Emulated LAN Connections 12-7

 

Q 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

The LECS assigns individual LAN Emulation clients to different emulated

Configuration Server

LANs. When a LEC initializes, it establishes connection to the LECS. Based

(LECS)

on its own programming, configuration database and information

 

provided by clients, it assigns any client which 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 which it is representing (ELAN name).

 

 

Emulated LAN

Emulated LAN components communicate with each other by means of

Connections

VCCs. Control signals and data transmissions are handled by separate

 

VCCs: Control VCCs and Data VCCs.

Control VCCs

The control VCCs carry control traffic such as LE_ARP requests and

 

responses. On initialization, control VCCs are established between LEC

 

and LES (bi-directional control-directVCC and control-distributeVCC) as

 

well as a bi-directional configuration VCC between LEC and LECS.

 

Characteristics of the control VCCs are summarized in the following

 

table.

Table 12-1Control VCCs

VCC Name

From/To

Information carried

Initialized by

Duration

 

 

 

 

 

Configuration

LEC<==>LECS

LEC requests and receives

LEC

While needed

 

 

configuration information

 

 

 

 

from LECS, including LES

 

 

 

 

address

 

 

 

 

 

 

 

Control-direct

LEC<==>LES

LEC sends and receives

LEC

Membership of

 

 

controls from LES, including

 

LEC in ELAN

 

 

LE_ARP information

 

 

 

 

 

 

 

Control-distribute

LES==>LEC

LES distributes control traffic

LES

Membership of

 

 

to LECs, including LE_ARP

 

LEC in ELAN

 

 

information

 

 

 

 

 

 

 

Page 154
Image 154
3Com 7600 manual Emulated LAN, Connections, LAN Emulation, Control VCCs