Stinger® ADSL 48-Port Annex C LIM Guide
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Configuring LIM and LIM Port Redundancy
You can configure LIM and LIM port redundancy for more than one kind of LIM in a single
Stinger chassis. For example, a single Stinger unit with both asymmetric digital subscriber line
(ADSL) and symmetric digital subscriber line (SDSL) LIMs can be configured with a spare
ADSL LIM and a spare SDSL LIM.
Overview of LIM and LIM port redundancy
A spare LIM can replace an entire failed LIM or a single failed port. LIM redundancy transfers
all logical connections from a failed LIM to the spare LIM. LIM port redundancy transfers the
logical connection from a particular failed port on a LIM to the corresponding port on the spare
LIM. The remaining ports on the spare LIM remain available to provide additional LIM port
redundancy.
Each LIM to be used as a spare must have either a path selector module (PSM) or copper loop
test (CLT) module plugged in behind or next to it in place of a line protection module (LPM).
All other LIMs must use an LPM with port redundancy (LPM-RP) for line protection.
Note:
Some older Stinger systems are equipped with an interface redundancy module (IRM)
located behind the spare LIM, and LPMs with redundancy (LPM-R) located behind the LIMs
to be backed up. In this case, additional configuration steps might be needed. For more
information, see “LIM redundancy with IRMs and LPM-Rs” on page 2-6.
Configuring LIM redundancy
LIM redundancy provides a one-to-one backup function for LIMs. Each type of LIM to be
backed up requires a spare LIM with a PSM or CLT module plugged in behind or next to it. For
example, a Stinger FS configured with 14 ADSL 24-port LIMs can be set up with the
following module pairs:
•
13 pairs each consisting of an ADSL LIM and an LPM-RP
•
1 pair consisting of an ADSL LIM and a PSM or CLT module
The resulting system has 13 active ADSL LIMs and one spare that can be substituted for any
one of the 13 LIMs if a failure occurs.
