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?"

Comments

Re:Not IP

[hughk]

Modern switches can talk IP. They are essentially just computers with some specialised I/O. Switches can talk to each other locally via a LAN and they can send long distance traffic via a variety of WAN connections. IP6 has been preferred for a while between switching centres because of the QoS support. The lower layer is generally ATM.

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.

Re:IP?

[pe1rxq]

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

Re:But will this benefit the consumer ?

[zakezuke]

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.

Re:Not IP

[cfulmer]

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.