Telephonic communications – Plural exchange network or interconnection – With interexchange network routing
Reexamination Certificate
2000-03-28
2003-09-23
Matar, Ahmad F. (Department: 2642)
Telephonic communications
Plural exchange network or interconnection
With interexchange network routing
C379S221110
Reexamination Certificate
active
06625273
ABSTRACT:
RELATED PATENT APPLICATIONS
This application relates to the following co-pending United States Patent Application, incorporates them by reference in their entirety and is assigned to the assignee of the present invention:
Ser. No.:
Filing Date:
Inventors:
Title:
09/536,541
Mar. 28, 2000
Ashdown et al.
Intelligent
Communications
Point Platform
09/536,598
Mar. 28, 2000
Ashdown et al.
New and Improved
System and Method for
Data Traffic Redirection
09/391,295
Sept. 7, 1999
Ashdown et al.
SS7 Firewall System
BACKGROUND
The invention is related to the Common Channel Signaling System No. 7 (SS7) technology employed in the public switched telephone network (PSTN). The SS7 network is the backbone of the world's telecommunications networks. SS7 is a protocol developed by international standards organizations to efficiently manage call initiation, management, and termination, wireless services, including personal communications services (PCS), wireless roaming, and mobile subscriber authentication, local number portability (LNP), toll-free numbers and toll numbers (800 and 900 numbers), and a variety of other call features.
Communication on an SS7 network falls into two distinct categories: command and control signals and network traffic. General voice traffic is carried in-band on voice channels. The command and control signals are carried out-of-band and are used to manage the network traffic. The points on the network are divided into three classifications: Service Switching Points (SSP), Signal Transfer Points (STP), and Service Control Points (SCP).
At the most fundamental level, voice calls are transmitted from the user's handset to the originating SSP, to the destination SSP, and finally to the call recipient. Voice traffic is carried on large, multi-path trunk lines. The routing of SS7 traffic is managed by the STPs. (For simplicity, in the following example it is assumed that a call originates with one SSP and terminates with the destination SSP. In reality, a call may be routed through numerous SSPs before it reaches its destination.)
When a call is initiated, the SSP sends a message to the appropriate destination SSP. The STP routes the messages to the destination SSP. The originating SSP then designates which path in the trunk line between the two SSPs will carry the call, and notifies the destination SSP to establish the connection. When one of the parties hangs up, a call termination signal is generated by one SSP and relayed to the other.
Toll-free (800) calls, calling-card calls, wireless calls, and other such calls require the exchange of additional, non-circuit data between SSPs. Unlike standard calls that require no additional data in order to be routed by the STPs, these non-standard calls require additional information. The Transactions Capabilities Applications Part (TCAP) functionality defined in the SS7 protocol is used to obtain the additional routing information required to complete these calls. TCAP messages carry a variety of queries and responses between SSPs and SCPs.
For example, to facilitate toll-free (800) calls, the SSP performs a lookup to route the call. An 800 number is actually an alias for a standard telephone number. When a call is made to a toll-free number, the SSP must determine what standard telephone number the alias (800 number) represents. To do this, the SSP generates a TCAP query that is transmitted to an SCP. The SCP maintains a large database correlating the aliases with the standard phone numbers. The SCP looks up the correct number in the database and relays the number back to the SSP. The SSP then completes the call via the standard process.
Local Number Portability (LNP) lets subscribers keep their phone numbers after changing service providers or relocating. LNP is vital to the successful introduction of local telephone competition. LNP employs the same mechanism as toll-free numbers. To facilitate LNP, additional SCPs are established to allow LNP alias lookups.
As the entire telecommunications industry expands, the demand for LNP and other TCAP-related capabilities will escalate. SCPs are owned and operated by large telecommunications companies (typically Regional Bell Operating Companies or service bureaus) who charge a fee for each query. For small to mid-sized telecommunications companies, this expense will increase with any expansion. The only way these companies can presently eliminate this expense is to create their own SCP. The technical and economic barriers to creating SCPs are prohibitive for most of these companies.
As these TCAP-related calls become an increasing percentage of a company's traffic, it will become more and more important to manage the associated costs. Currently, the smaller telecom companies have no independent means for monitoring these costs. With no visibility of the TCAP traffic, they are solely dependent on the reporting mechanisms of the SCP for TCAP traffic statistics. The only current methods for implementing this visibility are designed for STPs, not SSPs. These methods are cost-prohibitive for smaller operators.
This increasing demand will cause another problem with the SS7 network in general. As LNP becomes commonplace, there will be a corresponding increase in the number of TCAP messages carried on the SS7 network. Therefore, what is needed is a means to minimize the number of queries made to the SCPs by the SSPs.
SUMMARY OF THE INVENTION
The present invention, accordingly, provides a system and method for minimizing the reliance upon SCPs for call routing data. The system, which is installed between the service providers' SSP and the network, acts as a local cache, storing the results of SCP queries. When subsequent requests for the same lookup is received, rather than being passed on to the SCP (and incurring a charge) the query is intercepted, a look-up is performed, and the locally stored number is sent back to the SSP. The SSP then has the information necessary to complete the call. By using the locally stored query result, the company avoids paying multiple fees for the same lookup. Query results are stored in the local cache with a defined expiration time. After the result expires from the cache, the subsequent request for the lookup will be executed in the standard fashion, retrieving the information from the SCP and repopulating the local cache.
The present invention is enabled by the Intelligent Communications Platform (ICP). Although the ICP is described in greater detail in the incorporated by reference patent application listed above entitled “Intelligent Communications Platform”, a short summary will now be described. The ICP is located on the network between the SSP and the STP. It has no point code, and is therefore totally transparent to the SS7 network. The ICP intercepts all TCAP information into and out of the SSP. It is designed for fail-safe pass through of all SS7 information. In the event of an ICP fault SS7 traffic passes through unimpeded.
The ICP provides a platform for a variety of applications that monitor and manipulate this TCAP data. The ICP includes a TCP/IP connection to an Intelligent Communications System (ICS). The ICS is used to configure and manage these applications. In summary, the ICP adds additional intelligence and functionality to the customer's SSP at a reasonable cost.
A LNP cache (LNPC) application runs on the ICP, monitoring LNP queries. It incorporates a high-speed database where the results of queries are stored along with a time stamp. When a query is intercepted, the LNPC performs a database lookup. If the requested information is found, the LNPC sends the result back to the SSP, eliminating the SCP lookup. If the query does not yield a result, the LNPC maintains an active thread waiting on the response from the SCP. When the response is received it is stored in the database with a time stamp and relayed back to the SSP to complete the call. To maximize performance a caching algorithm is employed. In addition, configuration of the LNPC is accomplished via the ICS.
A primary technical advantage of the invention is
Ashdown Mike
Henderson Dave S.
Shen Hu
Agdeppa Hector
Haynes and Boone, LLP.
Matar Ahmad F.
Sevis Systems, Inc.
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