Eircom allocating 052 in 0504 area

Big old public networks like OpenEir still contain a lot of nearly obsolete TDM switching technology and are only transitioning towards IMS for PSTN/ISDN replacement.

I know Eir made some significant investments in an Ericsson's TSS/IMS platform to replace their AXE switches at 'tertiary level' and for international gateways and so on, but AFAIK (and it may have changed), the majority (if not all) of the PSTN/ISDN was definitely still running on Ericsson AXE and Alcatel E10 switching which is all TDM-based a couple of years ago.

They're beginning to encourage customers on FTTC/H to move over to VoIP based solutions using the ATA in the modem/ home gateway to provide PSTN-like service. I would assume that once they've a significant number of customers off the old PSTN infrastructure they'll begin winding it down and putting in something more modern to support the smaller % of customers who still want old-fashioned dial tone services. That kind of thing can be done very easily with modern MSANs.

Because the number portability solution was built around that kind of technology, there would still be a lot of layers and look-ups going on to get it to all work harmoniously.

There's old tech in some of the other providers' networks too.

All I would say is that the Irish solution for number portability works quite well. I've seen far worse implementations in other countries, possibly due to limitations of the TDM hardware involved, as a lot of that gear was never really designed with the idea that there would be multiple operators. We struck it relatively lucky as the two platforms TÉ chose in the 80s were relatively flexible and the vendors continued to exist and also supported them for longer and didn't pull out of TDM tech entirely. That wasn't the case in Germany and Belgium where Siemens sold off their telecoms devision and Nokia then pretty much abandoned their ESWD switching system quite a few years ago. There's a similar issue in BT's network where System X was totally orphaned when Marconi disappeared - that prompted a faster rush to VoIP behind the scenes than it did here.

There are still some weird issues like for example you can port a number out of the PSTN to a more modern platform like any VoIP provider, Virgin, Blueface etc etc but you can't actually easily port a number from VoIP to the PSTN if it never existed on it in the first place. The numbering systems are very inflexible and baked-in. You also generally can't move numbers from one physical PSTN exchange to another, whereas that's absolutely a non-issue on modern infrastructure.

So, you've got the rather ridiculous situation that if you say move house within Dublin form exchange area to exchange area, to keep your number, you'd be better porting it to Virgin, Blueface, Goldfish etc etc as Eir won't be able to carry it from exchange-to-exchange on the PSTN as the technology can't support it. That's not unique to Ireland either, seems to be a common problem in a lot of PSTNs.

In a financial sense, it probably makes more sense to let it fade away rather than an aggressive change of technology that annoys / disrupts people.

The mobile networks are also only making the move to full IMS type solutions at the moment too. So, there's still a lot of TDM stuff in the mix. You'll see when they've IMS complete when VoLTE and WiFi calling become fully available.

When everything's moved to IMS and more modern VoIP-based platforms, it all starts to become a lot more streamlined and easier.

For a whole variety of reasons, Ireland's PSTN is has actually been a bit of a laggard in that regard too, quite a few countries e.g. Belgium have already fully completed their migration away from TDM technology.

TDM in Ireland will just quietly die out over the next few years and most people won't even notice.

I know the Alcatel E10 switches also spoke SIP too in their later versions.
There was an upgrade path to "1000 MM E10" that brought VoIP capability into them in the early 2000s. I have no idea if Eir kept their fleet of them up-to-date, but there was definitely a pathway towards all-IP networking and it was used in France.

AFAIK, you can basically replace the big local switches with IMS from Ericsson or Alcatel (Now Nokia) and morph their local concentrators into being the edge layer for an VoIP softswitch.

Given that all the operators except Sky put VoIP ATAs into their modem/router/gateway devices, I would assume the migration to VoIP for VDSL customers here will be very fast and there are a lot of them.

There’s no hard cutoff date here as yet for TDM access. I’d say it will be a fade out rather than a hard end date.

I've heard that Germany, unusually, didn't make much use of carrier pre select on the PSTN, so VDSL was sold with VoIP not with POTS access like here. I'm not sure if that was to wind down the PSTN system or did to technical limitations or regulatory limitations?

Eir seems to now sell NGA (VDSL or FTTC) with VoIP now rather than POTS. Vodafone and Digiweb had been doing that for some time already, Virgin is totally VoIP and the only one that seems to have no VoBB solution is Sky. Their home gateways don't contain any VoIP gear.

I know Vodafone automatically migrated (but didn't force) people to their VoIP service in place of POTS. Eir seems to be just selling theirs unless you specifically object to it.

There were various ways of doing it in the older tech, but in general in the system here it was all about analysing the number as it was dialled.

The old system didn't care what the number length was as the route was literally contained within the number. Even when technology moved on, that concept was largely retained and then you added more and more intelligence.

When VoIP ATAs and PBXs don't have access to the databases behind it, there's no way they can do anything other than implement a complex dial plan or use en bloc dialling like mobiles, or a time out as send.

The most likely explanation for the German setup was that the very old numbers were allocated on something like Siemens "Rotary" switches, a very old form of step-by-step switching. It didn't have any ability to perform number analysis at all, so you would have had to physically rebuild the exchange to change the numbers as each digit literally moved a mechanical component.

Those likely coexisted with digital switching for a time in the 80s / early 90s.

In Ireland, there was a big rollout of digital switching planned in about 1979 with the first of them going live in 1981. They co-existed with various eras of analogue crossbar switching, but it was generally 'modern' stuff form the 1970s, not prehistoric technology and it was largely able to do a lot of routing and integration with digital switching and computerisation.

We did have periods of time when Dublin and Cork had mixtures of 6 and 7 digit numbers as they were going through changes. The system was always capable of handling that but it was just way way easier to have them the same length.

I'm not aware of anywhere other than Germany that did it that way though.

Mostly, including in Ireland and the US/Canada etc, we just allocated a block of normal numbers to a PBX for direct-inward-dial. That was done even in the pre-ISDN days where you'd signalling going on with tones between the local switch (which could have even been electromechanical) and the PBX.

There would have only been a handful of POTS lines in the old days, or ISDN channels coming in, and the switch just sends the extension number either digitally or in the old days as multifrequency tones, and the PBX routes it to the extension.

You certainly don't have to do it as an IVR, and that isn't done in most cases in large companies here. You'd typically have a prefix for the company and extensions with regular phone numbers assigned to them. You'd save money though by not giving everyone DID. It's definitely cheaper to not rent numbering that isn't going to be used.

The PSTN was capable of doing versions of hosted PBX services (CENTREX) too. They just installed analogue or ISDN lines to each extension and the POTS switch behaved like a PBX on those lines. Bloody expensive though and rarely used from what gather, other than in very large businesses with small branch offices and so on.

From a technical point of view, you could probably have done the German approach here. I can't see how there'd have been any great technical difficulty in doing so, but I don't know that it would have been too desirable when you were calling in from abroad, or from PBXs, VoIP etc ..

These things just evolved and grew into their own bureaucratic / technocratic selves over the decades. There wasn't ever really any grand plan to be VoIP friendly as it was never envisaged when they were evolving, so I guess we are stuck with what we have.

Also, a lot of VoIP development and ATAs tend to be quite US-centric and they've very, very inflexible fixed length numbering (again for historical reasons).

The old US approach was very weird. All old area codes used there had a 1 or 0 in the middle. The switch looked for numbers with a 1 or 0 after the first digit and that's how it knew you were trying to dial long-distance and it would wait for 10 digits.

It was years later they introduced the 1-XXX-XXX-XXXX format as they ran out of area codes with a 0 or 1 in the middle.

In general the US plan is a total mess now, but it is quite VoIP friendly as the numbers are uniformly 10 digits.

The main driver in Ireland was TE used to try and keep the numbers as short as possible as they considered it more user friendly. Your finger would get sore dialling 10+ digits with a dial!! That's why we had a lot of 5-digit numbers and tons of area codes. That theory was blown away by the dominance of mobile phones (at least 4X more active mobile numbers than fixed line now)

You can write a dial plan for Ireland easily enough though. It doesn't have THAT many area codes and the numbering info is all published on comer.ie if anyone's ever looking for it.

If you were going to build a numbering system from scratch in 2018, you'd do it very differently.

Cuddlesworth wrote: »

Pretty much the story around most tech we use.

Especially stuff that had its original concept stretched into new uses... credit cards... 16 digit number + expiry date + a lot of trust thrown into the World Wide Web and we wonder why it's a big ball of fraud.