Previous Table of Contents Next


Frame Relay Internetwork Service Testing

The most important reason to test the internetwork service is the increasing number of premium services being offered. These premium services, such as the end-to-end management of network services, rely on LAN/WAN analysis at the higher-level functions that only internetwork testing can verify.

Internetwork service testing begins with the Frame relay devices themselves. These devices generate and receive the Frame relay frames. Simultaneous monitoring of both sides of these devices can be done to verify that LAN traffic to the router is correctly forwarded and encapsulated in Frame relay. This verification of connectivity across the router also ensures correct configuration. The user should test all routers before installation on the network and before calling the provider’s wide area support group when switch problems occur.

The Echo Test. Another internetwork device test that can be performed to verify connectivity across the network is the echo test. The echo test’s key applications are for implementation and installation of routers when establishing connectivity, for in-service measurements on in-service and out-of-service equipment, and for performing round-trip delay measurements through the network.

The echo test eliminates the need to take down the service when testing network connectivity. In an echo test, the test equipment bounces (pings) a packet across the network to the far-end router (or host) and awaits a response. It checks the connections through the WAN by monitoring both the outgoing ping packet and the returning response from the remote host.

Simultaneous Monitoring of the WAN and LAN. Simultaneous monitoring of the WAN and LAN should also be performed. By looking at encapsulated LAN protocols, users can verify that customer traffic is correctly addressed, encapsulated, and transmitted over the WAN. In the opposite direction, users should track packets to ensure that Frame relay information is removed and that they are correctly routed to their destination on the LAN.

Multiport analysis provides the ability to test an internetwork at various access points simultaneously. For example, users could access LAN segments. Once the link is established, users can stress the circuit using a traffic generator.

Commissioning the Frame Relay Service

Once the testing of the Frame relay devices and network is complete, users can concentrate on commissioning the Frame relay service. This application focuses on emulating the DCE and DTE by generating Frame relay packets to see how the network reacts to these packets.

First, the test should provide for Annex D ANSI signaling protocol LMI emulation to imitate network conditions. This action ensures that the network can process the frames across the LAN and the WAN. Once this is accomplished, the user can monitor layer-two and LMI signaling statistics. The test equipment should then stress test the line by generating frames to ensure that the network stands up to agreed communication rates. The commissioning process verifies and sectionalizes inside and outside the Frame relay cloud.

End-to-End Analysis

Finally, users want to take advantage of the verification of end-to-end LAN/WAN connectivity. End-to-end analysis ensures the integrity of the entire internetwork. With this application, users can generate traffic to remote LANs to verify connectivity or capacity handling. In addition, users can monitor both local and remote trends in network operation to plan for network changes and expansion.

TRAINING ISSUES UNIQUE TO FRAME RELAY

One aspect that is often overlooked in technical articles, books, and magazines is the training of personnel in technology, network applications, and troubleshooting methodology. Yet training is extremely important when implementing a new technology such as frame relay.

THE PROVIDER’S PERSPECTIVE

From the service provider’s perspective, training is critical in overcoming a technician’s lack of protocol or packet-switching knowledge. These technicians, who must install the Frame relay equipment and services, may know how to install DDS or T1 links, but they may have limited protocol experience and most likely have never been exposed to Frame relay. Frame relay training provides the technology background these technicians need. It also provides the installation and troubleshooting background they need to maintain the service.

Training can point out to the technician the prospective problems that occur when testing Frame relay and how to solve them. For example, the physical layer may work but the service may not. This is often caused by switch configuration problems, such as the switch not being configured, being configured incorrectly, or the provider and subscriber configuring their switches incompatibly.

THE SUBSCRIBER’S PERSPECTIVE

From the subscriber’s point of view, training issues on Frame relay technology are less critical, but training on its test applications may be more important. These technicians are comfortable working with circuits and services focused on protocols. For example, an IS department professional may have extensive experience with the technology and the testing of X.25. However, Frame relay, unlike X.25, has no error correction, which introduces a series of testing issues. Although the technology may be similar, the test applications are different.

For subscribers, Frame relay training provides technology specifics, such as how Frame relay applies to their particular network, taking issues like CIR, DLCI connections, and link management into account.

The traditional classroom setting is still popular in many companies. If the company does not have a training department, the data communications manager should consider sending technicians on staff to an outside organization whose specific purpose is to increase workers’ comprehension or knowledge level of technology or product use. These sessions can take the form of seminars, classroom sessions, field training, video, distance learning (i.e., teleconferencing), or auditorium-style lectures. Computer-based training might also be available, which provides a self-paced environment that can cover multiple knowledge levels at the same time. As microprocessor technology and memory storage become more advanced, users are able to run complex instruction disks on their personal computers. They can take in the training at their own pace, at home, in the office, or on the road.

The Benefits of Training

Training offers a critical advantage to an organization through increased production, reduced cost, and maximized efficiency with respect to Frame relay network performance parameters. Training helps employees avoid pitfalls encountered during a new installation. It does this by increasing employee knowledge levels about Frame relay technology and then having them apply this knowledge to everyday work and even future upgrades.

In addition, training enables users to test and manage a Frame relay network from the first day of implementation. This kind of knowledge about the network decreases downtime and outages, as well as return trips to the subscriber’s premises.

The key to reducing cost and downtime of a Frame relay network is to plan and implement training before circuit implementation, because the training offers insight on potential problems before they actually occur. Subsequently, service providers and subscribers save money as downtime is reduced because the job was completed efficiently the first time. Training is an expense, but it provides a company with a return on investment through knowledgeable employees who can efficiently run a frame relay network.

CONCLUSION

Frame relay is now the main access protocol for WAN communications and will likely stay that way for the rest of the decade. But that is not the end for frame relay. The future of Frame relay lies in its capability as an access network for ATM-based services, which many consider to be the communication services of the future. Hybrid frame relay/ATM networks will provide the transition between the two networking technologies. Eventually users will run integrated multimedia applications and services over their ATM networks, making full use of technologies for which Frame relay helped pave the way.


Previous Table of Contents Next

Copyright © CRC Press LLC