3Com CoreBuilder 9000, User Manual

Page: 386 / 468

386 C
HAPTER
15: LAN E
MULATION
The ILMI channel can be continuously verified (polled) so that the
network administrator knows if the channel has failed. (For more
information, see “Display ILMI Channel Polling Status” on page 128.) In
that event, the network administrator needs to disable the “LECS via
ILMI” parameter.
LECS Connect Phase
During the LECS Connect phase, the LEC establishes its connection with
the LECS. If use of the LECS is not required, a LEC may skip this phase.
The mechanisms that are used to locate the configuration service are as
follows, in order:
1 Get the LECS address via ILMI.
2 Use the well-known LECS address.
3 Use the LECS PVC (not supported by the CoreBuilder 9000 ATM
Enterprise Switch).
LECS Search Policy
When a LEC requests to join an ELAN, it can supply the following
information to assist the LECS in finding the appropriate LES:
The ATM address of the LES with which it wants to communicate over
an ELAN
The MAC address of the LES with which it wants to communicate over
an ELAN
The ELAN name of the ELAN it wants to join
Accordingly, there are three possible ways (search policies) that the LECS
can try to identify an appropriate LES for the LEC:
1 The LECS searches for an ELAN whose LES has the required ATM address.
2 The LECS searches for an ELAN that contains the LES with the required
MAC address.
3 The LECS searches for an ELAN with the required ELAN name.
These three policies are tried by the LECS in order. If one does not
succeed, the next is tried. The search policies can be displayed by
management.