3-4Configuring an Emulated LAN3.3 Emulated LAN OperationThis section describes the operation of an ELAN and its components from thepoint of view of a LEC. The operation of an ELAN may be divided into threephases:1. Initialization2. Registration and Address Resolution3. Data TransferELAN components communicate with each other using ATM connections.LECs maintain separate connections for traffic control functions and datatransfer. The following connection types are used by the LEC when operatingin an ELAN:• Configuration-Direct Connection: a bidirectional point-to-point VCCset up by the LEC to the LECS.• Control-Direct Connection: a bidirectional point-to-point VCC set upby the LEC to the LES. This connection must be maintained for theduration of the LEC’s participation in the ELAN.• Control-Distribute Connection: a unidirectional point-to-multipointVCC set up by the LES to the LEC. This connection must be main-tained for the duration of the LEC’s participation in the ELAN.• Multicast-Send Connection: a bidirectional point-to-point VCC set upby the LEC to the BUS for sending multicast data to the BUS. The LECmust attempt to maintain this connection while participating in theELAN.• Multicast-Forward Connection: a unidirectional point-to-multipointVCC set up from the BUS to LECs participating in the ELAN. ThisVCC must be established before a LEC participates in an ELAN. TheLEC must attempt to maintain this connection while participating inthe ELAN.• Data-Direct Connection: a bidirectional point-to-point VCC set upbetween LECs that want to exchange unicast data traffic.For the following discussion, please refer to Figure 3.2.
