MLSM messaging guide?

[RichardDDA]

Hi there,

I'm working on a system that has Cisco ICM version 4.1 Peripheral Gateways interfacing with SCCS 4.2 via a meridian link interface.

We're having a few problems with phantom calls getting stuck in ICM and I'd like to examine the progression of the call through the raw meridian link messages (to see if MLSM is forgetting to tell ICM that a call is disconnected intermittently or if ICM is ignoring some of the messages)

I can see through the logs on ICM that the meridian link messaging is occurring and here's an example of a few of the messages I see:

MLK: RREQ
MLK: COFF
MLK: STCHG
MLK: ANSI
MLK: RELI

I can guess that COFF is call offered, ANSI answered?... RELI released.... but considering that there are sometimes 40 or 50 calls per minute routing through this beast - how do I relate these messages to a specific call? Is it the LCID in the MLK message that ties the various entries together, or something else?

Any help much appreciated thanks!

 

[jadiebear]

Richard,

Like you said, it's not an easy task to decipher Meridian Link messages. I used to work for Nortel and worked on this a lot and understand what you meant. Luckily you looked at the PIM trace from ICM which already decoded the Meridian Link raw message (in hex) which completely unreadable if you don't have the Meridian Link spec.

Answer to your questions:

RREQ = Route Request
COFF = Call Offered
STCHG = Status Change
ANSI = Answer Indication
RELI - Release Indication

It's correct. You can trace an individual call by LCID. However pay attention on PosID as well and status of the call on each message to see if it makes sense.

You can post an example of messages that you do not understand and I'll try to help.