[asterisk-ss7] dpc and adjpc

Matthew Fredrickson creslin at digium.com
Thu Oct 18 11:18:32 CDT 2007

Eric Huang 黃富鴻 wrote:
> Hi Matthew and all ,
> I am still trying to find the problem about SS7 signaling route. Now I
> am using SS7 protocol analyzer to check further my problem.
> my scenario:
> Signaling (16):
> Asterisk (PC 100) <-> MGW (PC 1001) <-> MSS (PC 1000)
> Circuit (1-15, 17,31):
> Asterisk (PC 100) <-> MSS (PC 1000)
> Asterisk's config in zapata.conf:
> pointcode = 100
> adjpointcode = 1001
> defaultdpc = 1000
> MSS and MGW have configured routing correctly to see Asterisk (PC
> 100). I have seen STLM between PC 100 and PC 1000, but CGR from PC 100
> to PC 1001 have no response back. I guess it's some problem with
> routing. I am in the stage to link up MTP3 between PC 1000 and PC 100.
> No successful ISUP messages yet in my scenario. Because I am really
> new to SS7, hard for me now to describe/identify the problem.

I have seen this before.  In the ITU SS7 specs, there are two types of 
exchanges (in reference to bringing them up for the first time).  There 
are exchanges that require a reset of the circuits when you bring the 
link up (Type A) and there are those that require no such reset before 
starting to make calls (Type B).  I think perhaps a next logical step is 
to see what happens when you try to place a call out on the link.

Matthew Fredrickson
Software/Firmware Engineer
Digium, Inc.

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