Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1999-11-16
2003-09-09
Hsu, Alpus H. (Department: 2665)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C379S088170, C709S203000
Reexamination Certificate
active
06618370
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates generally to telecommunications systems. More particularly, the present invention relates to an advanced intelligent network system for providing flexible bandwidth to an Internet Service Provider commensurate with the demands for dial-up access to the Internet Service Provider's resources.
2. Background of the Invention
Over the last ten years, use of the Internet has grown rapidly. A large segment of this growth stems from an increase in individual dial-up subscribers. These dial-up subscribers use the public switched telephone network (“PSTN”) to establish connections to their Internet Service Providers (“ISPs”).
FIG. 1
is a schematic diagram illustrating how these dial-up subscribers, or users, connect to their ISPs using PSTN
10
. To support multiple connections, ISPs must maintain numerous telephone lines connected to modems. Rather than advertising a different telephone number for each telephone line, ISPs generally advertise a limited number of telephone access numbers. Each telephone access number corresponds to one or more telephone lines. These telephone lines may be made up of, e.g., individual POTS lines, one or more T
1
lines, or Primary Rate Integrated Services Digital Network (“PRI”) lines. For simplicity, the figures and discussion herein show the connections to be made up of PRI lines.
As shown in
FIG. 1
, ISP
20
may provide multiple telephone access numbers, each corresponding to PRI lines connected to multi-line hunt groups (“MLHGs”). MLHGs are modem pools allowing multiple simultaneous connections to the ISP via a single telephone access number. A multi-line hunt group takes incoming subscriber calls and routes them to the first open modem in the modem pool.
FIG. 1
shows four sets of PRI lines
26
-
29
connected to four MLHGs
22
a
-
22
d
, respectively. The MLHGs are controlled by access server
23
. When caller
30
dials one of ISP
20
's telephone access numbers (using computer
31
, modem
32
and subscriber line
33
), PSTN
10
processes the call like any other call. That is, the call is routed between caller
30
and the called party (in this case, ISP
20
) through one or more service switching points (“SSPs” or “switches”). If the lines corresponding to the dialed telephone access number are all busy, or “off-hook”, i.e., there are no voice communications paths available, the caller gets a busy signal, which is provided by PSTN
10
.
If lines are available, the ISP's switch, SSP
12
in
FIG. 1
, terminates the call. Access server
23
answers the call and determines whether or not the caller is a valid ISP subscriber. If the caller is valid, then access server
23
must determine which services the caller should have access to. Access server
23
queries caller
30
for information such as a username and password for use in validating caller
30
and determining caller
30
's authorized services. The dialog between caller
30
and access server
23
is usually performed automatically between access server
23
and communications software operating on computer
31
.
Generally, ISPs use centralized servers to store and manage their subscriber databases. Remote Authentication Dial-In User Service (“RADIUS”) server
24
, having database
24
a
, is functionally connected to access server
23
and provides this centralized management. Thus, access server
23
collects username and password information from caller
30
and passes it on to RADIUS server
24
. After RADIUS server
24
verifies caller
30
's username and password, it provides access server
23
with configuration information specific to caller
30
. Access server
23
uses the configuration information to provide the authorized services to caller
30
. Access servers and RADIUS servers are described in more detail in commonly assigned U.S. patent application, Ser. No. 09/133,299, which is incorporated herein by reference in its entirety. Additional information on access servers and RADIUS servers may be found in Rigney et al.,
Remote Authentication Dial
-
In User Service
(
RADIUS
), Network Working Group, January, 1997, or in Rigney et al.,
RADIUS Accounting
, Network Working Group, April, 1997.
An ISP incurs great costs for purchasing and maintaining the telecommunications infrastructure needed to operate its business. The ISP must pay its local telephone service provider (“telco”) for each telephone line maintained. Additionally, the ISP must purchase and maintain MLHGs and the associated modems for the groups. Finally, the ISP must manage and balance the load on each of its MLHGs in order to provide efficient connections for its subscribers. Due to the high cost of purchasing and maintaining the infrastructure, it is desirable for an ISP to provide only as many lines and modems as are required to accommodate its subscribers' demand.
It is well known in the art that not all subscribers connect to their ISPs at the same time. Additionally, not all subscribers connect every day, nor do they connect for the same length of time each session. For this reason, it is not cost-effective for ISPs to provide a 1:1 ratio of lines to subscribers. Instead, ISPs have developed formulas to determine the appropriate number of telephone lines required. In general, a telephone line to user ratio of at least 1:10 provides an acceptable level of service. However, as Internet usage continues to grow, it is becoming more difficult to predict the requirements for telephone lines into an ISP. Thus, a need exists for a system and method to balance the competing interests of reducing ISP costs and providing acceptable levels of service for ISP subscribers. A further need exists for a system and method providing ISPs with flexible access to increased telephone lines and modems, i.e., increased bandwidth, as the need arises to support the ISPs' customers. A system and method is needed to provide such flexible bandwidth on demand for ISP's without significantly increasing the complexity or costs for ISP operations.
SUMMARY OF THE INVENTION
The present invention provides a system and method allowing ISPs to dynamically expand the number of telephone lines and modems available to ISP subscribers dialing into ISP systems. The present invention utilizes an Advanced Intelligent Network (“AIN”) to provide an automated system and method for providing this flexible bandwidth to ISPs. AIN systems are described in U.S. Pat. No. 5,701,301, U.S. Pat. No. 5,774,533 and Bellcore Specification TR-NWT-001284, Switching Systems Generic Requirements for AIN 0.1, which are incorporated herein by reference in their entirety.
FIG. 2
shows the important components of the AIN used in the present invention. The steps described herein can be performed by computer-readable program code operating on the various AIN components and other computer systems, as described below.
In a preferred embodiment of the present invention, an AIN automatic flexible route (“AFR”) trigger is provisioned on the trunk group in SSP
212
providing PRI lines
226
into ISP
220
. The PRI lines are connected to MLHG
222
at the ISP, which is reached by dialing the corresponding telephone access number. The trigger is activated when a subscriber dials the telephone access number and there are no open lines available. In response to the trigger, a database query goes from SSP
212
to service control point (“SCP”)
215
via ss
7
network
213
. SCP
215
writes the contents of the called party number (“CdPN”) field, i.e., the dialed ISP telephone access number, into the calling party number (“CgPN”) field and specifies a new location to forward the call with instructions to monitor the call for termination status. The call is thus forwarded to the telco's shared modem pool, MLHG
219
, without losing the ISP telephone access number dialed by the subscriber. In this manner, the telco's proxy RADIUS server
217
can determine which ISP the call will be directed to.
Acting on the instructions from SCP
215
, SSP
212
forwards the call s
BellSouth Intellectual Property Corporation
Hsu Alpus H.
Nguyen Toan
Shaw Pittman LLP
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