3Com 5000 ATM manual 10CHAPTER 2 LAN Emulation Overview

2-10CHAPTER 2: LAN EMULATION OVERVIEW

LECS Connection The LEC must determine the ATM address of its LECS and establish a connection to the LECS. The LEC attempts each of the following methods, in the order provided, to connect to its LECS:

1Uses a locally configured LECS ATM address.

2Queries the ILMI Service Registry MIB of the attached ATM switch for one or more LECS ATM addresses.

3Uses a predefined “well-known” LECS ATM address.

The use of another LANE 1.0 method of LECS connection, a PVC (Permanent Virtual Circuit) connection over VPI/VCI 0/17 (Virtual Path Identifier/Virtual Circuit Identifier), is not supported by the ATM Backbone SwitchModule.

The LEC proceeds to the Configuration stage when it establishes a connection to the LECS.

Configuration During the configuration stage, the LEC:

1Sends a Configuration Request, containing identifying information about itself, to the LECS.

2Receives a Configuration Response from the LECS containing the ATM address of the LES to which the LEC is assigned, as well as emulated LAN parameters such as ELAN type, frame size, and ELAN name.

Joining During the Joining stage, the LEC:

1Connects to the LES and sends a Join Request containing LANE parameter settings that were locally configured (manual mode) or obtained from the LECS (automatic mode).

2Receives a Join Response from the LES indicating whether the LEC is accepted onto the emulated LAN controlled by that LES.