[H]omer <spam@xxxxxxx> espoused:
> Mark Kent wrote:
>
>> CallerID is a function of C7 networks. Basically, it's just about
>> moving the A-number around and presenting to the dialled party using
>> suitable signalling. Obviously, the A-number is essential for
>> billing, and the B-number for routeing, so the two are fundamental to
>> how the signalling of the PSTN works.
>
> Talking about PSTN, how will services like CallerID be affected by the
> upgrade to 21CN?
As far as I know, the present 21CN plan for the PSTN is to continue with
the existing Ericsson and Marconi switches for the existing customer
base.
>
> I'm interested specifically because I depend on services like Anonymous
> Call Rejection (the telecoms equivalent of spam filtering).
>
> I hope I don't lose my so-called "Calling Features" as a result of this
> change to the network.
Again, so far as I know, there will be no forced migration off the
existing network, so your existing services should continue to function
effectively.
>
> Also, what is your opinion of security on 21CN, and how does this relate
> to VOIP? I'm concerned that 21CN might conceivably facilitate easier
> snooping on the network.
>
I don't think that it'll make any difference, to be honest. All PSTN
switches have had "legal intercept" software built-in for as long as
they've been digital. The usage is managed by the government in all
countries, not by the operators. I suspect that some government
agencies are worried that snooping might be /more/ difficult on IP
networks than before :-)
Network security is maintained by the use of out-of-band signalling,
unlike in IP networks, where routing uses protocols which run in-band.
The "phone phreaks" of the 1970s & 1980s used to use in-band signalling
detectors in order to force particular network behaviour. This is no
longer easily possible, although that doesn't mean that the PSTN networks
are necessarily 100% secure.
--
| Mark Kent -- mark at ellandroad dot demon dot co dot uk |
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