3Com CoreBuilder 9000 User Manual page 387

LAN Emulation in the CoreBuilder 9000 ATM Enterprise Switch 387
Connecting LEC to LES and BUS
LES and BUS connections were presented in "Emulated LAN
Connections" on page 378. After the initial registration of the LAN
Emulation Client (LEC) with the CoreBuilder 9000 ATM Enterprise Switch,
the LEC sets up the Control Direct VCC, a direct bi-directional
point-to-point connection with the LES. In addition, the LES adds the LEC
to its Control Distribute VCC, a uni-directional, point-to-multipoint
connection.
The LEC then interrogates the LES for the BUS ATM address and sets up
the Multicast Send VCC, a direct bi-directional point-to-point connection
with the BUS. In addition, the BUS adds the LEC to its Multicast Forward
VCC, a uni-directional, point-to-multipoint connection. These
connections enable direct communication to and from the LEC to the LES
and BUS, as well as connections for flooding data (that is, connections for
Multicast, Broadcast, and Unknown data) to all the LECs in the same
Emulated LAN (ELAN).
Figure 25 LES and BUS Connections