Lucent Technologies CAJUN M770, User Manual

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Cajun M770 ATM Switch User’s Guide 241
Appendix D
Components in LANE Services
This chapter gives a basic overview on the components of LANE Services.
LAN Emulation
The principles of LAN Emulation
LAN Emulation (LANE) enables legacy LAN applications to use an ATM transport
medium transparently. Therefore, end-stations on existing Token Ring and
Ethernet LANs can communicate with ATM end-stations.
Components of LAN Emulation
• LAN Emulation Client (LEC)
Every device on an ELAN has one or more LECs. This interfaces with the ATM
network and performs most of the work of LAN emulation.
• LAN Emulation Server (LES)
There is at least one active LES (which may be a part of a distributed LES)
allocated to each Emulated LAN (ELAN). The LES maintains a list containing
both the LAN address (MAC address) and/or the route descriptor, and the ATM
address for every LEC that is active on the ELAN.
• Broadcast Unknown Server (BUS)
There is only one active BUS (which may be a part of a distributed BUS) on an
ELAN. The BUS is normally part of the same software module as the LES and
provides the ELAN with broadcast and multicast facilities. It has direct
connections to every LEC on the ELAN.
• LAN Emulation Configuration Server (LECS)
There is only one active LECS (however, you may have a number of standby
LECS) on the network. The LECS maintains a list of all LESes. The LECS
provides each LEC that contacts it with the ATM address of the LES hosting the
ELAN that it should join. The LECS is usually located locally or remotely at the
following ATM Forum Well-Known Address (WKA)
47.00.79.00.00.00.00.00.00.00.00.00.00.00.a0.3e.00.00.01.
Communication on an Emulated LAN
It is the LEC in an ATM device that will perform most of the work of LAN
emulation. To do this it must join an ELAN.
Discovering the ATM address of the LES
Before a LEC can join an ELAN, it typically gets the ATM address of the LES from