[asterisk-ss7] ss7 newbie

Matthew Fredrickson creslin at digium.com
Wed Aug 13 10:49:26 CDT 2008

Sriram wrote:
> Hi
> Thnks for the reply...So say if i want 120 channels over ss7 
> signalling...will the telco give me 4 E1s and 1 separate E1 for ss7 
> signalling or will the ss7 be in one of the 4 E1s itself..?

Sometimes.  It depends on what you negotiate with the telco you're 
interconnecting with.  Some of them like to waste an E1 on a single 
signalling link though.  And even stupider ones waste a single E1 on two 
signalling links.  It seems ridiculous to mandate redundant signalling 
links and have them running over the same E1 (Don't ask, I had somebody 
come to me having to deal with that).

But in any case, you can negotiate with them how you would like to set 
it up typically.

> Do i have to just plug in those 4 E1s directly into the TE420P and 
> install libss7 ? thats it ?

Yes :-)  And configure it.

> Also please tell me what are the advantages of ss7 over PRI in terms of 
> 1.call handling capacity 2. connectivity 3. reliability ..

If you need answers to that question, you probably need to research more 
into what SS7 is.

Typically, you have a more reliable link since you can have redundant 
signalling channels.  The protocol also supports a lot more bearers per 
signalling link than you can do in PRI (or even NFAS PRI).

Matthew Fredrickson
Digium, Inc.

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