3-6Configuring an Emulated LAN3.3.1 InitializationUpon initialization, LEC1 obtains its own ATM address via address registra-tion. LEC1 obtains the address of the LECS in one of three ways: via manualconfiguration, via the “well-known” address defined by the ATM Forum’sLANE standards (47.0079.00.000000.0000.0000.0000.00A03E000001.00), or viaPVC (0,17).Once it knows the location of the LECS, LEC1 establishes a configuration-direct connection Ê to the LECS. When connected, the LECS provides LEC1with the information necessary to connect to the ELAN it wishes to join. Thisinformation includes such parameters as: the ATM address of the ELAN’sLES, the type of LAN being emulated, the maximum packet size, and thename of the ELAN (engineering, for example). This configuration informa-tion is contained in a configuration file that must be built and maintained bythe network administrator.NOTE: Detailed information about the LECSconfiguration file may be found in Section3.4.1.3.3.2 Registration and Address ResolutionAfter obtaining the address of the LES, LEC1 establishes a control-direct con-nection Ë to the LES. The LES assigns LEC1 a unique identifier, and LEC1registers its own MAC and ATM addresses with the LES. (The LES maintainsa table containing the MAC addresses and corresponding ATM addresses ofall members of the ELAN.) At this point, LEC1 has “joined” the ELAN.The LES then establishes a control-distribute connection Ì back to LEC1.Connections Ë and Ì can now be used by LEC1 to send LAN EmulationARP (LE_ARP) requests to the LES, and receive replies.LEC1 now sends an LE_ARP request to the LES to get the ATM address of theBUS corresponding to the broadcast MAC address (FFFFFFFFFFFF). The LECthen establishes a multicast-send connection Í to the BUS. The BUS respondsby setting up a multicast-forward connection Î to the LEC.At this point, the LEC is ready to transfer data.
