The present invention relates to signaling transport protocol extensions for load balancing and server pool support, and in particular to the provision of a name translation mechanism within such a signaling transport protocol.
FIG. 1 shows a signaling transport protocol stack as defined by the Internet Engineering Task Force IETF for the provision of standard signaling connection control part SCCP services and standard message transfer part layer 3 MTP3 services.
As shown in FIG. 1, on top of the Internet protocol IP there runs a stream control transmission protocol SCTP. The stream control transmission protocol SCTP has been developed to improve the quality of service capabilities which are particularly required for real time communication applications.
As also shown in FIG. 1 on top of the stream control transmission protocol SCTP runs, e.g., the signaling connection control part SCCP user adaptation layer SUA and/or the MTP3 user adaptation layer M3UA according to the SIGTRAN protocol stacks defined by the Internet Engineering Task Force IETF. All these protocols and related implementations are commonly known in the art and therefore will not be explained in detail.
The SIGTRAN protocol stack shown in FIG. 1 is used to transport signaling messages using the common channel signaling system No. 7 also referred to as CCS No. 7 in the following: over the IP network. Typically, mobile cellular communication networks rely to a very large extent on signaling connection control part SCCP services. Specific examples are the radio access network application part RANAP for third generation cellular mobile communication networks and the base station system application part BSSAP for second generation cellular mobile communication networks. Yet another example for an SCCP service is the transaction capability application part TCAP used by the mobile application part MAP, the intelligent network application part INAP, and the customized application mobile for enhanced logic CAMEL.
When migrating the common channel signaling system services to an Internet protocol IF backbone infrastructure, all these protocols must be supported via SUA/SCTP/IP. However, the migration of CCS7 SCCP services to an IP backbone infrastructure leads to problems since these services and their addressing mechanisms originate from a circuit switched environment. I.e., the SCCP services use either a destination point code DPC and subsystem numbers SSN or a global title GT to address specific users. Therefore, both addressing mechanisms point to a single destination in the network which has been the exact requirement for the circuit switched world.
To the contrary, the migration to an Internet protocol IP based backbone network will provide new possibilities to enhance service provisioning. Recently, server pools have been proposed to increase service availability and capacity in future mobile cellular communication networks. Server pools are seen from the outside as a single logical entity. A user requesting a service from such a server pool does not consider which actual physical server is going to handle his request.
However, while from the viewpoint of network, e.g., characteristics it may be desirable to have an equal load balancing over all servers comprised in the server pool, existing addressing mechanisms do not support such a load balancing between different servers in a server pool.
A possible solution using available technologies is to go up to the SCCP protocol level and to carry out the selection on this user layer. Then the request for the handling of a service by a specific server in a server pool must be retransmitted to the selected server. This solution causes an additional data exchange overhead and service provision delay during service execution and consumes additional processing capacity
In view of the above, the object of the present invention is to achieve an improved support for the introduction of server pools in packet based networks and to achieve transparency for applications.
According to the present invention this object is achieved by a communication apparatus running a protocol stack implementation for interworking between a signaling source node and a signaling target node, comprising a first protocol implementation unit adapted to run a signaling control layer SCTP of the protocol stack on top of a packet transfer network IP for exchange of signaling data via at least one signaling association, a second protocol implementation unit adapted to run a user adaptation layer SUA of the protocol stack on top of the signalling control layer SCTP for support of signalling connection control services SCCP used by the signaling source node, wherein a name mapping unit is adapted to receive a signaling target node name from the signaling source node and to map the signaling target node name into a peer signaling association.
Therefore, the present invention allows to support server pooling in SUA with increased system fault tolerance due to the provision of server pools. Additional benefits are dynamic system scalability, i.e. the ability for adding and removal of servers without reconfiguration of remaining servers.
Further, the present invention achieves real time name translation, e.g., through provision of local copies of data relating to name mapping in each network node and/or host. In addition, the name translation mechanism according to the present invention supports association handling, i.e. multiple interactions between a client SCCP user and a destination server in a server pool having a destination name. Also, the name translation mechanism according to the present invention allows for the use of name mapping related data and services in a distributed manner across an operational scope of the Internet protocol IP network. The name mapping unit itself may in this case be implemented, e.g., as agent in different network nodes.
As server pools are usually addressed on a name basis and the related addresses are then resolved within the inventive name transition mechanism, new servers may register in server pools in an automatic manner leading to a significant decrease of operation administration and maintenance costs since new server addresses must not be administered manually in every node of the Internet protocol IP network.
Yet another important benefit of the present invention is that upper layer protocols like SCCP and/or MTP3 must not decide on load balancing. This functionality is encapsulated in the name translation mechanism provided for the SUA layer and thus may be changed and renegotiated during operationxe2x80x94e.g., depending on timexe2x80x94without affecting the upper user layer. This leads to a better load balancing within the server pool.
Further, due to the encapsulation of the name translation mechanism in the lower SUA layer of the SIGTRAN stack the inventive solution is applicable to all SUA users.
According to a preferred embodiment of the present invention the name mapping unit of the communication apparatus comprises a mapping data interface unit adapted to distribute and/or receive signaling association attributes via the signaling control layer SCTP.
This preferred embodiment of the invention allows for a name translation interworking between a plurality of communication apparatuses in the network to increase fault tolerance.
According to yet another preferred embodiment of the present invention the name mapping unit also comprises a memory unit adapted to store signaling association attributesxe2x80x94used in the context of addressing of signaling messagesxe2x80x94locally in the communication apparatus.
According to this preferred embodiment of the present invention mapping related data is updated only in a single data base and may then be distributed in the Internet protocol IP network via local copies of the mapping related data. A periodic update of name space and/or attribute data in a data base improves data consistency. Further, this feature supports real time name mapping through avoidance of messaging for name space and/or attributed data.
According to yet another preferred embodiment of the present invention the target node name resolution unit is adapted to map a destination name into the peer signaling association according to a specified algorithm. Examples for such algorithms are query response data base mechanism such as ENRP/DDP. Yet another alternative is a table lookup technique.
This preferred embodiment of the present invention increases flexibility through a specification of a name mapping mechanism. In conclusion, the mapping acts as generic interface capable of interworking with different name spaces.
According to yet another preferred embodiment of the present invention the target node name resolution unit is of a client/server type responding to name translation requests from signaling source node clients in a local and/or remote manner.
The client/server architecture increases fault tolerance of the target node name resolution unit. Further, it enables backup server selection or, equivalently, the implementation of a server hunting and takeover procedure. Overall, load balancing for a plurality of name mapping processes in the Internet protocol IP network may be improved.
According to yet another preferred embodiment of the present invention the target node name resolution unit is further adapted to consider at least one criterion selected from a group comprising target node capability, target node load and routing criteria association attributes to map the signaling target node name into the peer signaling association.
This preferred embodiment of the present invention achieves optimal name mapping in view of criteria that may change over time.
According to yet another preferred embodiment of the present invention the name mapping unit further comprises a fault management unit adapted to detect an inoperative peer signaling association and/or an inoperative signaling transport address in a peer signaling association and to select another signaling transport address under the same destination name.
This preferred embodiment of the present invention is of particular advantage during an Internet protocol IP network failure detection and a subsequent automatic recovery. In other words, the name translation service may survive, e.g., in isolated communication islands.
Also, this feature enables improved mapping data consistency and supports failure mechanisms between different instances, e.g., servers comprised in a server pool.
Further, this preferred embodiment of the present invention may be used to support maintenance operations in the network.
Similar advantages as outlined above with respect to the communication apparatus are also achieved with the inventive method of running a protocol stack implementation for interworking between a signaling source node and a signaling target node.
Still further, the present invention is also provided to achieve an implementation of the inventive method steps on computer or processor systems. In conclusion, such implementation leads to the provision of computer program products for use within a computer system.
The programs defining the functions of the present invention can be delivered to a computer/processor in many forms, including, but not limited to information permanently stored on a non-writable storage medium e.g., read only memory devices such as ROM or CDROM discs readable by processors or computer I/O attachments; information stored on writable storage media, e.g., floppy discs and harddrives; or information conveyed to a computer/processor through communication media such as a network and/or telephone network and/or Internet or any other suitable interface devices. It should be understood that media when carrying processor readable instructions implement the inventive concept to represent alternate embodiments of the present invention.