Lucent Technologies M770 - Manual (Page 41)

Cajun M770 ATM Switch Manager User’s Guide 31
Chapter 7
Managing LANE Services
This section explains how to manage the LAN Emulation (LANE) services provided by
the Cajun M770 ATM Switch. It includes the following topics:
•
Resilient LANE
• Choosing the LES Address for a LEC
• Setting Up the LECS
For more information on LAN Emulation, refer to LAN Emulation in The Reference
Guide.
Resilient LANE
The Cajun M770 ATM Switch, in addition to LANE 1.0, supports proprietary
redundant LANE services.
For more information on Resilient LANE, refer to Proprietary Redundant Services in The
Reference Guide.
Choosing the LES Address for a LEC
When a LEC starts up, it connects to the LECS as usual. The LECS may have several
different possible LESs for a particular ELAN (if it is in distributed mode), so it must
decide which one to give to the LEC. It is possible to configure one of three possible
options:
• Round Robin - Each LES address is used in turn.
• Group Address - Every LES uses the same address. When a LEC requests that
ELAN, it is given the “common” address of the LESs. The LEC connects with the
“nearest” switch via routing.
• Best Match - The LES address supplied is the one which best matches the ATM
address of the LEC (and so should also be the “nearest” LES in many cases,
especially if a hierarchical addressing scheme is used).
Round Robin is the default because it will normally guarantee an even spread of clients
amongst all possible LESs. However, it is preferable in some cases to use Group
Address or Best Match.
Group Address usually gives the fastest recovery time. If a LES fails, it normally takes
the LECS at least 90 seconds to time out on the address of this LES. If the scheme used
is Best Match, any clients applying to join the ELAN during this period will be directed
to the failed LES address. However, if the scheme is Group Address, then the address is