[VoiceOps] Geographic redundancy

Alex Balashov abalashov at evaristesys.com
Wed Aug 12 00:39:14 EDT 2009

David Birnbaum wrote:

> I don't believe it's possible to interconnect with IP anywhere as a CLEC 
> since the PSTN infrastructure doesn't exist outside of the SS7 
> environment for all practical purposes.  (Obviously, you can peer with 
> IP but that's not the same as interconnection from a PSTN perspective).

Sure it is.  That's basically what SIGTRAN is;  SS7 mapped onto IP.

I don't know if VeriSign still offers their interconnection product 
(forget what it was called), but it used to be until very recently that 
you could get them to take your point codes and send you the signaling 
out the back side as SIGTRAN, over Internet VPN.

I've seen many DIY switches built that way, usually for cheap CLECs 
created to support the back side of some VoIP product who don't want to 
shell out for a real switch.  Common technique there is to purchase a 
SIGTRAN to H.248/MEGACO and/or MGCP signaling gateway and drive media 
gateways with that controller.  So, your physical bearer IMTs can come 
from the local ILEC to your MGWs but your SS7 can come from somewhere 
else over the Internet indirectly.

Squire makes a product that does this 
(http://www.squire-technologies.co.uk/), and I'm sure there are others. 
  Last I heard none of them do TCAP/LNP yet, though, which is obviously 
going to be something of a crippling factor if you're interconnecting in 
a pooling area (most markets at this point).  And I understand them to 
have other problems, as well.  Nevertheless, it is possible.

Level3 famously built their own signaling gateway for the Lucent TNT Max 
via H.248 in their pre-Viper platform, although I do not know whether 
the other side of that was SS7 or ISDN Q.931 or whatnot.  But it did work.

-- Alex

Alex Balashov
Evariste Systems
Web     : http://www.evaristesys.com/
Tel     : (+1) (678) 954-0670
Direct  : (+1) (678) 954-0671

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