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Sprint Moves Phone Network to IP
Ryan Barrett writes "Sprint announced that it has 'begun transforming its telephone network so voice calls are transmitted in packets.' AP article here. Combined with a recent /. story about Telus doing the same thing, this sets an interesting precedent. Many telcos already use packet-switching to handle a significant chunk of their calls. Is this the beginning of the end for circuit-switched networks?"
A friend who used to work for Nortel (didn't many) mentioned this. Worldcom did most of their long distance stuff on top of IP6.
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I really can't see an end to circuit switched networks any time soon. The switch to Packeted data is fine for most commercial traffic, but there are a few areas that will continue to require "locked in" circuits as opposed to packet buffering systems.
There is a lot of value in the use of packetized data. More "lines" over fewer trunks is just one of them, and for your average, everyday user, they will not notice the difference.
On the other hand, certain timing based encryption schemes will have to remain on locked in circuits to function. The latency caused through the use of packet buffering regardless of how slight, may be enough to cause a "handshake" failure, or just spew unintelligable garbage.
Of course, as encryption systems become more and more robust the need for "hard lines" will start to dissipate.
I for one welcome our new packetized telephone overlords...
krystal_blade
It will be easy to motivate our fellow man; there is hardly anything people treasure more than not being annihilated.
The network will still be switched at a local level, I suspect (even if the future telephone exchange, instead of switching analogue circuits, works more like an Ethernet switch). With so much copper going from the home/office to the exchange, it's likely to continue to be in use for the last mile for some time to come.
Trunk switching has been multiplexed for decades already. Previously, it might have been multiplexed by FDMA (frequency division), and now it looks like they are moving to IP based (or similar) to route calls through exchanges. The end user won't notice the difference. It's unlikely that the call routing will be done over the public Internet.
The trunk network can already run out of capacity - you do not now have dedicated bandwitdth and never had dedicated bandwidth over the trunk network (ever got the 'All circuits are busy' message?) A packet based trunk network is no less secure than the existing trunk networks. Packet switching != routing over the public internet.
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Part of what you are describing is called virtual circuit switching in which a 'circuit' is established over a packet switched network. In real circuit switching there is a dedicated electrical circuit between the two endpoints, which indeed can be both digital and analogue.
TDM is sort of a strange thing in that there is no real electrical circuit but you do get a dedicated time slot on the line. ATM definitly is packet switched.
Guaranteeing bandwith (QoS) is not hard at all, the routers simply need a table of active circuits.
Only packets for those circuits and in only a certain amount get through.
Jeroen
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I presume the insertion of "IP" in the title of this article was a mistake or assumption made by a naeive author? You don't use IP to carry telephone calls on a phone network. Ever. IP is no good for carrying voice data and there are many better protocols around which were designed for this purpose. I presume that they really mean ATM or some other voice protocol? You need a small packet, circuit based protocol to handle large numbers of voice calls efficiently. Although IP could be made to work, it would be pretty difficult and is essentially rather like trying to put a sealed bus in a sea to try and make a ferry - why not just use a boat?
Nick...
The really fun thing about this means that any router can be told to simply copy every packet in a particular conversation to law enforcement.
Add to this that a traditional switched network gets really noise after a few switches and digital networks will....
This kind of switching hasn't been done for years. Electronic phone exchanges have existed for decades, and digital phone exchanges (at least where I live) have made up the entire network for over 10 years.
The electromechanical exchanges did manage to hang on into the early 1990s in many places though. Good old Strowger. (An excellent site about the phone network in days gone by is Light Straw. If you are ever in a position to visit the London Science Museum, they have a good-sized portion of a Strowger phone exchange that you can play with - makes lovely clattering noises!)
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Although they will probably use IP to transport voice data between their switches, that does not mean that any of the data will travel over the public Internet or that the end users will use IP. All this does is change the design of the subnet used to transport voice data in between toll switches, not the interface between the toll switch and the end user.
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Consumer benifits....
1. One phone number for multi devices (I think this was covered in the article).
2. Phone numbers not tied to physical location, but rather device or authentication. Would be most nifty for mobiles to go landline. (this was covered)
3. Multi communication... end users could in theory have two telephones, and place two calls on the same line. No further need for an alarm wire from your telco.
4. No D/A loss when you copy your CD over your phone.
5. Everyone is highspeed internet ready... in theory you need 32Kbit for decent voice, perhaps 64K / 128K bit just to be safe. Pay more money to throttle you up to internet speeds... no more waiting for low paid installers.
6. Networked appliances no longer need "internet access" but rather phone access, and no gay ass 300 baud modems in your digital cable box.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
British Telecom's main fibre optic backbone is a packet-switched network. It's only the "last mile" that's truly circuit switched these days. We have a fairly modern telephone system in the UK, only hampered by stupid area codes based on centres of population rather than numbers of people as in the US (so the big towns such as London, Bristol, Reading and Leicester ran out of numbers quickly and had to have their codes changed). To be fair, no-one anticipated fax machines and data connections when the coding system was decided.
When I am king, you will be first against the wall.
The Sprint Press Release states that they are going to use ATM, not IP.
RFC1925
1. This is only going to help drive down cell phone prices, helping to make land lines obsolete once again. (This was likely to happen eventually anyway, right?) If the article is right and you can forward your conversations to any IP address (at an extra cost), the primary advantage cells have are mobility, such is the case now. Until, that is, when you think about wireless solutions and VoIP. Mmmmm...DHCP + VoIP :)
2. A brief search of the web suggests VoIP can be more secure than traditional telephony. To what extent will government fight this? Effectively having an SSH tunnel to the other caller wouldn't be appreciated by the gov't given the present modus operandi of the US.
3. VoIP is certainly a logical progression, and I don't see the big telcos going out of business soon. Where I live, there are just a few DSL providers but only one company (SBC) owns all the wires into the area. Their only real competitor is cable TV whom they are fighting tooth and nail to gain marketshare. I imagine access to wireless frequencies has very little competition (think: 802.11), but will there need to be legislation to keeping it open?
To-do List: Receive telemarketing call during a tornado warning. Check.
I have been installing VOIP, VOFR, and IP Telephony for years now for many businesses, I have lots of 99.999% uptime systems, no complaints in almost two years for quality of voice, I can't believe /.ers are amazed and puzzled by such simple things as a forty year old idea being used by a carrier. I guess /. isn't what it used to be.
Somebody needs to read up on how DNS works. Domain names are resolved from back to front.
Very simple. It doesn't get mixed in. These networks are (ofcourse) private and the traffic on it are controlled. Meaning yoo don't get access to it unless you dig up the fibre yourself and use fibre splitters on them.
Perhaps in the US....
I was working as a Network Engineer for them, in amsterdam, and as far as I know, we only had a test IPv6 network.
We did a lot of discussing IPv6, and as per most of the big ISPs right now, decided that it isn't currently worth it.
Could insert obligatory US != world comment, but to be honest that's totally how Wcom worked....Europe? that in Texas ???
tom-george.comBecause geeks rate higher t
No, this isn't Sprint's long distance network. It is Sprint LTD (local telecommunications division). It also doesn't mean that any bug clogging the web will bring down service - this is not voice over the Internet. In fact, it is not even voice over IP. It's voice over ATM.
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So, I'm a very recent ex-nortel person who did a lot of packet stuff. If I recall correctly, Sprint's network is an ATM one, either AAL1 or AAL2. AAL5 is IP-over-ATM, and isn't as common.
Note that in general, these are all behind-the-scenes private networks. You will still be circuit-switched to a point (inside your local office, typically). Then there'll be a TDM-to-packet gateway which converts your circuit-switched connection into ATM (or IP).
From an IP point of view, one of the side effects of this is that you don't need a seperate IP address for every phone, or even a seperate address for every house. All you need is an IP address/port number combination for each end of an active call in any given network. (And there are ways of getting around that restriction too.) Since these are all private networks cut off from the internet, IPV4 provides more than enough addresses.
Packet telephony all the way to the home, at least from the telcos, is some ways off. You'd either have to have a gateway inside your house to which you connect all your legacy phones, or you'd replace all the phones with IP phones. As you can probably see, there's a lot of inertia behind that *not* happening -- try convincing your great uncle Bert that he needs to replace all the phones in his house.
That is not an excuse, it is simply the truth. *DSL needs a pair of metal wires. If you do not have that, no *DSL for you. You may have to make do with STM4. The US equivalent of STM4 is OC12, by the way.
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See Nortel UEMG9000 for info.
I used to work on this, and can say that its quite a robust system. Runs about 8000 POTS lines or 2000 xDSL, and also supports DS1 and TDM lines. Backbone is OC3 ATM with other options available. VOIP should be done now/soon but I don't believe Sprint went that route. The system has Echo Cancellation and all the other required perks to ensure good quality.
Used to.. Anyone need an embedded driver dev in RTP?
check out vonage. www.vonage.com they provide a box that plugs into your network, and has an rj-11 phone jack. really, really cool service, and it's cheap and good. Take the vonage box anywhere, plug it in, and your standard $10 telephone rings there as if it's local.
it's cool stuff. a friend of mine is using it and I'm signing up next week.