3Com CoreBuilder 9000, User Manual

Page: 385 / 468

LAN Emulation in the CoreBuilder 9000 ATM Enterprise Switch 385
When the LES of an ELAN and the LECS are in separate CoreBuilder units,
proceed as follows:
1 Use the Update ELAN Parameters via LECS command in the CoreBuilder
unit that contains the LECS to update the ELAN parameters in the LECS
database. (For more information, see “Update ELAN Parameters in LECS
Database” on page 249.)
2 Use the Update ELAN Parameters via LES command in the CoreBuilder
unit that contains the LES to update the ELAN parameters of the LES. (For
more information, see “Update ELAN Parameters in LES Database” on
page 281).
The CoreBuilder 9000 ATM Enterprise Switch supports the definition of
up to 380 ELANs in one LECS; 16 LANE services can be implemented in
one switch.
Connecting a LEC to
an ELAN
As mentioned in “LAN Emulation Configuration Server (LECS)” on
page 377, the LECS in the CoreBuilder 9000 enables a LEC to join an
ELAN to obtain a LES address. The LEC connects to the LECS within one
of the CoreBuilder 9000 ATM Enterprise Switches in the ATM cloud
through the standard addressing protocol. This is described in more detail
in the next section.
When the connection of LEC to LECS is established, a configuration
request must be passed and a configuration response must be received.
The LECS then identifies an appropriate LES using the search policies
described later and transfers the LES address to the LEC. A LECS database
within the CoreBuilder 9000 stores the network structure.
LECS Address Access A LEC can access the LECS address in two ways: by ILMI or directly to the
LECS “well-known” address. If the ILMI channel (VPI/VCI = 0/16) is
connected between LEC and LECS and if the LEC device supports
enquiries of the ILMI MIB “atmSrvcRegistryGroup”, then it is the
preferred channel of communication. If not, then the LEC communicates
with the LECS by the LECS “well-known” address.
The type of communication between LEC and LECS is set by management
via a parameter called “LECS via ILMI”. For communication by ILMI, this
parameter is set to enable. Otherwise it is disabled.