Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1998-04-21
2003-07-22
Kizou, Hassan (Department: 2662)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S401000, C370S252000
Reexamination Certificate
active
06597686
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to routing calls in a telephone network, and more particularly to methods and apparatus for routing calls in a network including the Internet.
Internet telephony is two way voice communication over a packet switched network, such as the Internet.
FIG. 1
is a diagram of an Internet voice communication network including Internet telephony equipped computers
102
and
110
, Internet Service Providers
104
and
108
, and the Internet
106
. To establish voice communication over the Internet using currently available Internet technology, each participant in a voice call must have a computer equipped for Internet access and special hardware and software supporting Internet voice communication. For example, computers
102
and
110
would require a modem, TCP/IP software, a dialer, a sound card, a microphone, and a speaker to be suitably configured for Internet telephony.
To obtain Internet telephony service using an Internet telephony equipped computer, the parties to a call, computers
102
and
110
connect to an Internet Service Provider providing access to Internet
106
. Accordingly, Internet Service Provider account holders paying a flat fee for Internet access can engage in voice communication with one another over the Internet without incremental usage charges. Although the advantage of voice communication using Internet telephony according to current billing methods is the insensitivity of the cost of calls to their duration, there are several drawbacks to this approach. First, each party to Internet telephony voice communication must have a computer and it must be properly equipped for voice communication. Second, computer
110
must be connected to Internet
106
at the time computer
102
initiates a call. Third, many of the Internet telephony software packages are not compatible with other vendors' Internet telephony software. Fourth, the sound quality of Internet telephony calls is generally worse than the sound quality of calls transmitted through the public switched telephone network (PSTN).
To address some of the limitations of providing voice communication through the Internet imposed by using the Internet and telephony-capable computer terminals, some vendors have developed Internet telephony gateways. Internet telephony gateways allow parties that only subscribe to “plain old telephone service” (POTS), but do not have Internet equipped computers and an account with an Internet service provider, to talk to each other through the Internet.
FIG. 2
is a network diagram of an Internet telephony service for POTS subscribers. The network of
FIG. 2
includes telephone
202
, PSTN
204
, Internet telephony gateway
206
, Internet
214
, Internet telephony gateway
216
, PSTN
224
, and telephone
226
.
Internet telephony gateway
206
includes gateway controller (GC)
208
, voice translation unit (VTU)
210
, and interactive voice response unit (IVR)
212
. Internet telephony gateway
216
is similarly configured with GC
218
, VTU
220
, and IVR
222
. A GC performs signaling required for call setup and call tear down between a PSTN and the Internet; accordingly a GC supports both PSTN and Internet signaling protocols. A VTU processes voice signals, which includes packetizing and depacketizing the voice data stream between the PSTN and the Internet. An IVR plays announcements to a calling or called party and collects digits entered using a telephone touch-tone (dual tone multi-frequency (DTMF)) key pad.
To establish an Internet telephony call through the Internet telephony gateway network depicted in
FIG. 2
, a phone call originator dials from telephone
202
a telephone number assigned to Internet telephony gateway
206
serving PSTN
204
. Internet telephony gateway
206
answers the call and connects the caller to IVR
212
. Internet telephony gateway
206
interacts with the caller using IVR
212
by playing announcements and collecting digits entered by the caller. Examples of information collected from the caller by IVR
212
include the telephone number of called party at telephone
226
, the caller's user identification number, and password. By analyzing the called party's telephone number, Internet telephony gateway
206
determines the network address of Internet telephony gateway
216
, which is the Internet telephony gateway providing the least cost path to the called party at telephone
226
. Internet telephony gateway
206
then sends a call setup signaling request to Internet telephony gateway
216
using GC
208
. Responding to the call setup request, Internet telephony gateway
216
rings telephone
226
. When the called party answers telephone
226
, an end-to-end communication path is established through the network between telephone
202
and telephone
226
. This path includes three segments, a circuit switched path between telephone
202
and PSTN
204
, a packet exchange through Internet
214
between Internet telephony gateway
206
and Internet telephony gateway
216
, and a circuit switched path between telephone
226
and PSTN
224
.
An advantage of using Internet telephony gateways to provide voice communication over the Internet is that such a service is integrated with the calling and called parties' regular telephone service. Neither party requires special computer equipment or an Internet service provider account. Moreover, for one party to place an Internet voice call through the Internet using Internet telephony gateways, both the calling and called party do not have to be logged onto the Internet.
FIG. 3
is a diagram of networks for providing telephone service. Using Internet telephony gateways, telephone service carriers are beginning to offer service that allows callers a choice of voice communication through a circuit switched telephone network
312
, an Internet-based packet voice network
314
, or through a hybrid network including both a circuit switched telephone network and an Internet-based packet voice network
316
. Points of presence (POP)
306
,
308
,
310
,
326
,
328
, and
330
deployed throughout local PSTN
304
and local PSTN
332
provide access to these networks. Points of presence providing voice communication service through the Internet, i.e., POPs
308
,
310
,
328
, and
330
, contain Internet telephony gateways as described in greater detail above.
Because of the cost/performance trade-offs associated with choosing Internet-based voice communication versus circuit switched voice communication, telephone service subscribers want the ability to choose on a call-by-call basis the method of transmission of a voice call. For example, when quality of service is an overriding concern for a given call, the calling party will most likely want the call completed through a circuit switched network. When, on the other hand, price is an overriding factor, the calling party would select an Internet-based telephone service provider. Not only should a caller be able to select between Internet service and circuit switched service, but a caller should also be able to choose among several Internet-based voice communication service providers having different rate structures and having POPs closest to the called party.
Accordingly, it is an object of the invention to provide an Internet telephony routing capability that allows intelligent routing of telephone calls through Internet-based voice communication service providers when such routing conforms with caller preferences.
As previously described, the current state of the art in Internet telephony requires a phone call originator to dial a telephone number associated with the Internet Telephony gateway and subsequently interact with the gateway to enter the caller's account number and identification number, as well as, the called party's telephone number. This dialing procedure corresponds to the dialing procedure used for making PSTN phone calls using calling cards or debit cards. It is also an object of the invention to provide Internet Telephony users with the ease of use tha
Falk James W.
Giordano Joseph
Kizou Hassan
Pezzlo John
Telcordia Technologies Inc.
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