Slashdot Mirror
British Telecom Plans to Ditch POTS Network
Samurai Cat! writes "Yahoo news has a story up regarding British Telecom's plans to scrap their traditional circuit-switched telecom network in favor of an IP-based system." Their press release has more information.
posted like 3 days ago.
http://slashdot.org/article.pl?sid=04/06/09/190247 &mode=thread&tid=126&tid=137&tid=187&tid=2 15
Only 2 days ago!
We've got ip-tel at work and it's a right bitch at times - almost like talking to someone over on a mobile. There's nothing worse than having the beginnings and endings of someone's speech cut off!
Even with QoS, ip-tel is over rated. "It should do that"... yeah, right!
Considering the "impending doom" we keep hearing about of the lack of available IPv4 numbers... one can only hope they intend to roll out their new network with IPv6. Heck, even a few class A's and NAT'ing each one to 254 usable addresses wouldn't help them...
Bring it on, BT! The power of a national telephone monopoly is insignificant compared to the power of the Slashdot effect!
"A great democracy must be progressive or it will soon cease to be a great democracy." --Theodore Roosevelt
so, like what, i need a 2.4GHz whistle for that?
it won't. BT is actually late at that game, i seem to recall AT&T Canada switching their whole network to IP based last year
British Telecom Plans to Ditch POS Network.
>1. What are the odds of this actually being pulled off?
Its quite possible. Major long distance carriers already do this. There are some technical issues, but they can be addressed, and VoIP uses bandwidth way more efficiently than a circuit switched network, so long term, the cost benefits do appear to be there.
>2. How much will this effect me, a regular dialup and telephone user of British Telecom?
As a voice user, there may be initial problems with echo, garbled voice, and delay if BT doesn't do their homework. Those problems can usually be quickly alieviated in most cases by properly employing the QoS features typically provided by high end routers.
A bigger issue is high speed modem use over VoIP, particularly if low bitrate codecs are used. Its possible that they could effectively cripple dialup ISPs without affecting voice quality in any perceptable way.. I don't know how the british communications regulations work, but here in the US, telcos can (with very few exceptions) do whatever they want to the lines so long as voice quality isn't affected (although they do have to support 9600bps data rates, who wants to surf at that speed.) Hopefully, they will keep in mind modem users, but they may decide this is a good time to force customers into broadband.
VoIP isn't as exotic as people may think--you've been using it for several years on most long-distance calls for at least part of the circuit. And all of this traffic is H.323 and not SIP.
Telus, which operates local phone service in B.C. and Alberta and cell phone service nationwide, started switching over to VoIP last year and now carries most of long-distance callls between major cities over the Internet.
1. What are the odds of this actually being pulled off?
It shouldn't be that difficult. BT's telephone network is based on System X (and it's competitor System Y). The national network is completely digital. Each customer line would be analog (unless you have ISDN) until the local exchange, where the signal would be converted into 64 Kbits digital. Advances in technology allowed a single circuit board (A4 sized) to handle up to 4 customer lines, so the entire telephone exchange for a small village could be inside a shed. BT would probably start with upgrading the national network, then do a local exchange trial in London, and then roll out across the country.
2. How much will this effect me, a regular dialup and telephone user of British Telecom?
You probably wouldn't notice anything. For each exchange, they would do a gradual switch over. They'd start by adding the new links using IP packets, test them, then allow customer calls to use them, and finally disable the old system.
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"Force" users onto broadband? Ha! I have a few relatives in the UK who would love to get broadband, and who would pay for it if it could be got for any reasonable price, but BT has dragged their heels and imposed ridiculous trigger levels for exchanges (sometimes requiring almost as many signatures as there are households). Their recent announcement that all exchanges will be converted to support DSL is way over-due; they have dragged their feet on this issue for ages (just read the Register's on-going coverage hinting that OfCom were getting more and more pissed-off with BT). This should have been a matter of policy.
Even now, after the announcement, the more remote relatives will have to wait more than a year to have their exchanges upgraded. The only other options are prohibitively expensive (satellite uplink, there is no cable service in most of the Scottish Highlands).
a.
An elderly lady phoned her telephone company to report that her telephone failed to ring when her friends called - and that on the few occasions when it did ring, her pet dog always moaned right before the phone rang. The telephone repairman proceeded to the scene, curious to see this psychic dog or senile elderly lady.
He climbed a nearby telephone pole, hooked in his test set, and dialed the subscriber's house. The phone didn't ring right away, but then the dog moaned loudly and the telephone began to ring.
Climbing down from the pole, the telephone repairman found:
1. The dog was tied to the telephone system's ground wire via a steel chain and collar.
2. The wire connection to the ground rod was loose.
3. The dog was receiving 90 volts of signaling current when the phone number was called.
4. After a couple of such jolts, the dog would start moaning and then urinate on himself and the ground.
5. The wet ground would complete the circuit, thus causing the phone to ring.
Despite my UPSes, I still find it reassuring that I can pick up my telephone at any time and get a dial tone. If I'm away from home for 5 days, and the power has been out the whole time, I can still come home and pick up the phone, expecting it to work.
:) I can't complain about 768/768 that works fine 8 miles from the telco shed.
I live in a rural area where the power co-op often doesn't know about outages until someone reports them. I'm at the end of a line, and I've had outages that have only affected me.
It's also nice to know that in an emergency, someone can come into my house and make an emergency call. It's also nice to know that I could probably make a call from another farmhouse too.
Cell phone coverage is awful here. We have three competiting technologies with very few towers each. Hooray for lack of standards in rual America! Thankfully we do have 1 MBit "Reach" (Paradyne Hotwire MVL) SDSL!
Now, I don't mind if telcos upgrade their aging first-generation DS1 and DS3 gear for the longhaul trunks. But where I live that's already been done. Lots of fibre connecting the hick towns, gotta love RTC grants!
"here in the US, telcos can (with very few exceptions) do whatever they want to the lines so long as voice quality isn't affected"
Some comment about this, ETSI SS7 ISUP (it's probably similar in the U.S) has basically three bearer capabilities:
- Circuit switched data: bits exactly the same in both ends
- 3.1 Khz: spectrum quality in this band is not affected by transit and processing in the network.
- Speech: voice inteligibility guaranteed.
The central office asks for 3.1K when a POTS line calls and the network does it's best to guarantee 3.1K. However in very long distance calls it's not always possible, because of the echo cancellers and stuff. Faxes and modems send an echo canceler disable tone, but I ignore if this works always/sometimes/...
ISDN terminals can themselves ask for whatever they need, but the network can provide or refuse the capability depending on all the transit switches involved in the call being able to provide it.
Mobile phones always use Speech.
And about VoIP, I heard Lucent dropped it's softswitch project because it just didn't work. more info anyone?
For a company the size of BT, I see the following scenario as being faily likely:
BT switch detects modem/fax carrier.
BT switch toggles from rather-compressed g.723 to uncompressed 64kbps g.711 . g.711 is is either aLaw or uLaw, depending on pond-sidedness, just like ISDN, and also just like things are switched "normally" today.
Modem communication happens normally; BT writes off increased bandwidth (vs. g.723 voice) by saying to themselves "Well, at least that one g.711 modem call didn't cost us any more line capacity than it did before, and we got to packet-switch it instead of channelize it. Cool."
Everyone's happy. And your modem doesn't even know the difference.
Kid-proof tablet..