Emulated Lan Components - 3Com CoreBuilder 7000 Operation Manual

138 C 7: LAN E
HAPTER
Emulated LAN
Components
V 1.0
MULATION ERSIONS AND
stacks (i.e. APPN, Net BIOS, IPX, AppleTalk, etc.) as if they were
running over a traditional LAN. Since the protocol stacks are
communicating with the MAC driver (in layer 2), LANE services has to
offer the same MAC Driver service primitives, thus keeping the upper
protocol layers unchanged.


Emulated LANs (ELANs) — In some network environments there is a
need to configure multiple, separate domains within a single network.
An emulated LAN or ELAN allows for a group of devices to be logically
analogous to a group of LAN stations attached to a LAN segment.
Since multiple ELANs are logically independent, a broadcast frame
originating from a member of a particular ELAN is distributed only to
the members contained within that ELAN.


Interconnection with Existing LANs — In addition to the services
previously mentioned, LANE also provides for connectivity with
LAN-attached stations. This includes connectivity from ATM to LAN
and from LAN to LAN across ATM. MAC layer LANE is defined in such
a way that existing bridging methods (both transparent and source
route bridging) are easily employed.
LANE also provides an interface for which to provide these services. LAN
User to Network Interface (LUNI) was developed for this purpose. A more
detailed description is found later in this chapter.
LAN Emulation is implemented as a set of connection services collectively
called an emulated LAN (ELAN). Each ELAN is composed of a set of LAN
Emulation Clients (LECs) and either a LANE Configuration Server (LECS),
an LANE Server (LES), or a Broadcast and Unknown Server (BUS) which
are collectively grouped as LANE Services. LUNI is the protocol used to
communicate between the LANE Clients and the LANE Services.
Figure 44 shows the relationship between LUNI and LANE Clients and
LANE Services.
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