Patent Grant
7113581
The present invention relates to the routing of signaling messages in a converged telephony-data networking environment, and more particularly to the automatic registration of routing key information at a gateway routing node.
The convergence of traditional telecommunication networks and traditional data networks has given rise to a number of challenging connectivity issues. Such connectivity issues are particularly significant in the realm of call control signaling. More specifically, traditional public switched telephone network (PSTN) call control signaling is performed via a signaling system 7 (SS7) signaling protocol, while signaling within a data network is typically performed by any of a number of signaling protocols including: transport adapter layer interface (TALI), session initiation protocol (SIP), session description protocol (SDP), H.323, M2UA, M3UA, SUA, etc. In a converged communication network environment, such call control signaling protocols are employed to provide a variety of converged or inter-network services. These services include providing basic call setup and teardown functionality, as well as facilitating communications-related database access. For example, call control signaling protocols are typically employed to access number portability database applications, 800/toll-free number database applications, line information database applications, calling name database applications, home location register applications, presence service databases, telephony-to-WWW domain name servers, etc.
With regard to the call setup and teardown functionality provided by call signaling protocols, it will be appreciated that a number of switching points are typically involved in the successful completion of a call. In a traditional PSTN type network, such switching points include: end offices, tandem offices, and signal transfer points. Once again, in a pure PSTN environment, SS7 signaling messages are typically employed to facilitate such call setup operations. In a converged network, such switching points may include: end offices, softswitches, media gateway controllers, media gateways, etc. In a converged network environment, a combination of SS7 and a data network-based signaling protocol (e.g., SIP, H.323, M2UA, M3UA, etc.) may be employed to provide call setup/teardown functionality. In the case of a pure data network based communication network, the SS7 signaling protocol may be replaced completely by one or more data network signaling protocols.
As the converged network environment continues to evolve and expand, the tendency of network operators to place call switching and call service database nodes within the data network component of the converged network environment is increasing. That is to say, PSTN and wireless telephone network operators are finding the economics of data network operation favorable to the placement of signaling nodes within the data sub-network of the converged network environment, as opposed to the traditional PSTN—SS7 sub-network. As such, signaling point elements that have traditionally resided within an SS7 signaling network and been assigned unique SS7 network addresses (point codes and subsystem numbers) are now being placed within a data network, such as a TCP/IP-based network, and consequently being assigned IP addresses and port numbers.
A detailed discussion of such data-network-based telephony nodes and associated access techniques and protocols can be found in commonly-assigned, co-pending International Patent Publication No. WO 00/60812, entitled Methods and Systems For Providing Database Node Access Control Functionality In A Communications Network Routing Node, the disclosure of which is incorporated herein by reference in entirety.
Shown in
It will be appreciated by those skilled in the art of SS7 communications that within an SS7 signaling network, nodes are connected via dedicated 56 kbps signaling communication links. Each signaling link provides 56 kbps of bandwidth that is dedicated to communication between a pair of connected SS7 nodes. However, in an IP-based signaling network, nodes are typically connected via much faster links (typically on the order of megabits per second, depending on the underlying physical and datalink layer technologies). These high bandwidth links may be shared by a number of IP nodes simultaneously. A given path in an IP network may be shared by traffic from a number of connections, which can be set up and torn down dynamically.
Because SS7 signaling links are dedicated to carrying SS7 traffic and have a fixed bandwidth, the addition of a new SS7 connection at SG 114 would require the physical installation of a new, dedicated 56 kbps SS7 signaling link. However, the addition of a new TCP/IP connection at SG 114 would simply require the sharing of existing broadband resources so as to create a new TCP/IP connection. Unlike the SS7 link creation scenario, the creation of a TCP/IP connection does not necessarily require the addition of new physical resources and, instead, can be performed dynamically via software. Consequently, the addition of and connection to a new IP based network node does not necessarily require the addition of a new physical communication link at SG 114. If existing bandwidth is sufficient, the addition of a new connection to SG 114 may only require the establishment of an additional TCP/IP connection between SG 114 and the node in the IP network with which communication is desired.
Returning now to
Therefore, what is needed is a method and system for allowing IP connected network elements to automatically and dynamically register their presence and routing preferences at an associated network routing node, thereby minimizing or eliminating the need for manual provisioning of such configuration tasks.
According to one aspect, the present invention includes a signaling gateway (SG) that is capable of providing inter-network message routing services in a converged telephony-data network environment. The SG includes a dynamic routing key registration feature which allows Internet protocol (IP) sockets to dynamically register/de-register their routing information with the signaling gateway and subsequently direct traffic towards or away from themselves without the need for manual operator intervention.
In one embodiment, an SG includes a self-registering data communication module (sDCM) that is adapted to receive and process dynamic routing key registration messages from associated IP nodes over existing transmission control protocol/IP (TCP/IP) connections. Such dynamic routing key registration messages may include information that is used to register a new routing key association with a TCP/IP connection, de-register an existing routing key associated with a TCP/IP connection, or modify routing key information associated with an existing TCP/IP connection. It is understood that a TCP/IP connection may be identified locally on a signaling gateway by a data structure known as a socket. Thus, in order to allow dynamic registration of routing keys associated with a TCP/IP connection, a signaling gateway may associate the routing keys with a local socket for the connection.
As used herein, the term “routing key” refers to a parameter or combination of parameters to be extracted from or examined in a call signaling message to determine where to route the call signaling message. Exemplary SS7 routing keys include: originating point code (OPC), destination point code (DPC), subsystem number (SSN), and circuit identifier code (CIC). These routing keys have conventionally been used by SS7 nodes, such as signal transfer points to route call signaling messages to other SS7 signaling nodes. According to the present invention, IP nodes in an IP network are permitted to dynamically register SS7 routing keys in an SS7/IP signaling gateway to direct traffic to or away from themselves. This dynamic registration capability in a signaling gateway node avoids the difficulties of manual registration associated with conventional routing solutions.
The sDCM card employs a dual routing key table database structure that includes both a static routing key table and a dynamic routing key table. Received dynamic routing key registration messages are used to modify information in the dynamic routing key table only. During subsequent signaling message routing operations, the dynamic routing key table is searched first. The failure to locate a suitable or matching routing key entry in the dynamic routing key table results in a secondary or default search of the static routing key table.
The functions for facilitating dynamic or self-registration of IP-based network elements are described herein as modules or processes. It is understood that these modules or processes may be implemented as computer-executable instructions embodied in a computer-readable medium. Alternatively, the modules or processes described herein may be implemented entirely in hardware. In yet another alternative embodiment, the modules or processes described herein may be implemented as a combination of hardware and software.
The processes and modules for providing dynamic routing key registration functionality are described below as being associated with cards or subsystems within a gateway routing node. It is understood that these cards or subsystems include hardware for storing and executing the processes and modules. For example, each card or subsystems described below may include one or more microprocessors, such as an x86 microprocessor available from Intel Corporation or a K series microprocessor available from AMD Corporation, and associated memory.
Accordingly, it is an object of the present invention to provide a routing node that facilitates dynamic self-registration by Internet protocol nodes to which it is connected.
It is another object of the present invention to provide a routing node that facilitates dynamic self-de-registration by Internet protocol nodes to which it is connected.
It is yet another object of the present invention to provide a routing node that facilitates dynamic self-modification of routing key information by Internet protocol nodes to which it is connected.
It is yet another object of the present invention to provide a method and system for allowing IP network elements to automatically direct traffic towards or away from themselves by sending messages to a routing node.
It is yet another object of the present invention to provide a system and method for obtaining routing key information associated with the routing of signaling messages at a routing node that includes performing a primary lookup in a first routing key table, followed by a default lookup in second routing key table in the event that a suitable routing key entry is not located in the first routing key table.
It is yet another object of the present invention to provide a system and method for allowing a routing key delivered by a registration message, to override all existing, similar routing key entries in a routing key table maintained at a routing node so as to cause the routing node to direct all subsequent signaling traffic associated with the routing key to the TCP connection over which the registration message was sent.
Some of the objects of the invention having been stated hereinabove, other objects will become evident as the description proceeds, when taken in connection with the accompanying drawings as best described hereinbelow.
Disclosed herein are several embodiments of the present invention, all of which include a network element that performs functions similar to that of a traditional telecommunications network packet routing switch, such as a signaling gateway (SG) routing node. Each of the embodiments described and discussed below, employs an internal architecture similar to that of high performance signal transfer point (STP) and SG products which are marketed by Tekelec as the Eagle® STP and IP7 Secure Gateway™, respectively. A block diagram that generally illustrates the base internal architecture of the IP7 Secure Gateway™ product is shown in
Application subsystem 256 includes application cards that are capable of communicating with the other cards through the IMT buses. Numerous types of application cards can be incorporated into SG 250, including but not limited to: a link interface module (LIM) 258 that provides SS7 links and X.25 links, a data communication module (DCM) 260 that provides a TCP/IP interface to external nodes and an application service module (ASM) 262 that provides global title translation, gateway screening and other services. A translation service module (TSM) 264 may also be provided to support triggered local number portability service. Again, it should also be appreciated that, in addition to conventional SS7 LIM cards, one or more DCM cards can be employed in a similar manner to provide for the transport of Internet Protocol (IP) encapsulated SS7 messages over an IP network, as described in the above referenced Feature Notice IP7 Secure Gateway™ Release 1.0 publication.
MASP pair 272 implement the maintenance and administration subsystem functions described above. As the MASP pair 272 are not particularly relevant to a discussion of the flexible routing attributes of the present invention, a detailed discussion of their function is not provided herein. For a comprehensive discussion of additional MASP operations and functionality, the above-referenced Tekelec IP7 Secure Gateway™ and Eagle® STP publications can be consulted.
Given the SG routing node internal architecture shown in FIG. 3 and briefly discussed above, it will be appreciated that one fundamental operation of the SG 270 involves the receipt of a signaling message at LIM 276 from an SS7 network and the subsequent internal routing of this message to sDCM 278 for transmission via a TCP/IP communication socket to one of the pair of MGC nodes 284 or 286, and vice versa. Since the receipt and subsequent processing of SS7 message signaling units (MSUs) by a LIM card is not particularly relevant to the dynamic routing key registration functionality of the present invention, a detailed discussion of such LIM operation is not provided herein. Instead, the above mentioned Eagle® Feature Guide can be consulted for a detailed discussion of LIM operation and functionality.
It should be noted that it is often the case that MGC nodes, such as those shown in
Shown in
Within a message packet, synch field 302 is used to identify the message packet as being of a transport adapter layer interface (TALI) format. As used herein “TALI” refers to the transport adapter layer interface as described in Internet Engineering Task Force (IETF) Internet Draft <draft-benedyk-sigtran-tali-01.txt> entitled “Transport Adapter Layer Interface,” June 2000, the disclosure of which is incorporated herein by reference in its entirety. TALI is a protocol that defines procedures and message structures for communicating SS7 messages over a stream-oriented packet-based network, such as a TCP/IP network. However, the present invention is not limited to using TALI over TCP/IP to communicate between SS7 and IP nodes. In an alternative embodiment of the invention, stream control transmission protocol (SCTP) over IP may be used. The stream control transmission protocol is described in RFC 2960: Stream Control Transmission Protocol, the disclosure of which is incorporated herein by reference in its entirety.
Opcode field 304 identifies the type of operation associated with the message. For dynamic routing key registration related messages, an opcode value equal to “mgmt” is used. Length field 306 simply indicates the length of the message (e.g., bits, octets, etc.). Primitive field 308 is used to specify a group of “mgmt” operations to which the message is applicable. A primitive field value of “rkrp” signifies a dynamic routing key registration message. RKRP operation field 314 specifies a particular operation within the group of allowed operations identified by the primitive. Message data field 312 employs a structure and contains information that are dependent on the combination of opcode/primitive/operation field values (i.e., each combination could employ a different message data structure).
RKRP operation field 314 contains an integer value that is used to identify the desired “rkrp” operation. Request/reply field 316 identifies whether the “rkrp” message is a request, sent by an IP node to the SG, indicating a particular type of “rkrp” action, or a reply to a previous request. Success/failure code field 318 provides a success/failure indication value as part of the reply back to an IP node for each processed request, while registration data field 312 includes specific information related to the creation, termination, or modification of a routing key—TCP/IP socket association.
It will be appreciated that RKRP operation field 314, request/reply field 316, success/failure code field 318, and registration data field 312 are common to all RKRP operation related messages. The primary purpose of requiring the data structures for all RKRP operations to begin with these same fields, is to provide a means for a receiver to reply to unknown RKRP messages in a consistent manner. When an sDCM card receives an RKRP request message that is not understood, the request is converted into a reply and the success/failure code field value is used to indicate that the operation is not supported (e.g., with an RKRP reply code of ‘Unsupported ‘rkrp’ operation, 3’).
As discussed above, the specific type and quantity of information contained within a routing key registration message is a function of the character of the particular routing key with which it is associated. Shown in
As indicated in
It should be noted that the RKRP flag is a 2-byte field that provides 16 possible flags that control various aspects of the dynamic routing key registration operation. In one embodiment, Bit 0 serves as an override bit that is used to control how a TCP/IP socket association for a particular routing key should be manipulated. As such, the RKRP flag determines if the dynamic routing key update transaction is intended to add a specified socket association in a “load-sharing” mode or if a new association should replace (i.e., override) all existing socket associations. It is through the use of the RKRP flag that a TCP/IP capable node, via an override-designated TCP/IP socket registration request, can re-direct and subsequently receive all traffic associated with a particular routing key.
Shown in
In the case of an outbound signaling message routing operation, it will be appreciated that routing database update manager process 416 effectively controls the sequence in which the dynamic and static table lookups occur. More particularly, the dynamic routing key table 422 is always searched initially, followed by a search of the static table 424 in the event that no match is located in the dynamic data table 422. sDCM 400 includes a message transport part (MTP) level 3 process 430 and additional functional processes beyond those shown in FIG. 6. However, it will be appreciated that the MTP level 3 process and other such additional functional processes are not particularly relevant to a discussion of the present invention, and are therefore not discussed in detail herein. An in depth discussion of such higher level processing functionality can be found in the above-referenced Tekelec SG and STP Feature Notice Publications.
Again, it will be appreciated that the message packets received and transmitted by the sDCM card 400 may include TALI type messages, session initiation protocol (SIP), M2UA, M3UA, SUA, H.323, SCTP/IP, or other signaling protocols that may be transported via TCP/IP or similar IP based protocols. Preferred packet formats for encapsulating various types of SS7 messages in IP packets are described in the above-referenced TALI IETF Internet Draft. Furthermore, functionality associated with the TALI protocol is described in commonly-assigned, co-pending International Patent Publication No. WO 00/76134, the disclosure of which is incorporated herein by reference in its entirety. Again, it will be appreciated that the concepts described in this disclosure are not dependent on the above-referenced TALI signaling protocol. Other functionally similar signaling protocols are intended to be within the scope of the present invention. For example, the IETF SUA/M3UA protocol may be used.
As indicated in
It should be appreciated that, in a preferred embodiment, the structure of static routing key table 424 is similar to that of dynamic routing key table 422, illustrated in FIG. 7. The difference between these two routing key tables is primarily how they are updated and the order in which they are accessed during a routing key lookup operation. More particularly, static routing key table 424 is adapted to maintain a set of routing key entries that cannot be updated or modified by routing key registration signaling messages originated by another network element. Such routing key registration type signaling messages may effect changes only in the dynamic routing key table 422.
Once again, it will be appreciated that the database structures and tables described above are merely illustrative of the types of data that can be employed to provide the functionality of an sDCM of the present invention.
In addition to sDCM functional processes,
In any event, a dynamic routing key registration request message is received on the socket 0 connection via TCP/IP socket layer 404. Socket layer 404 performs lower protocol level processing on the incoming message packet and subsequently passes message to socket 0 R/W process 408. Socket 0 R/W process 408 temporarily buffers the received message and forwards the message to TALI application layer 410. TALI application layer 410 receives the incoming TALI dynamic routing key registration request message and performs a variety of TALI-specific message administration processes. TALI layer 410 subsequently directs the message to SS7IPGW application layer 412, where the message is determined to be a dynamic routing key registration request message. In response to identifying the message as a dynamic routing key registration request, application layer 412 directs the message to the dynamic routing key registration process 414.
In one embodiment, dynamic routing key registration process 414 extracts and re-formats relevant information contained in the received message in a manner such that the information may be effectively used by routing database update manager 416. In an alternate embodiment, routing database update manager process 416 may be capable of receiving a dynamic routing key message and directly processing the message.
In any event, routing database update manager process 416 uses the information contained within or gleaned from the dynamic routing key registration message to administer an update of dynamic routing key table 422. Again, such dynamic routing key table update operations might include the addition of a new TCP/IP socket association, the removal of an existing TCP/IP socket association, or modification of routing key information associated with an existing TCP/IP socket.
Presented in
It will be appreciated that in one embodiment, a TALI dynamic routing key registration acknowledgment message is simply a copy of the received dynamic routing key registration message, with the request/reply field 316 (as shown in
Shown in
As such, routing database update manager process 416 directs the acknowledgment message to dynamic routing key registration process 414, which in turn passes the message to SS7IPGW application layer 412. SS7IPGW layer 412 determines that the message is to be transmitted via an on-card TCP/IP socket and subsequently directs the acknowledgment message to TALI application layer 410. TALI application layer 410 appends appropriate TALI header information to the message and passes the message to the appropriate socket R/W process. In this particular example, the acknowledgment message is passed to the socket 0 R/W process 408, and eventually transmitted to the sender of the original routing key registration message via TCP/IP socket layer 404.
Shown in
It is assumed in
Shown in
In the example scenario illustrated in
It will be appreciated that the routing of an outbound signaling message is a complex operation and entails a number of additional steps above and beyond those discussed herein. As these additional steps are not particularly relevant to the present invention, they are not explicitly presented in this disclosure. A more detailed discussion of overall signaling message routing operations may be found in the above referenced Eagle® Feature Guide and Feature Notice IP7 Secure Gateway™ publications.
Referring to
In the event that the lookup in the dynamic routing key table does not yield a matching routing key entry, a secondary or default lookup operation is performed in the static routing key table 424 (ST8). If a match is found the status of a selected TCP/IP socket is determined (ST4). Again, it will be appreciated that in the event that multiple sockets are associated with the matching static routing key, a specific TCP/IP socket may be selected based on a signaling link selector (SLS) parameter contained in the signaling message. In the event that the selected TCP/IP socket is available, the signaling message is transmitted via the selected socket (ST5). In the event that the selected socket is not available, and there are no other available sockets associated with the matching static routing key, a determination is made as to whether the destination point code associated with the destination of signaling message is accessible via a peer communication module (sDCM, DCM, LIM, etc.) that is currently provisioned in the signaling gateway routing node (ST6). If such a peer communication module exists in the routing node, the signaling message is forwarded to that communication module for routing/transmission (ST7). If such a peer communication module does not exist, or if there is no routing key match found in the static routing key table 424 then the signaling message may be discarded (ST9).
The dynamic registration procedures described herein are especially well suited to provide reliability in an IP telephony network that utilizes IP-base call control nodes, such as media gateway controllers (MGCs), to set up and tear down calls.
One of the connections 1500 and 1502 may be a primary connection over which communication occurs and the other connection may be a backup connection for carrying traffic in response to failure of the first connection. Similarly, one of the connections 1504 and 1506 may be a primary connection over which communication occurs and the other connection may be a backup connection for carrying call signaling traffic only in response to failure of the first connection. The present invention is not limited to two connections between communicating nodes, and it is understood that any number of primary and backup connections could be used.
MGCs 284 and 286 preferably monitor the status of primary connections 1500 and 1504. For example, MGCs 284 and 286 may determine whether the sockets associated with connections 1500 and 1504 are functioning properly. In response to detecting a failure on one of the primary connections 1500 or 1504, the MGC that manages the failed connection preferably sends a routing key registration message over the backup connection to notify sDCM 278 to start sending data over the backup connection. It would seem that this would result in two entries in dynamic routing key table 422 having the same routing keys. However, as discussed above with respect to
The same automatic changeover procedure can be used to switch communication between a primary IP node and a backup IP node. For example, MGC 284 may be a primary IP node and MGC 286 may be a backup IP node. If MGC 284 fails, MGC 286 may detect this failure using inter-MGC communications and send a routing key registration request to SG 270 to direct traffic originally routed to MGC 284 to itself. It is understood that in this situation, MGC 286 would store state information of MGC 284 so that switching would occur seamlessly.
It will be appreciated that various details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation—the invention being defined by the claims.
This application claims the benefit of U.S. Provisional Patent Application No. 60/198,967, filed Apr. 21, 2000, the disclosure of which is incorporated herein by reference in its entirety.
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