On 10/01/2018 4:12 PM, David wrote: > On Wednesday, 10 January 2018 2:34:20 PM AEDT Paul Brooks wrote: > >> All of these [voice transport protocols] are part of the PSTN, and the >> traditional telephone number addressing is the Universal Voice Glue that >> makes it all work together relatively seamlessly, and lets someone on a POTS >> line call someone on IP line without having to be aware of what technology >> the receiver is using at that moment. Not quite irrelevant!. > However IP-based voice connections will be in a huge majority when the NBN > finishes its rollout, probably enough to warrant a strategic rethink. Call > routing based on POTS number, as currently done by the carriers, logically > duplicates a function which could, in principle, be done by the IP (i.e. NBN) > network. Surely it should be possible to integrate the IP and remaining POTS > networks so the whole system is more efficient and way less cumbersome. I think what you're looking for is RFC 6116 ENUM - a DNS lookup of a telephone number to a URI such as a SIP address, and RFC 5067, RFC 5526 "Infrastructure ENUM", and RFC 3824 "Using E.164 number with SIP".
Check https://en.wikipedia.org/wiki/Telephone_number_mapping for an overview. However, having a lot of IP-based access lines is not the same as having a world, or even a country, where everybody can be interconnected end-to-end with a VoIP call. Considerations like lawful interception, metadata retention etc require the call to pass through the RSPs on the way through, it can't just take a shorter routing path direct IP-to-IP or neighbour-to-neighbour like nirvana of IP telephony might imagine, as it might occur within a single campus like a corporate office, so there's little real routing efficiency to be gained. Sure routing by POTS number duplicates a function that IP networks could do, for calls to another IP line - but the telephone service transcends IP and exists above IP, in an application layer, and needs to work across all the other technologies as well - so it should use an addressing and routing system appropriate to its layer, not be limited by the shoehorning it into a lower layer. ENUM is the translation method from one to the other. The reality is that a large number of calls to and from an IP-enable voice line won't have another IP-enabled voice line at the other end, they'll hit a gateway in the middle. Incoming calls from international locations, corporate offices and call centres (generally on ISDN-PRI-based PABXs ), mobile networks and conventional POTS lines will all still need to use a E.164 telephone number to reach the consumer. From the consumer making an outbound call, its still actually easier and quicker to punch in a telephone number than to tap out a long SIP URI, and devices need a much smaller keypad too, and for those using a directory where they select a name or a face (like a mobile handset contacts directory) it doesn't really matter if the underlying entry for the picture is a number or a SIP URI. So from a usability perspective, the conventional telephone number is still actually easier to use. (Also, re the NBN - The NBN is an Ethernet Layer 2 network, not an IP network, and consists of 121 disconnected islands rather than a national network, so national VoIP interconnection can't and shouldn't be done within the NBN anyway!) cheers, Paul. > > >>> I see, I'd assumed the mandatory requirement to publish a PLNR ("Ported >>> Local Number Register") file was intended to allow all carriers to route >>> calls directly to the carrier currently holding a ported number without >>> going through the donor carrier. But the whole idea might be suffering >>> scability problems now. >> That is the idea - but also, even interconnect arrangements are bilateral as >> well. 'Your' carrier may not even have a bilateral network interconnect >> directly with the final destination network hosting the number, and may have >> to route the call through a third network who will provide the transit >> connectivity (who might or might not be the original donor carrier) - who >> will do a second lookup of the PLNR in the process to work out which >> direction to forward the call to. > Out of interest I downloaded the full "EnhancedFullDownload.csv" file (81.4 > Mbytes!) from > https://www.thenumberingsystem.com.au/#/number-register/search This shows > the allocated and current holders of the entire POTS numbering range, but at > a quick look I couldn't see any individual numbers, just ranges. > > It's all something of a mystery, I suppose there's probably a degree of > ad-hocery going on... > > David L. > _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
