Avaya M770 - page 203

Chapter 13 LANE Services
Avaya M770 ATM Switch User’s Guide 183
Proprietary resilient LECS
The proprietary resilient LECS provides automatic redundancy for the active LECS,
by continuously monitoring the status of all resilient LECS.
From the list of available resilient LECSes on the network, the selection of the
“active LECS” is done by a process of election. To carry out this election, all ATM
switches must be M770s, and ILMI between them must be enabled.
Note: If you are not planning to use PNNI routing or want the switches in the third
party environments to host resilient LECS, then you should contact Avaya
Technical Support. They can provide you with further information on what manual
configuration is required, depending on your third party switch, to get LECS
redundancy on your M770 ATM Switches.
A proprietary protocol is used to provide automatic LECS redundancy with the
following method of:
— establishing an active mesh of SVCs between the switches hosting resilient
LECSes.
— discovering and advertising resilient LECSes on the network.
— propagating the address of the “active LECS” and of the resilient standby
LECSes.
Note: To ensure that a standby LECS can smoothly take over the running of the
network, should the active elected LECS fail, it must be configured with the same
LANE services information as the active elected LECS.
There is no checking of database consistency between switches that are hosting
resilient LECSes.
The status of the elected active LECS is continually monitored by the other resilient
LECS. Should the elected active LECS fail, another election process will take place to
elect a new active LECS from one of the resilient LECSes. Providing all resilient
LECS have the same database configurations then there should be no disruption in
the working of LANE services in the ATM network.
If your switch is hosting a local LECS then you can view the details of other resilient
LECS on the network. For more information about displaying details of other
resilient LECS on the network, see Displaying a resilient LECS election candidate in
Chapter 14 Managing t he LECS.
The example below shows the M770 ATM Switch across a third party switch. It is
recommended that if you have a M770 ATM Switch connected via a third party
switch, then that M770 ATM Switch should not host a resilient LECS.