BACKGROUND OF THE INVENTION Technical Field of the Invention The present invention relates generally to telecommunication networks. More particularly, and not by way of limitation, the invention is directed to a method of establishing a connection between an originating media gateway and a terminating media gateway over an Internet Protocol (IP) network.

Description of Related Art FIG. 1 is a simplified block diagram of an existing network architecture 10 for providing connections between Media Gateways (MGs) through either an IP network 16 or an Asynchronous Transfer 'Mode (ATM) network 17. Users access the network architecture through one of a plurality of access networks lla-lld. An MG 12 is responsible for establishing connections from the access networks 11a,lib towards other access networks connected to the MG or to other MGs such as MG 13 and MG 14. To establish connections to other MGs, the MG 12 may establish an IP bearer through an IP Network 15,16 or an Asynchronous Transfer Mode (ATM) bearer through the ATM Network 17. When establishing a call connection over an IP network or an ATM network, a Media Gateway Controller (MGC) 21 in the access network receives a call setup request from a user and sends a number of H.248 signaling messages to an originating MG and a terminating MG. The MGs establish the actual network connection and handle the flow of data (media) from the originating user to the terminating user. The MGC obtains information from the originating MG that o

needs to be passed to the terminating MG for establishment of the connection over IP or ATM. FIG. 2 is a signaling diagram illustrating the flow of messages between network nodes when establishing a call connection over an IP network using existing procedures. To establish an IP bearer in a so-called "delayed backward setup" sequence, the MGC 21 must obtain the IP address from the originating MG-I 22 and forward it to the terminating MG-2 23. Thus, the MGC sends an Add message 24 to the originating MG-I, which returns an AddReply message 25 to the MGC with the IP address of MG-I. The MGC then sends an Add message 26 to the terminating MG-2. MG-2 then seizes an IP interface and sends information about the interface to the MGC in an AddReply message 27. The MGC then forwards the information about the IP interface to the originating MG-I in a Modify message 28. MG-I then seizes an IP interface, and sends information about the interface to the MGC in a ModifyReply message 29. The MGC then forwards the information about the IP interface to the terminating MG-2 in a Modify message 30. Finally, MG-2 returns a Modify message 31 to the MGC. Thus, there are a total of 8 signaling messages required for the establishment of the IP connection. The number of messages needed for the establishment of a connection over an IP network is greater than the number needed for an ATM network. This creates a problem because the processing of the messages in the nodes is expensive, and the larger number of messages adversely affects the performance of the system. SUMMARY OF THE INVENTION The present invention provides a connection method and a Media Gateway Controller (MGC) that overcome the problem of the prior art by reducing the number of signaling messages required to establish the connection. Thus, in one aspect, the present invention is directed to a method of establishing a connection between an originating MG (MG- 1) and a terminating MG (MG-2) over an IP network. The MGC obtains and stores the IP addresses for all of the MGs in the MGCs domain prior to initiating the establishment of the connection. Subsequent to storing the IP addresses for all of the MGs in the MGCs domain, the MGC receives a call access request message from a user requesting that a connection be established between the originating MG-I and the terminating MG-2. The MGC initiates the establishment of the connection by sending a first connection setup message to the terminating MG-2 without contacting the originating MG-I to obtain the originating MG-I's IP address. Instead, the first setup message includes the originating MG-I IP address that was stored in the MGC. Thereafter, the MGC obtains the IP address of MG-2, obtains information regarding IP interfaces seized by MG-I and MG-2 for the connection, and provides the IP addresses and IP interface information to both MG-I and MG-2 for establishment of the connection. In another aspect, the present invention is directed to a method of establishing a connection between an originating MG-I and a terminating MG-2 over an IP network. The method includes the steps of obtaining and storing by a MGC, the IP addresses for all of the MGs in the MGCs domain; receiving in the MGC, a call access request message from a user requesting that a connection be established between MG-I and MG-2; and sending a first connection setup message from the MGC to MG-2 without contacting MG-I to obtain MG-I's IP address. The first setup message includes MG-I's IP address that was stored in the MGC. The method also includes receiving in the MGC, a first reply message from MG-2 that includes an IP address for MG-2 and identifies an IP interface seized by MG-2 for the connection; sending a second connection setup message from the MGC to MG-I that includes MG-2's IP address; and receiving in the MGC, a second reply message from MG-I that identifies an IP interface seized by MG-I for the connection. The method also includes sending a third connection setup message from the MGC to MG-2 informing MG- 2 of the IP interface seized by MG-I for the connection; and establishing the connection between MG-I and MG-2 using the identified IP interfaces and the IP addresses sent to each MG. In yet another aspect, the present invention is directed to a telephony server for establishing a connection between an originating MG-I and a terminating MG-2 over an IP network. The telephony server includes a memory for storing the IP addresses for all of the MGs in the telephony server's domain; signaling means for receiving a call access request message from a user; and connection establishment means connected to the memory and the signaling means. The connection establishment means is adapted to provide the stored IP address of MG-I to MG-2; obtain an IP address from MG-2; provide the obtained IP address of MG-2 to MG-I; request MG-I and MG-2 to seize IP interfaces for the connection; obtain information regarding the IP interfaces seized by MG-I and MG-2; and provide the IP interface information to both MG-I and MG-2 for establishment of the connection.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, the essential features of the invention will be described in detail by showing the prior- art and two preferred embodiments, with reference to the figures of the attached drawings. FIG. 1 is a simplified block diagram of an existing network architecture for providing connections between Media Gateways (MGs) through either an IP network or an ATM network; FIG. 2 is a signaling diagram illustrating the flow of messages between network nodes when establishing a call connection over an IP network using existing procedures; FIG. 3 is a signaling diagram illustrating the flow of messages between network nodes when the MGC obtains and stores IP addresses for the MGs in its domain; and FIG. 4 is a signaling diagram illustrating the flow of messages between network nodes when establishing a call connection over an IP network in accordance with the teachings of the present invention.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, the MGC obtains the IP addresses for all of the MGs in its domain prior to receiving a request for a call connection. The IP addresses may be obtained when each MG first connects to the MGC, or when the first connection is going to be established. FIG. 3 is a signaling diagram illustrating the flow of messages between network nodes when the MGC obtains and stores IP addresses for the MGs in its domain. The MGC 21 sends an Add message 33 to the originating MG-I 22, requesting MG-I's IP address. This may be done by requesting MG-I to seize an ephemeral IP bearer. In response, MG-I returns an Add/Reply message 34 to the MGC with the IP address of MG-I. The ephemeral bearer is then released. At 35, the MGC stores the IP address of MG-I. The MGC then sends an Add message 36 to the terminating MG- 2 23 requesting MG-2's IP address. Again, this may be done by requesting MG-2 to seize an ephemeral IP bearer. MG-2 returns an Add/Reply message 37 to the MGC with the IP address of MG-2, and the ephemeral IP bearer is then released. At 38, the MGC stores the IP address of MG-2. Because the MGC 21 stores the IP addresses of all of the MGs in its domain, the MGC does not have to query an originating MG for its IP address when a connection is requested. Therefore, the MGC starts the connection sequence by contacting the terminating MG. In this manner, two messages in the connection sequence are eliminated (the Add message 24 and the AddReply message 25 through which the MGQ" obtained the IP address of the originating MG) . FIG. 4 is a signaling diagram illustrating the flow of messages between network nodes when establishing a call connection over an IP network in accordance with the teachings of the present invention. Since the MGC 21 has previously stored the IP address of the originating MG-I 22, the sequence begins when the MGC sends an Add message 41 to the terminating MG-2. MG-2 then seizes an IP interface and sends information about the interface to the MGC in an AddReply message 42. The MGC then forwards the information about the IP interface to the originating MG-I in an Add message 43. MG-I then seizes an IP interface, and sends information about the interface to the MGC in an AddReply message 44. The MGC then forwards the information about the IP interface to the terminating MG-2 in a Modify message 45. Finally, MG-2 returns a Modify message 46 to the MGC, and the connection is established. Although a preferred embodiment of the present invention has been illustrated in the accompanying drawings and described in the foregoing Detailed Description, it is understood that the invention is not limited to the embodiment disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the scope of the invention. The specification contemplates any all modifications that fall within the scope of the invention defined by the following claims.