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Communications The Internet

British Telecom Plans to Ditch POTS Network 138

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.
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British Telecom Plans to Ditch POTS Network

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  • this is a dupe (Score:3, Informative)

    by timecop ( 16217 ) on Friday June 11, 2004 @08:00PM (#9403533) Homepage
    posted like 3 days ago.
    • At least its a new an improved dupe. Half the posts the last time around were complaining about calling it a PSTN network instead of POTS. It's almost as if the editors kindof listened ....
  • super-DUPEr (Score:3, Informative)

    by dewpac ( 31645 ) * <matt.sappfamily@org> on Friday June 11, 2004 @08:01PM (#9403538) &mode=thread&tid=126&tid=137&tid=187&tid=2 15

    Only 2 days ago!
  • by mfearby ( 1653 ) on Friday June 11, 2004 @08:02PM (#9403547) Homepage
    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!
    • by Anonymous Coward
      What speed is your network running at? I'm fortunate enough to be in a research institute with pervasive gigabit networking. People very occasionally complain about glitchy video conference calls when the network is heavily loaded, but audio is "solved" as far as we're concerned...

      • Gigabit between buildings on site, 100mb switches in each building. Either 2mb or 10mb between each site (mostly 2mb). Heavily used by people surfing the 'net and the odd video conference. I personally don't think this is enough...
        • by Anonymous Coward
          One thing that kills is people idiotically spawning several point-to-point tools for conferences - get native multicast working, and use multicast-enabled tools.
    • by Anonymous Coward
      We use IP Telephony extensively over international leased lines and have absolutely no problem, and we're using it for critical customer-facing systems.

      VoIP is great when things are configured correctly... problem is QoS is like a chain - one weak link in the path of a packet and the whole thing is useless. Priority queueing doesn't help much if you have serialization delays or duplex misconfigurations - there are an awful lot of components to ensuring good QoS.

      Just like with network security, you don't w
      • Can't you route around? I thought that if the company is buying gigabit switches and routers you might as well get some redundancy built in to your network instead of going the old star topology.

        After all, Saddam Hussein put is entire military C3I aparatus onto his dedicated POTS telephone network. American spy planes just followed the cables... and we all know how that ended.

        TCP/IP has automatic route around capability built into that layer, so why not use it? You might even get a bigger discount buying
  • IPv6 I hope... (Score:4, Interesting)

    by Supp0rtLinux ( 594509 ) <> on Friday June 11, 2004 @08:03PM (#9403556)
    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...
    • The network is internal, not part of the Internet, so IPv4 should do - but the way Britain seems to change phone-numbering in order to cram a few more million phone users in...maybe IPv6 isn't that unreasonable!

    • Re:IPv6 I hope... (Score:5, Informative)

      by Feyr ( 449684 ) * on Friday June 11, 2004 @08:19PM (#9403660) Journal
      make that clear, there is absolutely NO shortage of ipv4 addresses.

      i just received the APNIC (asia pacific) address report for this week. here's a few fun numbers:

      60% of the allocated ipv4 space has been allocated (yes you hear it right, 60%). that leaves us with 40% still to allocate. 40% of 32 bits. now:
      2**32 = 4 294 967 296
      4 294 967 296 * 0.4 = 1717986920
      that's 1.7 billions address NOT ALLOCATED

      but here's the kick, only 50% of that allocated 60% (30% of the total) are advertised (that means routable on the internet), which in turn mean much less than that are actually used (advertised does not mean it is in use)

      • forgot to mention, the report is by APNIC, but it covers the whole internet, not just their portion
      • The other 50% of the advertised allotment are being used to hold my pants up. Believe me, you don;t want 'em.
      • Re:IPv6 I hope... (Score:5, Informative)

        by Steffan ( 126616 ) on Friday June 11, 2004 @08:46PM (#9403814)
        Actually, it's not 1.7 billion addresses. Because of the way the address space is allocated [], not every potential address is available, and that's before you take into account things like CIDR (classless interdomain routing [] not this [])
        • reguardless, they're still addresses, even if they're not all useable. but yes, there is a small percentage you could take off that 1.7 billions, that's still a lot of addresses to allocate :)
      • Re:IPv6 I hope... (Score:5, Informative)

        by Dolda2000 ( 759023 ) <fredrik@dol d a 2 0 0 0 . c om> on Friday June 11, 2004 @09:05PM (#9403911) Homepage
        That may well be, but lack of addresses is not the primary problem. The problem is that these available addresses are scattered all over the address space which makes routing much harder for each new address block that gets allocated.

        That's the greatest promise of IPv6 - ISPs will no longer have to divide their customers over a couple of hundred individual address blocks spread over distant areas of the IPv4 space - it's kinda like running defrag over the address space, only that this time it won't become fragmented again after just a little extra use.

        • ipv6 has issues. mostly policy issues but that's pretty major IMHO

          according to ARIN, under ipv6 you can no longer get allocated addresses for your own use. unless you're a big isp (tier 1) that plan to allocate addresses yourself (and lots of them).

          that means the small isp that currently has a /20 (or lower) get to renumber all of their servers if they ever want to switch to another upstream provider, which means you're pretty much fucked if your current ISP goes under or tries to screw you over (yes it h
          • Current policy at RIPE and ARIN is that every ISP can get IPv6 addresses just as easy as IPv4. Just ask and you'll get a /32. Recommended allocation to customers is a /48 (yes, 65536 64-bit subnets - 281474976710656 times the complete IPv4 address space for each enduser).

            Customers need to renumber when moving ISPs, but ISPs themselves get their own static space.

            And renumbering for endusers isn't that complicated either - only the subnet changes, you can keep the address in the /64 the same.
            • that's right but their definition of ISP is limited. for them an ISP is an entity that will make sub allocations to other entities.

              i currently work for an "ISP" that is too small to ever need to do sub allocations, but big enough that renumbering would involve about 2 months of work (with appropriate notifications to customers)

              here's the appropriate entry in the policy:

              5.1.1. Initial allocation criteria

              a) be an LIR;

              b) not be an end site;

              c) plan to provide IPv6 connectivity to organizati
      • contrary to popular beliefs, the ipv4 address space is not going to be depleted in the near term (as the values from the parent.) but using ipv6 in voip will greatly ease its deployment.

        1. ipv6 has qos built in. it will be needed for them to prioritize voice calls.

        2. it will be much easier to subnet the network by assigning an ip address for each device and a subnet for each part of the network. assinging it in ipv4 will be much difficult. for example, a /8 will give you 16.8m possible addresses.

    • Re:IPv6 I hope... (Score:1, Interesting)

      by Anonymous Coward
      I'm sure they'll still be using their own internal network for phone calls, routing over the public internet would throw reliability and quality-of-service out the door. In fact, switching to IP may do that anyhow if they aren't careful, as internet routing systems, capacity control, hardware, redundancy etc. are far less reliable than the systems used on telephone networks.

      Running out of addresses is not one of the things that is going to be a problem. The addresses used by circuit-switched digital tele
  • ...I have only two questions.

    1. What are the odds of this actually being pulled off?
    2. How much will this effect me, a regular dialup and telephone user of British Telecom?
    • by Feyr ( 449684 ) * on Friday June 11, 2004 @08:21PM (#9403671) Journal
      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
    • >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.
      • ...they may decide this is a good time to force customers into broadband.

        "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 dragge

      • (although they do have to support 9600bps data rates, who wants to surf at that speed.)

        I think it only has to be 2400bps here (UK), at least thats what I remember being told and what this suggests on page 11 (pdf) [], but I didnt read all of it :)
      • "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 ne
      • so long as voice quality isn't affected (although they do have to support 9600bps data rates, who wants to surf at that speed.)

        Believe me, there isn't a *single* low bit-rate speech codec that would allow 9600 bps rate rate. The reason is simple. Low bit-rate codecs are in the order of 8000 bps, so handling 9600 bps signals would be like being able to compress any type of signal/data. That's mathematically impossible. Even then, I'd even doubt one of these codecs would even be able to carry 300 bps modem
      • modem speeds (Score:4, Interesting)

        by adolf ( 21054 ) <> on Saturday June 12, 2004 @02:08AM (#9405180) Journal
        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.

        • Why not...

          BT detects modem/fax carrier after dial.

          BT connects one modem from a modem pool at each side's local office.

          Modem demodulates incoming data and sends it over IP (this is VoIP, after all). Modem on other end modulates IP data and sends it over a short, more reliable connection.

          Data can be compressed over the IP network, and the modem gets a high-quality line to the local office instead of the longer loop to the other modem. BT has decreased bandwith use, since it's sending raw data, not encoded
          • That'll never fly.

            You're paying BT to complete a phone call for you, not act as an ISP. When I dial a modem, I want to talk to the fucking modem that I dialed, not some reasonable-facsimile-thereof. Maybe I intend to whistle a Bell 212a carrier as part of an art project and record it with my nifty voice modem, maybe I want to yell at a housemate through the modem speaker, maybe I want my credit card transaction to happen as fast as possible rather than waiting for two handshakes to complete instead of ju
      • at BT we are advised that if a customer has less than 28000bps connection then we should put them in for an overnight gain increase

        if the gain increase does nothing we offer the customer an engineer out to check the line from the pole to their house, their sockets, junctionboxes and the rest
    • by dplong ( 316604 ) on Friday June 11, 2004 @08:42PM (#9403795)
      It shouldn't effect you at all. BT is replacing their network, not the local loop ("The switch-over will be seamless from the customer's perspective..."). IOW, you will still use your old analogue phone, and the copper wires will still connect your phone to the End Office, but from there on it will be all VoIP. A truly "end to end IP (Internet Protocol) based network," where you have VoIP phones everywhere, will take many decades to implement.

      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.
    • by mikael ( 484 ) on Friday June 11, 2004 @08:50PM (#9403840)
      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.
  • Fresh Meat! (Score:5, Funny)

    by Tackhead ( 54550 ) on Friday June 11, 2004 @08:04PM (#9403563)
    Well, we've Slashdotted damn near everything else on the planet (as well as several things off the planet). Taking on an entire country's phone system, complete with big fat pipes and uber-routers that do QoS management for 20 million people is just the next logical step.

    Bring it on, BT! The power of a national telephone monopoly is insignificant compared to the power of the Slashdot effect!

    • Speaking of which, is there access to the IP network on which the VoIP will run? It'd make a nice WAN with reasonable latency for BT customers only, and text messaging over landline may be a worthwhile idea for them....besides, it'd be fun to explore.
      • You alread can text msg over landlines in the UK. A lot of new phones have that functionality. AFAIK it is just the same as a normal phone call but with special beeps (like modems or fax machines).
  • when asked if the U.S. would like to do something similar, Bush replied, "Asia makes all the cool cell phone advancements, Europe wants to can POTS and truly enter the digital era, and we have Microsoft. Why would we want to change anything?"

    self-mod: -2 for flamebait, +2 anti-M$, result mod=0
  • cereal box (Score:5, Funny)

    by goats_in_boats ( 655991 ) on Friday June 11, 2004 @08:13PM (#9403626)
    so, like what, i need a 2.4GHz whistle for that?
  • yeah, it's a dupe. (Score:2, Informative)

    by mkavanagh2 ( 776662 )
    what it doesn't mention in the summary at least is that BT are also moving to fiber in their new developments, especially in areas like around london; while the move from POTS won't directly affect users, the move to fiber will make the intarweb a whole fuckload faster for those who are lucky enough to get it.

    unfortunately they will not be moving already laid lines to fiber for any time in the forseeable future.
  • by Anonymous Coward on Friday June 11, 2004 @08:22PM (#9403676)
    British Telecom Plans to Ditch POS Network.
  • I love innovation.
  • They wanna ditch their POTS while I wanna ditch our POTUS! :-)

  • Quick Robin... throw me the bat-dupe
  • While they're at it can they just give us all built-in broadband net access? free? if thats not worth paying taxes than fuck knows what is. Most people would use it, probably more than some other things tax goes to (ive never had a go with the parliamentary hooker!).
    • Dream on, BT is a private company now (Tah Conservative government).

      And even when they where funded by our taxes, they still wouldn't give us a decent service. Granted, it was better, but still not any good.
      • What i mean is the government says "hey hey, all yo dudes who are re-fitting your exchanges, heres some dosh, go and stick in the shit to make the broadband and do be scrimping and going spending all that cash on coke!"

        Actually that would work for the trains too: "Hey bitches, you best be fixin up them rails good, you think yo got an easy ride just because you're private? fuck that hoe, you still working for queen and country and you best buck up your ideas and stop slacking! else ER gonna come round and b
  • Break-up of ATT (Score:1, Interesting)

    by dlmarti ( 7677 )
    Ever since the original break-up of ATT inovation in
    our Telco industry has ground to a halt.

    I'm glad at least some country is reaping the benefits of technology.
    • Ever since the original break-up of ATT inovation in our Telco industry has ground to a halt.
      While I beleive that the government had no business breaking up AT&T, I must take issue with your statement.
      Here are some counter-examples to your claim:
      • Cellphones.
      • Widely-available DSL.
      • Collect calls without human-operator assistance.
      • Digital-quality vocal communications.
      • High(er)-speed modem connections.
      • I understand your point, but...

        1. Cellphones, the US cellphone technology lags the rest of the world by 5-10 years.

        2. Widely-available DSL?, only in Urban and some suburban areas. Other technologies exist with better range.

        3. Collect calls without human-operator assistance.

        4. Modem speeds? When was the last time they changed 10 years ago?

        Prior to the break of AT&T they had proposed a nationwide rollout of Fiber, think where we would be with that.
        • I wasn't arguing whether we're better off or worse off than before, or than the rest of the world.
          I was simply pointing out that innovation has occured since the breakup.

          As to your particular points:
          Cellphones did not exist prior to the breakup, IIRC.
          Neither did DSL (or, if it did, it was not available to individuals. I don't think that even the now-largely-obsolete ISDN was available to ordinary households).
          Modem speeds at the time of the breakup (in the late '70s/early '80s, much more than 10 years ago)
  • Damn tokers (Score:2, Funny)

    by DrMrLordX ( 559371 )
    It's nice to see that the UK is finally kicking its POTS habit.
  • by syrinx ( 106469 )
    I'd like to see my cell phone provider ditch its POS network..
  • by Anonymous Coward
    "We're sorry, the number you are calling is currently experiencing a distributed denial of service attack. Please try your call again..."

    Even worse if you were calling 911 or 999 or similar number...

    on an aside if you want to know the emergency numbers for different countries check out: ht ml

    nice graphic shows emergency numbers from around the world.
  • I had suspected BT stood for British Telecom (last article), but I could not find the words "British Telecom" on the article (the first time this was posted, . I could not even find out what BT stood for on the company's page (

    Its probably just me tho =).
  • so people will start saying ping instead of hello...that would be cool
  • by Anonymous Coward on Friday June 11, 2004 @11:24PM (#9404602)
    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.
  • Lifeline POTS (Score:4, Insightful)

    by green pizza ( 159161 ) on Friday June 11, 2004 @11:42PM (#9404680) Homepage
    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 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! :) I can't complain about 768/768 that works fine 8 miles from the telco shed.

    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!
    • "We have three competiting technologies with very few towers each. Hooray for lack of standards in rual America!"
      That's a pathetic attempt at a troll, maybe you should take a nap, have a meal, and try again. You'll get it eventually.
    • Thankfully we do have 1 MBit "Reach" (Paradyne Hotwire MVL) SDSL! :) I can't complain about 768/768 that works fine 8 miles from the telco shed.
      I live in Austin, Texas, approximately 2 miles from the center of the city, and I can't get anything close to this from a DSL connection. I get great cable modem service, but DSL would be 256K downstream at best. It often seems that America has forgotten the urban areas lately.
  • by satguy ( 713646 )
    BT, like Telus in Canada (and many other tier 1 PSTN carriers), are simply converting their internal circuit-switched (DS1-DS3, T1-T4) fat pipes (microwave/fibre links) to a more bandwidth-efficient packet-switched transport and routing methodology.

    The links in question are completely internal within the PSTN, and the change will be invisible to ordinary home or business subscribers - the same provision for the last mile to subscribers (POTS, Centrex, CAS or ISDN T1/E1, whatever) will remain in service fo

  • So why VoIP? (Score:2, Insightful)

    by Lars T. ( 470328 )
    VoIP makes sense when you have access to an IP network (Internet or Intranet). But when you want to packet switch telephony over a dedicate network, why the hell use IP instead of ATM?
  • I had my preferences set to ignore "stories" by this retard michael. How did that get reset?
  • A bit off the Topic

    Since we are discussing BT ,i am sure people are aware that Over the last 2-3 months we have had a price war going on.Even though the rates have crawled to 20 a month and under,a closer reading of the smallprint revelas most of these are either restricted on speed or have monthly download limits and sometimes both.

    what is the situation in worldwide,as in US,Canada,Japan,S Korea and Europe.What are the usual charges per month and how good is the service?
  • Routing lots and lots of seperate IP channels, the number of ADSL customers in the UK is vast, and yet every single one has his or her data connection routed over BT's network to there ISP...

    Naturally it would be more efficient to off-load that data onto the internet before routing it accross there networks, definately could be a plus for P2P applications if they started using hop-count as a way of discriminating against peers, but the removal of low latancy circuit switched technology might cause more pro

I came, I saw, I deleted all your files.