As an alternative to traditional switched circuit networks, telecommunications service providers have discovered that voice telephone calls may be routed over IP networks.  Due to the fact that the Internet is not presently subject to the same international regulations as are traditional telephone networks, routing telephone calls over the Internet tends to be less expensive.  Additionally, an IP routed voice telephone call requires much less bandwidth, and thus less cost, than a voice telephone call placed over a traditional telephone network.  Further, IP technology advances and is entered into the marketplace at a much faster rate than traditional telecommunication technology.  Thus, in order to be competitive, telecommunications service providers have begun to use IP routing as a way to offer customers access to the latest technological improvements. 
Presently, however, there is no centralized system for routing voice telephone calls over an IP network.  Each operator of a gateway is responsible for determining the routes for its own outgoing calls.  Typically, gateway operators rely on traditional IP routing algorithms, which are designed to handle routing of computer generated data packets.  Traditional IP routing algorithms attempt to strike a balance between the concerns of minimum delay and maximum reliability.  Thus, using traditional IP routing algorithms, a voice telephone call will be routed to any destination gateway that happens to satisfy a set of predetermined shortest path and acceptable data loss parameters. 
The routing of voice telephone calls, however, involves a significant concern that is not shared by traditional IP routing algorithms.  This additional concern is the monetary cost of routing a voice call to a particular destination gateway.  As in traditional switched circuit networks, Internet telephony gateways impose fees for the service of terminating a voice call.  Traditional IP routing algorithms are not able to detect and compare the varying price schedules that may be imposed by various Internet telephony gateways.  Thus, source gateways are not able to discriminate between destination gateways based on monetary costs. 
One way a gateway operator can establish the cost for IP telephony services is by negotiating directly with other gateway operators a fee for terminating each other's calls.  These gateway operators could identify each other and establish a bilateral agreement or a multilateral agreement.  This approach closely resembles that of the international circuit switch telephony network, where providers in each country have established bilateral and multilateral agreements with each other.  A significant hurdle for this routing implementation, however, is the large number of business relationships that must be negotiated and maintained.  For example, should 1,000 local operators decide to interconnect via bilateral agreements, 999,000 separate agreements would be necessary.  Interconnection through a centralized system, however, would require only 1,000 separate business agreements, each with a separate operator. 
Another disadvantage with a bilateral agreement model is that the gateway operators are not able to react quickly and intelligently to changing market forces because the bilateral agreements are generally long-term contracts.  For example, when there is a sudden increase in demand for terminating calls to a particular area, the gateway operator in that area is unable to increase his terminating charges and take advantage of a demand.  Additionally, a bilateral agreement model or the multilateral agreement model are too cumbersome for the gateway operators to set call pricing based on selected call number ranges (any given subset of all possible telephone numbers).  This is especially true if the total number of telephone numbers comprising a called-number range is too small.  For example, it may be too cumbersome for the gateway operators to negotiate a specific call pricing plan for a specific customer with less than 100 numbers within their called-number range. 
In order to assist gateway operators with routing decisions, a centralized system can be provided where Internet Telephony Service Providers (ITSPs) become members of this centralized system.  The centralized system is generally referred to as a clearinghouse.  Clearinghouse services attempt to capture IP telephony traffic in order to receive the revenue associated with that traffic.  By joining a clearinghouse service, an ITSP stimulates traffic growth on its network and gains access to other gateways.  The clearinghouse not only routes and authorizes IP telephony traffic, but also handles the billing for the call. 
One function of a clearinghouse is to link source gateways to destination gateways within the clearinghouse.  However, the advantages gained with a clearinghouse are limited in that the ITSP cannot go beyond its clearinghouse to access gateways of another clearinghouse.  Thus, a need exists for a system to support the linking of separate clearinghouse services.  Specifically, there is a need in the art for a gateway operator to be able to easily locate gateways with desirable characteristics in another clearinghouse.  There is a further need for a system and method to support recording and billing of the transaction between the two gateways.