Abstract:
To provide a gateway system capable of handling more gateways in one gatekeeper by dividing gatekeeper functions and mounting a part of the H.323 gatekeeper functions in a gateway apparatus. The gateway apparatus includes a proxy gatekeeper, and a gateway. A master gatekeeper and the gateway apparatus form an H.323 zone, and communicate with gatekeepers and endpoints in other zones via a network address &amp; port number translator.

Description:
This application is a continuation of application Ser. No. 09/604,879, filed Jun. 28, 2000, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a gateway system, gateway system configuring method, and a gateway apparatus in an H.323 specification communication system, especially to the gateway system, it&#39;s configuring method, and a gateway apparatus which is capable of handling more gateways in one gatekeeper by dividing H.323 gatekeeper functions and mounting part of the gatekeeper functions, in each gateway apparatus. 
     2. Description of the Prior Art 
     Up to now, H.323 gateway systems have been used for relay between communication conforming to ITU-T recommendation H.323, which is a standard specification of a service quality non-guaranteed LAN and communication conforming to another standard different from the recommendation H.323 so as to perform protocol conversion. In an H.323 model, one zone is configured by one gatekeeper, and one or more endpoint(s) (gateway(s) or H323 terminal(s)). The gatekeeper performs address translation, access conversion control, bandwidth management, or the like, and controls the gateway(s). If a number of gateways in one zone increases, convergence of gatekeeper processing is avoided by providing a plurality of gatekeepers. Nevertheless, since a gateway can be registered in only one gatekeeper at the same time, gateways are separated into a plurality of zones constituted for every gatekeeper. 
     BRIEF SUMMARY OF THE INVENTION 
     Object of the Invention 
     There are several problems with the use of the conventional H.323 technology described above. 
     A first problem is that, if a plurality of zones is constituted in a state of a number of gateways being not changed, a call loss probability becomes large. This is because, the smaller the scale a zone becomes, the smaller a mass effect becomes. On the contrary, to maintain a reasonable call loss probability, a number of gateways must unfortunately increases. 
     A second problem is that, in the case of a one-zone configuration, a number of gateways that can be contained is limited by the capacity of a gatekeeper. In order to contain more gateways in one zone, it is necessary to use a higher-performance gatekeeper, or it is necessary to separate gateways into a plurality of zones and add an appropriate number of gatekeepers. This causes an increase in capital expense or operation expense. 
     The present invention is to provide a gateway system and gateway system configuring method for solving the above-described problems. The gateway system handles more gateways in one gatekeeper by dividing gatekeeper functions in an H.323 specification communication system, and mounts parts of the gatekeeper functions in a gateway apparatus. 
     SUMMARY OF THE INVENTION 
     In order to solve the above-described problems, a gateway system, it&#39;s configuring method and a gateway apparatus according to the present invention in an H.323 specification communication system is characterized in that the gateway system comprises a master gatekeeper having a gateway control function including an address translation function for communicating with other zones, a zone management function, and a call control signaling-function, a proxy gatekeeper having the address translation function and zone management function out of the gateway control function of this master gatekeeper, and a gateway performing protocol conversion for communicating with other zones. 
     Owing to the above configuration, the gateway system handles an address translation request in the proxy gatekeeper to reduce the load of the master gatekeeper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other objects, features and advantages of this invention will become more apparent by reference to the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a block diagram of a gateway system according to the present invention; 
         FIG. 2  is a functional block diagram of an H.323 gatekeeper; 
         FIG. 3  is an explanatory diagram of transmission and reception between a gateway and an endpoint; 
         FIG. 4  is another explanatory diagram of transmission and reception between a gateway and an endpoint; 
         FIG. 5  is a functional block diagram of another H.323 gatekeeper; 
         FIG. 6  is still another explanatory diagram of transmission and reception between a gateway and an endpoint; and 
         FIG. 7  is a further explanatory diagram of transmission and reception between a gateway and an endpoint. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Next, embodiments of the present invention will be described with reference to drawings. 
       FIG. 1  shows a configuration of the present invention, and this embodiment includes a master gatekeeper  1 , a gateway apparatus  2 , and a network address &amp; port number translator  3 . The gateway apparatus  2  comprises a proxy gatekeeper  21 , and a gateway  22 . The master gatekeeper  1  and gateway apparatus  2  form a zone  6  described in the H.323 specification, and the zone  6  communicates with a gatekeeper  4  and an endpoint  5  in another zone  7  via the network address &amp; port number translator  3 . 
     The gateway apparatus  2  comprises the gateway  22  and proxy gatekeeper  21 . The proxy gatekeeper  21  has an address translation function and a zone management function that are similar to those of the master gatekeeper  1 . The gateway  22  performs protocol conversion for the communication of the zone  6  with another zone  7 . 
     As shown in  FIG. 2 , the functions of a conventional gatekeeper  8  is functionally dispersed in the master gatekeeper  1  and proxy gatekeeper  21 . The proxy gatekeeper  21  has an address translation function  21   a  and a zone management function  21   b  out of the gateway control function that the conventional H.323 gatekeeper  8  has for processing, so as to resolve a bottleneck due to access convergence from gateways. The master gatekeeper  1  has an admission control function  1   e , a bandwidth control function id, a call control signaling-function  1   e , a call authorization function  1   f , a band width management function  1   g , and a call management function  1   h  besides an address translation function  1   a  and a zone management function  1   b.    
     The network address &amp; port number translator  3  has a function for mutually translating network addresses and port numbers when any one of the master gatekeeper  1 , proxy gatekeeper  21 , and gateway  22  communicates with another zone  7 . A port number is an address in a transport layer. In particular, by translating a network address and a port number of the master gatekeeper  1  into a network address and a port number of the proxy gatekeeper  21 , the proxy gatekeeper  21  seems from the gatekeeper  4  and endpoint  5  of another zone  7  to be a gatekeeper of the zone  6  instead of the master gatekeeper  1 . 
     The gateway  22  has a function for again requesting an admissions request to a call, which was rejected by an admissions rejection from the proxy gatekeeper  21 , of the master gatekeeper  1  in addition to the conventional H.323 gateway function. 
     Next, the operation of this embodiment will be described with reference to  FIGS. 1 ,  3 , and  4  in detail. 
     In  FIG. 3 , when transmitting a signal to the endpoint  5 , the gateway  22  transmits an admissions request A 1  to the proxy gatekeeper  21 . The proxy gatekeeper  21  transmits location request A 2  to the gatekeeper  4  of another zone  7  by the address translation function, and acquires a transport address for signaling the endpoint  5  from the response of location confirm A 3 . The proxy gatekeeper  21  transmits admission confirm A 4  to the gateway  22  if acknowledging the admission request A 1 . The gateway  22  opens a signaling channel A 5  to a transport address designated in the admission confirm A 4 . 
     On the other hand, in  FIG. 4 , if the gateway  22  transmits an admissions request B 1 , requesting a function that the proxy gatekeeper  21  does not have, the proxy gatekeeper  21  transmits location request B 2  to the gatekeeper  4  of another zone  7  by the address translation function. If the proxy gatekeeper  21  acquires a transport address for signaling the endpoint  5  from the response of location confirm B 3 , the proxy gatekeeper  21  transmits admission reject B 4 . The gateway  22  receiving the admission reject B 4  transmits an admissions request B 5  to the master gatekeeper  1 . The master gatekeeper  1  transmits an admissions confirm B 6  to the gateway  22  if acknowledging the admission request. The gateway  22  opens a signaling channel B 7  to a transport address designated in the admission confirm B 6 . 
     Next, the operation of this embodiment will be described by using a concrete example. For example, in  FIG. 3 , if transmitting a signal to an alias address of the endpoint  5 , “012-345-6789”, the gateway  22  first transmits the admission request A 1 , sent to this alias address “012-345-6789”, to the proxy gatekeeper  21 . The proxy gatekeeper  21  transmits the location request A 2  to the gatekeeper  4  containing this alias address of the endpoint  5 , “012-345-6789”, and acquires a transport address “10.1.2.3:1720” for the endpoint  5  from the response of the location confirm A 3 . After that, the proxy gatekeeper  21  transmits the admission confirm A 4 , including the transport address “10.1.2.3:1720” for the endpoint  5 , to the gateway  22 . The gateway  22  opens the signaling channel A 5  to the transport address “10.1.2.3:1720” designated. 
     In addition, in  FIG. 4 , when transmitting the admission request B 1 , including user authentication, to the proxy gatekeeper  21 , the proxy gatekeeper  21  transmits the admission reject B 4  since it does not having a authentication function. The gateway  22  receiving the admission reject again transmits the admission request B 5  to the master gatekeeper  1 . The master gatekeeper  1  transmits the admission confirm B 6  to the gateway  22  if the user authentication is successful and the master gatekeeper  1  acknowledges the admission request. The gateway  22  opens the signaling channel B 7  to a transport address designated in the admission confirm B 6 . 
     Next, another embodiment of the present invention will be described. 
     In  FIG. 5 , this embodiment is different at the point of having a call control signaling-function  21   e  in addition to the address translation function  21   a  and zone management function  21   b  in the embodiment shown in  FIG. 2 . Owing to that, a signaling channel between the gateway  22  and endpoint  5  is not directly opened by the judgment of the proxy gatekeeper  21  as shown in  FIG. 6 . Nevertheless, a signaling channel C 5  between the gateway  22  and proxy gatekeeper  21  and a signaling channel C 6  between the proxy gatekeeper  21  and endpoint  5  are opened. 
     In addition, with referring to  FIG. 7 , this embodiment is different at the point of giving the information of a transport address for signaling the master gatekeeper  1  instead of the transport address for signaling the endpoint  5  in the admission confirm D 6  the information of which the master gatekeeper  1  gives to the gateway  22 . Owing to this, the signaling channel between the gateway  22  and endpoint  5  is not directly opened. Nevertheless, a signaling channel D 7  between the gateway  22  and master gatekeeper  1  and a signaling channel D 8  between the master gatekeeper  1  and endpoint  5  are opened. 
     The network address &amp; port number translator  3  mutually translates a network address and a port number of the master gatekeeper  1  and a network address and a port number of the proxy gatekeeper  21  every time a signal transmitted or received on the signaling channel D 8  passes the network address &amp; port number translator  3 . In consequence, the signaling channel D 8  seems from the endpoint  5  to be a signaling channel D 9  opened between the endpoint  5  and proxy gatekeeper  21 . 
     Next, a concrete example will be described. For example, in  FIG. 6 , if the gateway  22  transmits a signal to an alias address of the endpoint  5 , “012-345-6789”, the gateway  22  first transmits an admissions request C 1 , requesting the participation in this alias address “012-345-6789”, to the proxy gatekeeper  21 . The proxy gatekeeper  21  transmits location request C 2  to the gatekeeper  4 , containing this alias address of the endpoint  5 , “012-345-6789”, to acquire a transport address of the endpoint  5 , “10.1.2.3:1720” from the response of location confirm C 3 . After that, the proxy gatekeeper  21  transmits admission confirm C 4 , including the transport address “10.4.5.6:1720” of the proxy gatekeeper itself instead of the transport address for the endpoint  5 , to the gateway  22 . The gateway  22  opens the signaling channel C 5  to the transport address “10.4.5.6:1720” designated. 
     Furthermore, the proxy gatekeeper  21  opens the signaling channel C 6  to the transport address “10.1.2.3:1720” for the endpoint  5 . The signaling channels C 5  and C 6  forms a signaling channel between the gateway  22  and endpoint  5 . 
     In addition, in  FIG. 7 , if the gateway  22  transmits a signal to the alias address of the endpoint  5 , “012-345-6789”, procedure from an admissions request D 1  to an admissions request D 5  is similar to the procedure from the admission request B 1  to the admission request B 5  in  FIG. 4 . The master gatekeeper  1  transmits an admission confirm D 6 , including the transport address of “10.4.5.6:1720” of the master gatekeeper  1  itself, instead of the transport address “10.1.2.3:1720” for the endpoint  5 , to the gateway  22  at the step of the admission. The gateway  22  opens the signaling channel D 7  to the transport address “10.4.5.7:1720” designated. Furthermore, the master gatekeeper  1  opens a signaling channel D 8  to the transport address of the endpoint  5 , “10.1.2.3:1720”. The signaling channels D 7  and D 8  forms a signaling channel between the gateway  22  and endpoint  5 . 
     Here, the network address &amp; port number translator  3  mutually translator a network address and a port number of the master gatekeeper  1 , which are included in a signal sent from the master gatekeeper  1  to the endpoint  5 , into a network address and a port number of the proxy gatekeeper  21  when the network address and port number of the master gatekeeper  1  pass the network address &amp; port number translator  3 . On the contrary, the network address &amp; port number translator  3  mutually translator a network address and a port number of the proxy gatekeeper  21 , which are included in a signal sent from the endpoint  5  to the master gatekeeper  1 , into a network address and a port number of the master gatekeeper  1  when the network address and port number of the proxy gatekeeper  21  pass the network address &amp; port number translator  3 . Therefore, the signaling channel D 8  seems from the endpoint  5  to be the signaling channel D 9  opened between the endpoint  5  and proxy gatekeeper  21 . 
     As described above, if transmitting a signal to the endpoint  5 , the gateway  22  performs an admissions request, requesting the participation to the H.323 communication, to the proxy gatekeeper  21 . The proxy gatekeeper  21  acquires an addressee&#39;s address of the endpoint  5  by the address translation function. Then, the proxy gatekeeper  21  gives the information, including the addressee&#39;s address in admissions confirm, to the gateway  22  if admission request is acceptable. If not, the proxy gatekeeper  21  informs the gateway  22  of admissions reject, including the addressee&#39;s address. 
     The gateway  22  again performs an admissions request, requesting the participation in the H.323 communication, to the master gatekeeper  1  if the participation is negatively acknowledged. The master gatekeeper  1  judges whether the admissions request of the gateway  22  is acceptable. The master gatekeeper  1  informs the gateway  22  of the admissions confirm or admissions reject. After receiving the admissions confirm from the proxy gatekeeper  21  or master gatekeeper  1 , the gateway  22  opens a signaling channel between the gateway  22  and endpoint  5  to perform the subsequent H.323 procedure. 
     Owing to this, it becomes possible to handle more gateways than gateways that one conventional gatekeeper can handle. 
     As described above, the present invention handles an address translation request of a gateway with a proxy gatekeeper inside a gateway apparatus to reduce the load of a master gatekeeper. Therefore, it is possible to handle more gateways than gateways that one conventional gatekeeper can handle. In consequence, it becomes unnecessary to increase the processing capability of a gatekeeper or add a gatekeeper as a number of gateways is increased. 
     In addition, it is possible to reduce the processing wait time of a gateway, which is necessary only for address translation, by processing an address translation request of a gateway with a proxy gatekeeper inside a gateway apparatus.