Telephonic communications – Plural exchange network or interconnection – With interexchange network routing
Reexamination Certificate
1996-11-21
2001-01-09
Matar, Ahmad F. (Department: 2742)
Telephonic communications
Plural exchange network or interconnection
With interexchange network routing
C379S260000, C379S221050
Reexamination Certificate
active
06173051
ABSTRACT:
TECHNICAL FIELD
This invention relates to the implementation of customized routing in the interconnection of public switched telecommunications networks and more particularly relates to the provision of such routing for both unbundled switching and resale.
ACRONYMS
The written description uses a large number of acronyms to refer to various services, messages and system components. Although generally known, use of several of these acronyms is not strictly standardized in the art. For purposes of this discussion, acronyms therefore will be defined as follows:
Action Control Point (ACP)
Advanced Intelligent Network (AIN)
Area Code (NPA)
Automated Message Accounting (AMA)
Automated Number Identification (ANI)
Central Office (CO)
Competing Local Exchange Carrier (CLEC)
Common Channel Signaling (CCS)
Dual Tone Multifrequency (DTMF)
End Office (EO)
Handoff Switch (HSW)
Integrated Services Digital Network (ISDN)
Integrated Service Control Point (ISCP)
Intelligent Network (IN)
Interexchange Carrier (IXC)
Line Class Codes (LCCs)
Local Access and Transport Area (LATA)
Local Exchange Carrier (LEC)
Off-Hook Delay (OHD)
Office Code (OC or NXX)
Operator Services Position System (OSPS)
Operator Services Signaling (OSS)
Originating Switch (OSW)
Primary Interexchange Carrier (PIC)
Point in Routing (PIR)
Point of Presence (POP)
Private Branch Exchange (PBX)
Service Creation Environment (SCE)
Service Control Point (SCP)
Service Switching Point (SSP)
Signal Switching Point (SSP)
Signal Transfer Point (STP)
Signal Control Point (SCP)
Signaling Point (SP)
Signaling System
7
(SS
7
)
Signaling Switching Point (SSP)
Signaling Transfer Point (STP)
Traffic Operator Position System (TOPS)
Traffic Service Position System (TSPS)
Transaction Capabilities Applications Part (TCAP)
BACKGROUND OF THE INVENTION
Recent legislative and regulatory changes require that a local exchange carrier (LEC) unbundle certain network elements and services and offer use of those elements and services to other carriers for resale to end users. In one required implementation the LEC will sell the other carrier an unbundled port on an end office switch and allow the other carrier to become a competing local exchange carrier (CLEC) by reselling services of the switch to end users having local loops which connect to the end office switch. Those statutory and regulatory changes also specify that customized routing is required for both unbundled switching and for resale. Customized routing is the term used in the regulations for routing calls made in the local exchange carrier (LEC) switch to locations other than those that exist today. The primary applications are for unbundlers and resellers to have operator (0+, 0−) calls and directory assistance calls (411/555) routed to their own platforms. Other types of calls could possibly be applicable as well, but the 0+/0−/411 calls are the ones in most immediate demand.
This type of customized routing in an interconnection environment represents a capability that currently does not exist in the network architecture of LECs. The currently used switches in the LEC public switched telephone networks were not designed with this functionality in mind. The capability does not exist and the switches are not readily adaptable to provide customized routing. This applies to all of the predominantly deployed switches (5ESS, 1AESS, EWSD, and DMS-100) from three major switch manufacturers, Lucent Technologies (formerly AT&T), Nortel, and Siemens.
One prospective unbundler and reseller has suggested use of line class codes (LCCs) to accomplish this purpose. However, any implementation of customized routing using LCCs would require use of an excessive number of such codes and would produce other serious problems. Not only is there a limit to the capacity of the switch regarding the number of LCCs that could be physically provisioned, managing the new operational environment is at least as critical. The provisioning and maintenance systems that support the LEC's services cannot be ignored. These systems allow telephone services to be ordered, provisioned, monitored, repaired, and billed; they are an essential element in contributing to the quality of service enjoyed today by the public LEC's customers.
Without incorporating new LCCs into the operations systems that support services, severe problems would have to be expected in provisioning services. Manual provisioning would require human intervention and complex lookups that involve locating the correct code in a table of thousands. Such a process would be prone to both error and delay resulting in service degradation. It is for this reason that today's process is mechanized. In an environment with considerably more codes, a mechanized process would be even more important.
The line class code approach would use existing switch resources in a manner that was never intended. Such an application is untested and to some degree would have unknown consequences if deployed on any meaningful scale. Even the proponent of this approach has indicated that LCCs would be an interim and limited workaround which would need to be reversed once a longer term solution could be developed.
Another proposal for coping with the problem has been the possible use of an Advanced Intelligent Network (AIN) common channel signaling (CCS) solution. However, this is not feasible in view of the fact that, while the AT&T 1AESS switch has AIN capability, it will not apply AIN type processing to 0 calls. In that switch, the 0 number routing functionality takes precedence over all other types of call processing, including AIN processing.
The patent literature suggests various approaches to more or less analogous problems.
U.S. Pat. No. 5,550,912, issued Aug. 27, 1996 to Akinpelu et al., and U.S. Pat. No. 5,475,749, issued Dec. 12, 1995 to Akinpelu et al., assigned to AT&T Corporation, disclose specialized call processing in an interexchange carrier (IXC) network to route calls via a LEC and a CLEC or competing local exchange carrier (termed a ‘competing access provider’ or ‘CAP’ in these patents).
In one aspect of the Akinpelu et al. call processing, the switch of the IXC network serving as the egress point for a call, checks the area code (NPA) and office code (OC or NXX) of the dialed number to determine if ‘exception’ routing is necessary, i.e., to determine if the destination station lies in a region served by a LEC and one or more CLECs. If no exception routing is necessary (LEC only), the egress switch routes the call through the LEC carrier switch in the normal manner. However, if exception routing is necessary, the egress switch checks the last four digits of the called number against an exception table to determine if the particular number is served through a CLEC switch or a LEC switch. The table look up can utilize translation tables in the egress switch or tables in a remote database. If the last four digits from the dialed number are listed in the exception table, then the egress switch routes the call through the CLEC's switch. If the last four digits from the dialed number are not listed in the exception table, then the egress switch routes the call through the LEC's switch. If the called customer receives service from both a CLEC and a LEC, the egress switch will route the call through the CLEC switch unless all trunks between the IXC egress switch and the CLEC switch are busy, in which case the egress switch routes the call via the LEC switch.
The Akinpelu et al. Patents also disclose a specialized translation and routing process at the ingress switch of the IXC network. In some cases, a different egress switch serves a CLEC than serves a LEC. For such a case, the ingress switch queries a database. The database identifies the called customer's preferred local exchange carrier and possibly an alternate carrier. Based on the local carrier identification (LEC or CLEC), the ingress switch routes the call through the appropriate egress switch. Data identifying the IXC egress switch, the preferred and alternate carriers and
Florindi Robert P.
Lipchock Michael J.
Bell Atlantic Network Services Inc.
Matar Ahmad F.
McDermott & Will & Emery
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