JP2015226114A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance capability of a media communication function having a large processing load without adding a session control function, and further to achieve a load distribution configuration with a high degree of freedom.SOLUTION: An SS having received a request requests any one RS to pay out a private IP address of the RS and a reception port number, and receives the payout (S3). The SS sends an L7SW a SIP signal (INVITE) including an IP header in which the private IP address of itself is set, a SIP header in which a designated line number and the private IP address of itself are set, and SDP information in which the paid-out private IP address and the paid-out reception port number (RS side reception port) are set.

Description

  The present invention relates to a communication system.

  A media server used for interactive communication with a user using voice, image, etc. generally has a session control function by SIP (Session Initiation Protocol) and a media communication function by RTP (Realtime Transport Protocol). The external interface is also shared by SIP and RTP.

  Since the media server communicates simultaneously with an unspecified number of users, more channels and higher processing performance are required than user terminals, and the number of servers is increased or decreased according to traffic. Since RTP generally has a higher processing load than SIP, in many cases, the required number of servers is determined by the amount of media communication processing.

JP2012-244392A

  In a conventional media server in which the session control function and the media communication function are housed in a single chassis, even if the media communication function alone is insufficient in processing capacity, it must be added together with the session control function. The processing capability of the expandable media communication function is limited. In addition, since the server that performed session control also performs media communication as it is, variations in server selection in load distribution are not so large.

  On the other hand, when multiple UNI lines are connected to the system and SIP packets and RTP packets share the same line, the line to be used is selected by setting the corresponding telephone number in the SIP header for each communication. However, if a part of the line becomes unusable due to a failure, it is required to quickly remove the line from the selection. For this purpose, it is necessary to change the SIP settings. However, if the session control function and the media control function are integrated, the settings of all media servers must be changed.

  An object of the present invention is to enhance the capability of a media communication function with a large processing load without adding a session control function, and to realize a load distribution configuration with a high degree of freedom.

  In order to solve the above problems, a first aspect of the present invention is a communication system including a SIP server, an RTP server, and a layer 7 switch, wherein the layer 7 switch has a global IP address for each of a plurality of connected lines. The SIP server requests the layer 7 switch to select an RTP server, and requests the RTP server selected by the layer 7 switch to issue a private IP address and a receiving port number of the RTP server. The SIP request signal received from the RTP server and including the private IP address and reception port number of the RTP server and the private IP address of the SIP server is transmitted to the layer 7 switch, and the layer 7 switch Each private IP address included in the Replace with the global IP address corresponding to one line, replace the reception port number set in the signal with the paid-out reception port number and send it to the line, and the layer 7 switch receives the SIP response signal received from the line The global IP address of the layer 7 switch corresponding to the line set in the above is replaced with the private IP address of the SIP server and transmitted to the SIP server, and the SIP server sends the received port number to the RTP server The network-side receiving port number and network-side global IP address for communication through the line set in the SIP response signal received from the layer 7 switch are notified, and the RTP server is notified from the SIP server. Network side network that communicates through the connected line. RTP signals in which the IP address and the receiving port number are set as the destination IP address and the destination port number, respectively, and the private address of the RTP server and the receiving port number issued by the RTP server are set as the source IP address and the source port number, respectively. To the layer 7 switch, and the layer 7 switch sets the source IP address and source port number of the RTP signal to the global IP address corresponding to the line and the reception port number issued by the layer 7 switch, respectively. Replaced and sent to the line, and the layer 7 switch issued a global IP header corresponding to the line that is the destination IP address of the RTP signal received from the line and the layer 7 switch that is the destination port number The reception port number is replaced with the private address of the RTP server and the reception port number assigned by the RTP server, respectively, and transmitted to the RTP server.

  A second aspect of the present invention is a communication system including an SIP server, an RTP server, and a layer 7 switch, wherein the layer 7 switch has a global IP address for each of a plurality of connected lines, and the layer 7 switch , A SIP request signal including a reception port number and replaces the global IP address of the SIP request signal received from any of the lines with the private IP address of the SIP server, and transmits the SIP server to the SIP server. The layer 7 switch is requested to select an RTP server, the RTP server selected by the layer 7 switch is requested to issue a private IP address and a receiving port number of the RTP server, and the RTP server is issued. Private IP address and reception of the RTP server The network side that transmits the SIP response signal in which the port number and the private IP address of the SIP server are set to the layer 7 switch and communicates with the RTP server through the line set in the SIP request signal The layer 7 switch sends the private IP address included in the SIP response signal to the global IP address corresponding to the line that received the SIP request signal. Replace the received port number, replace the received port number set by the RTP server in the SIP response signal with the received port number set by the layer 7 switch, and send it to the line. The RTP server Through the line notified from the SIP server. The global IP address and reception port number on the network side that performs the transmission are set as the destination IP address and destination port number, respectively, and the private address of the RTP server and the reception port number issued by the RTP server are the transmission source IP address and the transmission source port number, respectively. The RTP signal set as is transmitted to the layer 7 switch, and the layer 7 switch sends out the source IP address and source port number of the RTP signal by the global IP address corresponding to the line and the layer 7 switch, respectively. The layer 7 switch replaces the received port number with the received port number and sends it to the line. The reception port number issued by the switch is replaced with the private address of the RTP server and the reception port number issued by the RTP server, respectively, and transmitted to the RTP server.

  According to the present invention, the capability of a media communication function with a large processing load can be enhanced without adding a session control function, and a load distribution configuration with a high degree of freedom can be realized.

1 shows a schematic diagram of a communication system according to an embodiment of the present invention. A procedure for receiving a call from the application server AS to the terminal via the media server and the L7SW will be described. The supplementary explanation about the procedure of FIG. 2 is shown. A procedure for receiving an incoming call from the terminal to the RS will be described. When a SIP signal (INVITE) is transmitted from either SS # 1 or SS # 2 to either L # 1 or L # 2 via L7SW, how the SIP signal is rewritten Show.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic diagram of a communication system according to an embodiment of the present invention.

  The media server is physically separated into SIP servers SS # 1, SS # 2 having a session control function and RTP servers RS # 1, RS # 2, RS # 3, RS # 4 having a media communication function. It is configured. The numbers of SIP servers and RTP servers are shown for convenience and are not limited to this.

  The association between the SIP server and the RTP server is performed by the layer 7 switch L7SW that accommodates these and terminates the UNI lines L # 1, L # 2, and L # 3. The UNI line is accommodated in the IP network and is used for transmission and reception of SIP signals and RTP signals. The number of UNI lines is shown for convenience and is not limited to this.

  For example, if the UNI line L # 2 fails during operation, switching to the spare UNI line L # 3 is performed.

Hereinafter, the SIP server, RTP server, layer 7 switch, and UNI line are referred to by reference numerals. The same applies to an application server AS described later. In addition, when only one SIP server is called, it is called SS. In addition, when only one RTP server is called, it is called RS.
(L7SW)
In addition to the load distribution function, the L7SW performs global IP address selection based on the line number, NAT (Network Address Translation) conversion, ALG (Application Level Gateway) conversion, and DSCP conversion for the SIP signal.

  The L7SW performs NAT conversion and DSCP conversion of the IP header based on the global IP address for the RTP signal.

  The L7SW has a global IP address that corresponds one-to-one with the UNI line.

  The reception port number is associated with the UNI line side and the RTP server side.

  Further, when the L7SW receives a SIP signal (INVITE) (also referred to as a SIP request signal) from the UNI line side, the L7SW selects a SIP server by a round robin method and transmits / receives the SIP signal to / from the SIP server.

The L7SW selects an RTP server based on the received reception port number and IP address, and transmits / receives an RTP signal.
(SS # 1, SS # 2)
SS # 1 and SS # 2 (SIP server) perform transmission / reception of SIP signals, selection of line numbers, requests for reception port numbers, IP addresses, and settings for SDP information.
(RS # 1 to RS # 4)
RS # 1 to RS # 4 (RTP server) perform transmission / reception of RTP signals and delivery of reception port numbers / IP addresses.

  The SIP server and the RTP server exchange the reception port number / IP address.

  With reference to FIG. 2, a description will be given of a procedure in the case of receiving an incoming call from the application server AS to the terminal via the media server and the L7SW.

  As described above, the L7SW has the same number of global IP addresses as the UNI line, and a global IP address is assigned to each UNI line on a one-to-one basis. Further, it is assumed that the calling number and the global IP address have a one-to-one correspondence.

  (S1) The AS designates the called-side line number (for example, 042259XXX) to any one SS and requests the generation of the SIP signal (invite Participant (To: 042259XXXX)).

  (S2) Upon receiving the request, the SS requests the L7SW to select, and requests any one RS selected by the L7SW to issue the private IP address and receiving port number (RS side receiving port) of the RS. And receive a private IP address and receiving port number.

  (S3) The SS has an IP header in which its own private IP address is set, a SIP header in which a designated line number and its own private IP address are set, an assigned private IP address and an assigned receiving port number ( The SIP signal (INVITE) including the SDP information in which the RS side reception port) is set is transmitted to the L7SW.

  The L7SW replaces each private IP address set in the IP header, SIP header, and SDP information with a global IP address corresponding to the line number, pays out the terminal-side reception port number (terminal-side reception port), and generates SDP information. The reception port number set in (1) is replaced with the paid-out reception port number, and a SIP signal (INVITE) is transmitted to the UNI line corresponding to the line number.

  A terminal connected to the UNI line receives a SIP signal (INVITE).

  Further, the L7SW receives the SIP signal (200 OK) (also referred to as SIP response signal) from the terminal via the UNI line, and the global IP address of the L7SW corresponding to the line set in the response signal is changed to the SIP signal. Replace (INVITE) with the private IP address of the SIP server that has transmitted (INVITE), and transmit to the SIP server. This SIP signal (200 OK) includes a reception port number on the network side for performing communication through the UNI line and a global IP address on the network side.

  (S4) This SS receives the SIP signal (200 OK), and for the RS that has issued the reception port number, the network-side reception port number and global IP address set in the signal for communication through the UNI line And request a connection.

  (S5) The RS and the terminal start communication with the RTP signal. The RS side reception port corresponds to the reception port number assigned by the RS, and the terminal side reception port corresponds to the reception port number assigned by the L7SW.

  Specifically, the RS uses the global IP address and reception port number of the network side that communicates through the line, notified from the SS, as the destination IP address and destination port number, respectively, and the private address of the RS and the reception that the RS has issued. An RTP signal in which the port number is set as the transmission source IP address and the transmission source port number is transmitted to the L7SW.

  The L7SW replaces the transmission source IP address and transmission source port number of the RTP signal with the global IP address corresponding to the line and the reception port number assigned by the layer 7 switch, respectively, and transmits the result to the line.

  L7SW issued the private IP address of RS and RS received the received port number issued by the layer 7 switch, which is the global IP header corresponding to the line that is the destination IP address of the RTP signal received from the line, and the destination port number. Replace with the reception port number and send to RS.

  (S6) On the other hand, the SS issues an event indicating that the RS and the terminal are communicating to the AS (notifySessionEvent (during communication)).

  As shown in FIG. 3, after SS # 1 and SS # 2 (SS) are designated by AS as the destination line number (042259XXXX) and received payout from RS # 1 and RS # 2 (hereinafter referred to as RS) In the SIP signal (INVITE) transmitted to the L7SW, the IP header includes an SS private IP address (Source: private IP address (SS)) and IP network identification information (Destination: NGN-IP).

  The SIP header includes an AS line number (From / PA-ID: 043211XXXX), a called line number (R-URI / To: 042259XXX), and an SS private IP address (Contact / Via: Private IP). Address (SS)).

  The SDP information includes a reception port number issued by the RS (reception port: RS issue number) and a private IP address (c = / o = line: private IP address (RS)) issued by the RS.

  As shown in FIG. 3, the IP header of the SIP signal (INVITE) sent from the L7SW to the UNI line by the rewriting of the IP layer header (NAT operation) of the SIP signal (INVITE) in the L7SW corresponds to the UNI line. The global IP address (Source: global IP address) of the L7SW and the DSCP value (for example, DSCP: 0x2e) are included.

  Further, by rewriting the SIP header / SDP information of the SIP signal in the L7SW (ALG operation), the SIP header of the SIP signal (INVITE) sent from the L7SW to the UNI line includes the global IP address of the L7SW corresponding to the UNI line ( Contact / Via: global IP address) and the reception port number issued by the L7SW (reception port: L7SW issue number) are included. The SDP information includes the global IP address (c = / o = line: global IP address) of the L7SW corresponding to the UNI line.

  Further, as shown in FIG. 3, in the RTP signal from the RS to the L7SW, the IP header includes an RS private IP address (Source: private IP address (RS)) and IP network identification information (Destination: NGN- IP).

  Also, as shown in FIG. 3, by rewriting the IP layer header of the RTP signal in the L7SW (NAT operation), in the RTP signal to the terminal, the IP header includes the global IP address (Source: L7SW) corresponding to the UNI line. Global IP address) and a DSCP value (eg, DSCP: 0x2e).

  Next, with reference to FIG. 4, the procedure for receiving an incoming call from the terminal to the RS will be described.

  (T1) The L7SW receives the SIP signal (INVITE) from any terminal via the UNI line. The SIP signal (200 OK) includes a reception port number on the network side that performs communication through the UNI line and a global IP address on the network side.

  (T2) The L7SW selects any one SS by the round robin method, and uses the global IP address of the L7SW set in the IP header, SIP header, and SDP information of the SIP signal (200 OK) as the private IP address of the SS. And the replaced SIP signal (INVITE) is transmitted.

  (T3) Upon receiving the SIP signal (INVITE), the SS requests the L7SW to select an RS, and for one RS selected by the L7SW, corresponds to the RS private IP address and the reception port number (corresponding to the RS side reception port) (Receiving port number) is requested and the private IP address and receiving port number are received.

  The SS is a SIP signal (200 OK) including an IP header in which its own private IP address is set, a SIP header in which the private IP address is set, and an SDP information in which the assigned private IP address and the received reception port number are set. ) (Response signal) is transmitted to L7SW.

  In addition, the SS notifies the RS of the reception port number on the network side and the global IP address on the network side that are set in the SIP signal (200 OK) for communication through the UNI line.

  (T4) The L7SW that has received the SIP signal (200 OK) corresponds each private IP address set in the IP header, SIP header, and SDP information to the UNI line (UNI line that has received the SIP signal (INVITE)). Replace with the global IP address of the L7SW, pay out the reception port number, replace the reception port number assigned by the RS set in the SDP information with the reception port number issued by the L7SW, and send it to the UNI line.

  The RS and the terminal start communication with the RTP signal.

  (T5) At this time, the L7SW selects an RS according to the paid-out receiving port number and the paid-out private IP address, and transmits an RTP signal to this RS.

  Specifically, the RS uses the global IP address and reception port number of the network side that communicates through the line, notified from the SS, as the destination IP address and destination port number, respectively, and the private address of the RS and the reception that the RS has issued. An RTP signal in which the port number is set as the transmission source IP address and the transmission source port number is transmitted to the L7SW.

  The L7SW replaces the transmission source IP address and transmission source port number of the RTP signal with the global IP address corresponding to the line and the reception port number assigned by the layer 7 switch, respectively, and transmits the result to the line.

  L7SW issued the private IP address of RS and RS received the received port number issued by the layer 7 switch, which is the global IP header corresponding to the line that is the destination IP address of the RTP signal received from the line, and the destination port number. Replace with the reception port number and send to RS.

Referring to FIG. 5, when a SIP signal (INVITE) is transmitted from either SS # 1 or SS # 2 to either L # 1 or L # 2 via L7SW, the SIP signal is Explain how it is rewritten.
(1)
In the SIP signal (INVITE) transmitted to L7SW after SS # 1 is assigned the line number of L # 1 from AS and receives payout from RS # 1,
The IP header includes the private IP address of SS # 1 (Source: private IP address SS # 1).

  The SIP header includes the L # 1 line number (From / PA-ID: line # 1 number) and the SS # 1 private IP address (Contact / Via: private IP address SS # 1).

  Note that the From / PAA-ID line number is preferably not fixed to the SS unit for load distribution.

  The SDP information includes the private IP address of RS # 1 (c = / o = line: private IP address RS # 1) and the port number received from RS # 1 (reception port number: # 1). .

In the SIP signal (INVITE) sent from L7SW to L # 1 that has received this SIP signal (INVITE),
The IP header includes the L7SW global IP address (Source: global IP address # 1) corresponding to L # 1.

  The SIP header includes the L # 1 line number (From / PA-ID: line # 1 number) and the L7SW global IP address (Contact / Via: global IP address # 1) corresponding to L # 1. included.

The SDP information includes the global IP address of the L7SW corresponding to L # 1 (c = / o = line: global IP address # 1) and the port number (reception port number: #A or #B) issued by the L7SW. included.
(2)
In the SIP signal (INVITE) transmitted to L7SW after SS # 1 is assigned the line number of L # 2 from AS and receives payout from RS # 1,
The IP header includes the private IP address of SS # 1 (Source: private IP address SS # 1).

  The SIP header includes a line number (From / PA-ID: line # 2 number) and a private IP address of SS # 1 (Contact / Via: private IP address SS # 1).

  The SDP information includes the private IP address of RS # 1 (c = / o = line: private IP address RS # 1) and the port number received from RS # 1 (reception port number: # 2). .

In the SIP signal (INVITE) sent from L7SW to L # 2 that has received this SIP signal (INVITE),
The IP header includes the L7SW global IP address (Source: global IP address # 2) corresponding to L # 2.

  The SIP header includes the L # 2 line number (From / PA-ID: line # 2 number) and the L7SW global IP address (Contact / Via: global IP address # 2) corresponding to L # 2. included.

The SDP information includes the global IP address of the L7SW corresponding to L # 2 (c = / o = line: global IP address # 2) and the port number (reception port number: #A or #B) issued by the L7SW. included.
(3)
In the SIP signal (INVITE) transmitted to L7SW after SS # 2 is assigned the line number of L # 1 from AS and receives payout from RS # 2.
The IP header includes an SS # 2 private IP address (Source: private IP address SS # 2).

  The SIP header includes the L # 1 line number (From / PA-ID: line # 1 number) and the SS # 2 private IP address (Contact / Via: private IP address SS # 2).

  The SDP information includes the private IP address of RS # 2 (c = / o = line: private IP address RS # 2) and the port number received from RS # 2 (reception port number: # 1). .

The SIP signal (INVITE) sent from L7SW to L # 1 that has received this SIP signal (INVITE) is the same as in the case of (1) above.
(4)
In the SIP signal (INVITE) transmitted to L7SW after SS # 2 is assigned the line number of L # 2 from AS and receives a payout from RS # 2,
The IP header includes an SS # 2 private IP address (Source: private IP address SS # 2).

  The SIP header includes the L # 2 line number (From / PA-ID: line # 2 number) and the SS # 2 private IP address (Contact / Via: private IP address SS # 2).

  The SDP information includes the private IP address of RS # 2 (c = / o = line: private IP address RS # 2) and the port number received from RS # 2 (reception port number: # 2). .

  The SIP signal (INVITE) sent from L7SW to L # 2 that has received this SIP signal (INVITE) is the same as in the case of (2) above.

  As described above, according to the communication system of the present embodiment, when it is desired to increase the capability of the media communication function with a large processing load, it is only necessary to increase the RTP server, and accordingly, it is necessary to increase the SIP server. Absent. Therefore, the media communication function can be enhanced without increasing the session control function. Furthermore, by making the correspondence between the session control function and the media communication function non-fixed, a highly flexible load distribution configuration can be realized.

SS # 1, SS # 2 SIP server RS # 1, RS # 2, RS # 3, RS # 4 RTP server L7SW Layer 7 switch AS Application server

Claims (2)

A communication system including a SIP server, an RTP server, and a layer 7 switch,
The layer 7 switch has a global IP address for each of a plurality of connected lines,
The SIP server requests the layer 7 switch to select an RTP server, requests the RTP server selected by the layer 7 switch to issue a private IP address and a reception port number of the RTP server, and The SIP request signal received from the private IP address and reception port number of the RTP server and the private IP address of the SIP server is transmitted to the layer 7 switch.
The layer 7 switch replaces each private IP address included in the SIP request signal with a global IP address corresponding to one line, and replaces the reception port number set in the signal with the issued reception port number. , Send to the line,
The layer 7 switch replaces the global IP address of the layer 7 switch corresponding to the line set in the SIP response signal received from the line with the private IP address of the SIP server, and transmits the SIP server to the SIP server.
The SIP server sets a reception port number on the network side and a global IP address on the network side, which are set in the SIP response signal received from the layer 7 switch, to the RTP server that has issued the reception port number. Inform the address,
The RTP server uses a network-side global IP address and reception port number for communication through the line notified from the SIP server as a destination IP address and a destination port number, respectively, and the private address of the RTP server and the RTP server RTP signals set with the received reception port numbers as the transmission source IP address and transmission source port number are transmitted to the layer 7 switch;
The layer 7 switch replaces the source IP address and source port number of the RTP signal with the global IP address corresponding to the line and the reception port number assigned by the layer 7 switch, respectively, and sends it to the line.
The layer 7 switch sets the global IP header corresponding to the line that is the destination IP address of the RTP signal received from the line and the reception port number that is issued by the layer 7 switch that is the destination port number, respectively. A communication system, wherein the address and the reception port number assigned by the RTP server are replaced and transmitted to the RTP server. A communication system including a SIP server, an RTP server, and a layer 7 switch,
The layer 7 switch has a global IP address for each of a plurality of connected lines,
The layer 7 switch replaces the global IP address of the SIP request signal including the reception port number received from any of the lines with the private IP address of the SIP server, and transmits the SIP request signal to the SIP server.
The SIP server requests the layer 7 switch to select an RTP server, requests the RTP server selected by the layer 7 switch to issue a private IP address and a reception port number of the RTP server, and A SIP response signal in which the private IP address and receiving port number of the RTP server issued from the server and the private IP address of the SIP server are set is transmitted to the layer 7 switch, and the SIP request signal is transmitted to the RTP server. The network-side receiving port number and the network-side global IP address for communication through the line set to
The layer 7 switch replaces each private IP address included in the SIP response signal with a global IP address corresponding to the line that has received the SIP request signal, pays out a reception port number, and is set in the SIP response signal. Further, the reception port number assigned by the RTP server is replaced with the reception port number assigned by the layer 7 switch, and sent to the line.
The RTP server uses a network-side global IP address and reception port number for communication through the line notified from the SIP server as a destination IP address and a destination port number, respectively, and the private address of the RTP server and the RTP server RTP signals set with the received reception port numbers as the transmission source IP address and transmission source port number are transmitted to the layer 7 switch;
The layer 7 switch replaces the source IP address and source port number of the RTP signal with the global IP address corresponding to the line and the reception port number assigned by the layer 7 switch, respectively, and sends it to the line.
The layer 7 switch sets the global IP header corresponding to the line that is the destination IP address of the RTP signal received from the line and the reception port number that is issued by the layer 7 switch that is the destination port number, respectively. A communication system, wherein the address and the reception port number assigned by the RTP server are replaced and transmitted to the RTP server.

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