On 4/02/2016 11:52 AM, David Lochrin wrote: > This thread follows on from "NBN backup service"... > > On 2016-02-02 12:14 Paul Brooks wrote: > >> No - call routing and handling will be done by the ISP's softswitch, likely >> to be located in the nearest capital city - I doubt there will be any >> voice-handling infrastructure in a node or POI, just effectively an Ethernet >> tunnel between NTU analog port and softswitch through the >> backhaul-POI-NNI-CVC-AVC-NTU chain. > My understanding is that an ISP must have a connection to every POI which > services an area containing their customers. A POI services a "connectivity > service area" or CSA and all communication within a CSA is done at OSI > level-2, with ADSL / VDSL between the nodes & users. > > So someone with existing ADSL & VoIP services doesn't need to change anything > much when they migrate to an FTTN-based NBN service except that they'd have > to configure a properly allocated VoIP telephone number for communication > with other telephone users on the national network, and perhaps some other > minor configuration changes. Most probably they'll be replacing their ADSL modem with a VDSL2-capable modem, so they might need to do some re-working of the config in the new modem, but essentially correct - the number shouldn't need to change, and however they are connecting to the VoIP service is likely to be very similar.
> > But what do traditional POTS users do when the local NBN network is fully > cutover and the exchange effectively closes down? Will they each be issued > with an NTU, or do the kerbside nodes contain analogue signal converters? For FTTN they'll each need to obtain a VDSL2-capable modem, from their RSP or possibly from a retail store, which complies with/is certified for the NBN infrastructure. Most of these also include an analogue voice port and VoIP software inside, which effectively replaces the analogue socket on the wall. Ideally the RSP will program up the VoIP module in the router to talk to the RSP's softswitch, and the user will just unplug their analogue handset from the wall, and plug it into the voice port on the modem/router. Alternatively they might get a stand-alone VoIP SIP adapter, and plug their handset into that. Note also that the ISP need not be the same as the voice RSP - the VoIP call might pass through the ISP to a different service provider providing the telephone service. The telephone RSP doesn't need a connection to any POI or the NBN anywhere. > > An ISP which doesn't connect to all 121 or so POIs must have a connection to > a service provider which can route voice calls to / from users in those CSAs. > So how does an ISP decide how to route a call when the called number may be > with them, with a user on a different ISP in the same CSA, or with a user in > a different CSA to which the ISP has direct access, or another CSA altogether? The same way they do now - they have an upstream connection to a voice call provider who can direct the call onwards - locally, nationally, and globally. If the call is directed to another number that is not directly with that RSP, the RSP's softswitch passes it upstream to be handled. There are two national call routing databases - the ACMA register of which number ranges have been allocated to which networks/providers, and the ported number register that holds the exceptions. Eventually the call gets passed up to a voice network with hooks into the national call routing databases, which routes the call to the provider servicing the number being called - which somehow makes the destination phone ring. See https://www.thenumberingsystem.com.au/#/number-register/search (you can download the entire range allocation database at bottom right) and look up your own number to see the original carrier the number was allocated to. > > Is there some sort of online directory which maps telephone number, CSA, ISP, > and level-2 address? Who maintains it, NBNCo? As above - ACMA maintains the directory mapping telephone number to provider/network. Its up to each provider to work out the rest of how to direct an incoming call to make their own customer's handset ring, whether its on NBN, copper, fibre, wireless, or wet string. > > The more I think about this the more questions arise. For example, the > potential for maintenance problems and "finger pointing" seems quite high. > And it may be difficult to define enforceable service standards. There are already enforcible service and call quality standards, put in place way back when service/network competition was introduced (think calling from fixed to mobile, or copper to HFC voice). Adding the NBN into the mix as just one more possible transport method doesn't change that aspect at all - or the propensity for finger-pointing, which was already fairly high before the NBN came along! Paul. _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
