3Com CoreBuilder 9000, User Manual

Page: 377 / 468

Emulated LAN Components 377
Broadcast and
Unknown Server
(BUS)
The BUS is the LE connection service that handles ATM traffic other than
direct transmissions between LECs. It handles the following:
Data sent by a LEC to the broadcast MAC address
All multicast traffic
Initial unicast frames that are sent by a LEC before the data direct
virtual connection to the ATM address has been resolved
Unknown traffic
All broadcast, multicast, and unknown traffic to and from a LEC passes
through a single BUS.
The BUS also handles ATM connections and manages its distribution
group.
LAN Emulation
Configuration Server
(LECS)
The LECS assigns individual LAN Emulation Clients to different Emulated
LANs. Based on its own programming, configuration database, and
information provided by clients, it assigns any client that requests
configuration information to a particular Emulated LAN service by giving
the client the LES’s ATM address. This method supports the ability to
assign a client to an Emulated LAN based on either the physical location
(ATM address) or the identity of a LAN destination that it represents
(ELAN name). LECs obtain information from a LECS using the
configuration protocol.