Signaling System for Telecommunications

Abstract

A pair of devices ( 400, 401 ) appear to be a Common Channel Signaling (CCS) network nodes on each end of a pointdigital data link, that is, a normal CCS signaling link ( 402, 403 ). Multiple transport methods may be used to provide a redundant and diverse path for the signaling link. These methods include the encapsulation of the CCS protocol, at one or more layers, within other network protocols. In another embodiment, the present invention implements a virtual Signal Transfer Point by means of one or more encapsulating STPs (eSTPs). A packet data network ( 408 ) using standard packetdata protocols, rather than a backplane bus or specialnetwork, connects the encapsulating STPs ( 405, 406 ), and CCS messages are dynamically routed across the internal packet data network to an appropriate eSTP for transmission to the appropriate next hop address. The entire group of eSTPs appears to be one STP to the CCS network, but on the internal packet data network each eSTP operates as an autonomous message router for CCS traffic.

1 . A method for use with a data communications system comprising first and second apparatus, each of said first and second apparatus having a respective port disposed for sending and receiving common channel signaling data for telephone call processing, the first and second apparatus connected by a packet-switched communications channel, said channel of a type routing messages over an arbitrary path comprising hops including a final hop, said channel of a type in which the final hop of a path is not fully known in advance; the method performed within each apparatus comprising the steps of:
 receiving common channel signaling data via the respective port,   stripping flag octet and cyclic redundancy check bits therefrom before encapsulation;   encapsulating said common channel signaling data in packets, and   transmitting said packets to said packet-switched communications channel; said method performed within each apparatus further comprising the steps of:   receiving said packets from said packet-switched communications channel,   extracting said common channel signaling data from said packets, and   transmitting said common channel signaling data via the respective port.   
     
     
         2 . The method of  claim 1  wherein the first and second apparatus are further connected by an oncommunications channel; said method further comprising the steps of testing the packet-switched communications channel, responding to a failed test of the packet-switched communications channel by establishing the on-demand communications channel; receiving common channel signaling data via the respective port of the first and second apparatus and transmitting said encapsulated packets to said on-demand communications channel; receiving said packets from said on-demand communications channel and extracting said common channel signaling data from said packets, and transmitting said common channel signaling data via the respective ports of said first and second apparatus. 
     
     
         3 . A data communications system comprising first and second apparatus at distant physical locations, said first and second apparatus communicatively coupled through a wide-area network having a wide-area-network message protocol;
 each of said first and second apparatus comprising a port sending and receiving common channel signaling messages, each of said first and second apparatus further comprising means for encapsulating said common channel signaling messages within messages conforming to said wide-area-network protocol, and means for unencapsulating said common channel signaling messages from within messages received from said wide-area network;   each of said first and second apparatus further comprising a routing table defining destinations for said common channel signaling messages depending on the contents thereof, and computational means routing common channel signaling messages among said first and second apparatus as determined by said routing table;   each of said first and second apparatus further comprising means responsive to received messages for updating the respective routing table.   
     
     
         4 . The system of  claim 3  wherein each of said first and second apparatus further comprises cryptographic means encrypting messages communicated to said wide-area network and decrypting messages communicated from said wide-area network. 
     
     
         5 . The system of  claim 3  wherein each said port sending and receiving common channel signaling messages is a synchronous port, and wherein said wide-area network is a packet switched network. 
     
     
         6 . The system of  claim 5  wherein said wide-area network is an internet. 
     
     
         7 . A method for use with a data communications system comprising first and second apparatus at distant physical locations, said first and second apparatus communicatively coupled through a wide-area network having a wide-area-network message protocol; each of said first and second apparatus comprising first and second ports sending and receiving common channel signaling messages, each of said first and second apparatus further comprising a routing table defining destinations for said common channel signaling messages depending on the contents thereof; said method comprising the steps of:
 receiving an update message via said wide-area network and updating said routing table in response thereto;   receiving a first common channel signaling message at said first apparatus at its first port;   selecting said second port responsive to said routing table and responsive to contents of said first message;   transmitting said first message at said second port.   
     
     
         8 . A method for use with a data communications system comprising first and second apparatus at distant physical locations, said first and second apparatus communicatively coupled through a wide-area network having a wide-area-network message protocol; each of said first and second apparatus comprising a respective port sending and receiving common channel signaling messages, each of said first and second apparatus further comprising a routing table defining destinations for said common channel signaling messages depending on the contents thereof; said method comprising the steps of:
 receiving an update message via said wide-area network and updating said routing table in response thereto;   receiving a first common channel signaling message at said first apparatus at its respective port;   selecting said wide-area network responsive to said respective routing table and responsive to contents of said first message;   encapsulating said first message in a second message of said wide-area-network message protocol; and   transmitting said first message to said wide-area network.   
     
     
         9 . The method of  claim 8  further comprising the steps of:
 receiving said second message at said second apparatus from said wide-area network;   unencapsulating a third message from said second message;   selecting the respective port of said second apparatus responsive to said respective routing table and responsive to contents of said third message; and   transmitting said third message to said port of said second apparatus.