Chapter 9. Trunking with LAN Emulation | Cisco Catalyst LAN Switching

This chapter covers the following key topics:

A Brief ATM Tutorial For engineers accustomed to working in frame-based technologies such as Ethernet, ATM can seem strange and mysterious. However, as this section discusses, it is based on many of the same fundamental concepts as technologies that are probably more familiar.
LANE: Theory of Operation Introduces the theory used by LAN Emulation (LANE) to simulate Ethernet and Token Ring networks over an ATM infrastructure. Explores the conceptual approach used by LANE and its four main components. This is followed by a detailed description of the LANE initialization sequence and the required overhead connections.
Configuration Concepts Discusses several concepts used to configure LANE on Cisco equipment.
Configuration Syntax Introduces a five-step process that can be used to configure LANE on Cisco routers and Catalyst equipment.
A Complete LANE Network Pulls together the material discussed in previous sections by examining a complete end-to-end LANE configuration in a sample campus network.
Testing the Configuration Explains several useful and important commands used to troubleshoot and maintain LANE networks on Cisco equipment.
Advanced Issues and Features Discusses a variety of advanced LANE topics such as LANE design, Simple Server Redundancy Protocol (SSRP), PVC-based connectivity, and traffic shaping.

Asynchronous Transfer Mode (ATM) has received considerable press and attention since the early 1990s. As one of the original four founders of the ATM Forum (ATMF, or The Forum), Cisco has played a significant role in ATM's development. The ATM Forum has produced a large number of standards aimed at improving the acceptance and interoperability of ATM. By 1996, several key standards were complete and available in commercial products, finally allowing network administrators to build viable networks using ATM. Today, ATM is an extremely feature-rich and high performance technology. Of the several approaches devised by the ATM Forum, LAN Emulation (LANE) has become the most popular for campus data networking.

Before getting started, two cautions are in order. First, ATM is a very complex subject don't be surprised if it takes a little while to feel comfortable with this new and complex technology. Most users find it very difficult to "ramp up" on ATM. For example, it uses a lot of geeky concepts and acronyms (you will come to learn that ATM really stands for Acronym Training Method). Second, it is impossible to cover everything there is to know about ATM in this chapter. There are obviously many books devoted entirely to the subject. Our purpose is more specific: learn as much as possible about using ATM in the real world to build LANE campus backbones (while also setting the stage for Chapter 10, which covers Multiprotocol over ATM MPOA).

However, do not despair. Believe it or not, ATM and LANE are subjects that you actually can decipher and understand. By focusing specifically on LANE, this chapter glosses over some of the murkier issues of ATM theory. By discussing it from a real-world perspective, the text avoids the labyrinth of ATM's theoretical questions and issues. By stressing the important concepts, this chapter promises to make you an effective LANE designer, planner, implementer, and troubleshooter.