well understood ****,** and ** easily put into operation ****.** Frame Relay is ** cheap ** and features a ** fast way of data transmission ** within and outside your computer networks. Frame Relay Service is robust and reliable. With Frame Relay we can get the most of our internet by running various internet-based applications. It's the best choice for companies with high networking requirements. Frame Relay is a digital packet network service that provides all the features and benefits of a dedicated network service without the expense of multiple dedicated circuits. A packet, or frame, is a chunk of data that is sent over the network. A switched network is a network where data is carried in the form of packets. This data is given an ID on a per packet basis and sent across the network in a very efficient way. In a Frame Relay network, circuits are connected to a packet switch within the network that ensures packets are routed to the correct location.
 * 2.3 ** **How does Frame Relay work?**

2.4 **How much does Frame Relay cost?** Frame Relay is a premium-leased line for exclusive use by the user. It is not billed on a distance-sensitive basis. It is a reasonably priced solution for data networks in which the traffic level changes from very low to very high in a short time-period. If the business sites are far apart, it is cost-effective. An even more cost effective solution is MPLS. It is also very useful and cost-effective for networks that require connections to multiple locations

In this topic, we would like to discuss about the issue Quality of service (QoS), and how it is related to frame relay. QoS is the ability to guarantee that an IP packet be sent from source to destination within a given time. In the other words, it refers to the capability of a network to provide a better service to selected network traffic over various technologies. The examples of technologies are frame relay, asynchronous transfer mode (ATM), Ethernet and 802.1 networks, Synchronous Optical NETwork (SONET) and IP-routed networks. The primary goal of QoS is to provide priority including dedicated bandwidth, control jitter, latency (required by some real-time and interactive) and improve loss characteristics. Without QoS, IP can be delayed or even lost as its concept is to provide a better service to certain flow. This can be done by either raising the priority of a flow or limiting the priority of another flow. Now, we would like to relate it with frame relay. Once the network has established a connection, the edge node of the frame relay network must monitor the traffic flow of the connections to ensure that the actual usage of network resources does not exceed this specification. The user’s information rate is being defined as some of the restrictions of frame relay. It allows the network to enforce the end user’s information rate and discard information when the subscribed access rate is exceeded. One of the functions of frame relay is the congestion notification and it is proposed as the congestion avoidance policy. If congestion happens, the user would not enjoy a good surfing experience. So, we would like to give an analogy to illustrate the situation. Let’s say an emergency vehicle (eg. ambulance, police car and so on), its siren is useless when the road is not full of vehicles; but if the road is “crowded”, the siren will be very helpful in making a way for it to move smoothly. Besides that, the emergency vehicle can choose to use the other routes if it knows the situation of the traffic earlier. Frame relay will always try to keep the network operating at its desired equilibrium point so that a certain QoS for the network can be met. Therefore, special congestion control bits have been incorporated into the address field of the frame relay. The special congestion control bits are Forward Explicit Congestion Notification bit (FECN) and Backward Explicit Congestion Notification Bit (BECN). FENC can inform the destination that congestion has occurred by setting its bit to 1. The bit number 1 indicates that congestion was experienced in the direction of the frame transmission. The same mechanism goes to BENC when it wants to inform the sender congestion has occurred.
 * 3.0 Issue regarding the frame relay: **

** 4.0 Conclusion ** Frame Relay is a technology that can create a robust wide area networking fabric that integrates information systems together to form an enterprise network. It is an affordable and capable service for supporting today's bandwidth intensive applications as well as those residing on legacy systems. Because logical connections are defined in software, it is easy to manage moves, changes, additions, and deletions of logical connections. Systems analysts should consider the use of Frame Relay for corporate applications that incorporate information systems at more than one location because of the technologies many technical, financial, and logistical advantages. Today, the biggest factors influencing the “useful” life expectancy of Frame Relay as a “live” production environment protocol are the massive increases in data transmission speeds that we are currently seeing in native IP-based networking. Much of these performance gains are in fact directly attributable to the improvements in transmission technologies such as fiber-optic cable and high-speed Ethernet over copper wire over longer distances (MANs & WANs). Frame Relay is still a useful technology, but it has competition. The technologies which are competing with Frame Relay or may evolve to displace Frame relay include Asynchronous Transfer Mode (ATM), Virtual Private Network (VPN), MultiProtocol Label Switching (MPLS). The future of frame relay is its interoperability with the next generation of high speed packetized data service - Asynchronous Transfer Mode (ATM). Many users prefer to connect their systems to ATM networks from frame relay networks rather than from native ATM networks (ATM equipment on location) because of the bandwidth constraints on low speed native ATM connections.

1) http://en.wikipedia.org/wiki/Frame_Relay 2) [|www.about.com] 3) [|www.wikianswer.com] 4) http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Frame-Relay.html 5) http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci212153,00.html 6) http://www.dcbnet.com/notes/framerly.html 7) http://www.protocols.com/pbook/frame.htm
 * 5.0 References **