CA2340293C

Terminal-to-terminal communication connection control method using ip transfer network

Abstract

A terminal-to-terminal communication connection control method that can be applied to multimedia communication in which a connection server and a relay connection server are installed in an IP transfer network. A telephone set and a terminal such as an IP terminal and a video terminal transport an initial address message, an address completion message, a call pass message, an answer message, a release message, a release completion message, which can be made in 1-to-1 correspondence with line connection control messages of a common line signal system. Furthermore, while an address administration table is set to a network node apparatus of an IP transfer network, means for registering addresses of the terminals into this address administration table is employed, so that an IP packet communication by a multicast can be realized with improved information security performance.

CA2340293C, drawing sheet 1
Sheet 1 of 150

Term

Term ended

Expired 8 March 2021, 5.5 years ago.

  1. Priority
  2. Filed
  3. Granted
  4. Expired
  5. Today

19 claims: 15 independent, 4 dependent

  1. 1
    CA 02340293 2007-08-17 The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:1. A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein : said IP transfer network includes plural network node apparatus, plural connection servers, plural proxy connection servers and a domain name server, plural terminals are connected to said IP transfer network, a terminal Tl is connected to a network node apparatus Nl by a logical terminal LPl via a communication line Ll, a terminal T2 is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, and said domain name server holds a set of a telephone number or host name TNj (j=l,2,3, ... ) of a terminal Tj, an internal IP address IAj being a discrimination information of a logical terminal LPj and an internal IP address k of a connection server Sk carrying out a connection control of said terminal Tj, an IP communication record R81 including a discrimination information of said logical terminal LPl is set in said network node apparatus Nl, and an IP communication record R82 including a discrimination information of said logical terminal LP2 is set in said network node apparatus N2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2, wherein said external IP packet 1 includes a connection request and said telephone numbers or host names TNI andTN2 and a destination address thereof is an external IP address EA81 of a proxy connection server PSl, 513 CA 02340293 2007-08-17 said network node apparatus N1 inspects an IP capsulation condition to be satisfied by an external IP address in said external IP packet 1 according to a rule of said IP communication record R81, said external IP packet 1 which said IP capsulation condition is not satisfied is discarded, when said IP capsulation condition is satisfied, said network node apparatus N1 forms a first type internal IP packet 11 by capsulating said external IP packet 1 and sends it, a destination address of said internal IP packet 11 is an internal IP address IA81 of said proxy connection server PSI, said proxy connection server PSI converts said internal IP packet 11 into a second type internal IP packet 12 and sends it to a connection server SI, said connection server SI obtains said telephone numbers or host names TNI and TN2 and said external IP address EAl from said internal IP packet 12, and further obtains an external IP address EA2 of said terminal T2, an internal IP address IA2 being a discrimination information of said logical terminal LP2 and an internal IP address IA92 of said connection server S2 carrying out a connection control of said terminal T2 by presenting said telephone number or host name TN2 of said destination terminal T2 to a domain name server DS1, said connection server SI sends an initial address message (IAM)including said connection request to said connection server S2, said connection server S2 obtains said telephone numbers or host names TNI and TN2, said external IP address EAl and EA2 and said internal IP address IA1 and IA2 from said initial address message (IAM), said connection server S2 sends a second type internal IP packet 21 including a receipt notification, said internal IP packet 21 is converted into a first type 514 CA 02340293 2007-08-17 internal IP packet 22 by a proxy connection server PS2, said internal IP packet 22 is converted into an external IP packet 2 including said receipt notification at said network node apparatus N2, said external IP packet 2 reaches at said terminal T2, and said connection server S2 forms an address completion message (ACM) including a receipt propriety notification and sends it to said connection server SI, said terminal T2 transmits an external IP packet 3 that includes a call-on notification for notifying a response preparation start and a destination address thereof is an external IP address EA82 of a proxy connection server PS2, an external IP address of said external IP packet 3 is judged at said network node apparatus N2 according to an IP capsulation condition defined by said IP communication record R82, said external IP address becomes to a first type internal IP packet 31 including said call-on notification, and then becomes to a second type internal IP packet 32 and reaches at said connection server S2, said connection server S2 forms a call progress message (CPG) including said call-on notification and sends it to said connection server SI, said connection server SI sends a second type internal IP packet 41 including said call-on notification, said internal IP packet 41 becomes to a first type internal IP packet 42 and becomes to an external IP packet 4 including said call-on notification at said network node apparatus Nl, and said external IP packet 4 reaches at said terminal Tl, said terminal T2 transmits an external IP packet 5 including a response notification for notifying a response and a port number PN2 of said terminal T2, an IP capsulation condition of said external IP packet 5 is 515 CA 02340293 2007-08-17 judged at said network node apparatus N2 and becomes to a first type internal IP packet 51 including said response notification, said internal IP packet 51 becomes to a second type internal IP packet 52 and reaches at said connection server S2, said connection server S2 forms a response message (ANM) including said response notification and said port number PN2 and sends it to said connection server SI, said connection server Si sends a second type internal IP packet 61 including said response notification, an external IP address EA2 of said terminal T2 and said port number PN2, said internal IP packet 61 becomes a first type internal IP packet 62, said internal IP packet 62 becomes to an external IP packet 6 including said response notification, an external IP address EA2 of said terminal T2 and said port number PN2 and then reaches at said terminal Tl, said connection server S2 commands a setting of an IP communication record R2 including a discrimination information of said logical terminal LP2 for said network node apparatus N2, said connection server SI commands a setting of an IP communication record Rl including a discrimination information of said logical terminal LP1 for said network node apparatus Nl, said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 7 that a source address is said external IP address EAl, a destination address is said external IP address EA2 of said terminal T2 and a destination port number is said port number PN2, said external IP packet 7 is judged at network node apparatus Nl whether an IP capsulation condition is 516 CA 02340293 2007-08-17 satisfied based on administration of said communication record Rl or not, when said IP capsulation condition is satisfied, said external IP packet 7 is capsulated, said capsulated packet becomes to an internal IP packet 7 that a destination address is said internal IP address IA2 for discriminating said logical terminal LP2 and is transferred in said communication path P12, and it is reversely capsulated at said network node apparatus N2 and then a restored external IP packet 7 is sent to said terminal T2, and when said terminal Tl transmits an external IP packet 9 that includes a communication cutting-off request and a destination address is said external IP address EA81, said external IP packet 9 becomes to an internal IP packet 9 includinq said communication cuttinq-off request and then reaches at said connection server SI, said connection servers SI and S2 send/receive a release messaqe (REL) or a release completion messaqe (RLC) and command a disappear of said communication records Rl and R2.
  2. 2
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein :said IP transfer network includes plural termination qateways GW, said termination qateways GW respectively include plural network node apparatus and a domain name server, plural terminals are connected to said IP transfer network, a terminal Tl is connected to a network node apparatus N1 in a termination qateway GW1 by a loqical terminal LP1 via a communication line LI, a terminal T2 is connected to a network node apparatus N2 in a termination qateway GW2 by a loqical terminal LP2 via a communication 517 CA 02340293 2007-08-17 line L2, and said domain name server holds a set of a telephone number or host name TNj (j=l, 2,3, ... ) and an external IP address EAj of a terminal Tj, an internal IP address IAj being a discrimination information of a logical terminal LPj and an internal IP address k of a termination gateway GWk carrying out a connection control of said terminal Tj, an IP communication record R81 including a discrimination information of said logical terminal LPl is set in said network node apparatus Nl, and an IP communication record R82 including a discrimination information of said logical terminal LP2 is set in said network node apparatus N2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2, wherein said external IP packet 1 includes a connection request and said telephone number or host name TN2 and a destination address thereof is a connection control request address EA81 which is an address for transmitting an external IP packet on a connection control of said termination gateways GW, said network node apparatus Nl inspects an IP capsulation condition define by said IP communication record R81 for an external IP address in said external IP packet 1, said external IP packet 1 which said IP capsulation condition is not satisfied is discarded, when said IP capsulation condition is satisfied, said network node apparatus Nl converts said external IP packet 1 into an internal IP packet 1 by a capsulation, said termination gateway GW1 obtains said telephone numbers or host names from said internal IP packet 1, and further obtains an external IP address EA2 of said terminal T2, an internal IP address IA2 being a discrimination 518 CA 02340293 2007-08-17 information of said logical terminal LP2 and an internal IP address IA92 of said termination gateway GW2 carrying out a connection control of said terminal T2 by using said domain name server DS1, and said termination gateway GW1 sends an initial address message (IAM) including the connection request to said termination gateway GW2, said termination gateway GW2 obtains said connection request, said telephone numbers or host names TNI and TN2, said external IP address EAl and EA2 and said internal IP address IAl and IA2 from said initial address message (IAM), said termination gateway GW2 sends an internal IP packet 2 including a receipt notification, said internal IP packet 2 is converted into an external IP packet 2 at said network node apparatus N2, said external IP packet 2 reaches at said terminal T2, and said termination gateway GW2 forms an address completion message (ACM) including a receipt propriety notification and sends it to said termination gateway GWl, said terminal T2 transmits an external IP packet 3 that includes a call-on notification for notifying a response preparation start and a destination address thereof is a connection control request address EA82, said external IP packet 3 is judged at said network node apparatus N2 whether an IP capsulation condition defined by said IP communication record R82 is satisfied or not, when said IP capsulation condition is satisfied, said external IP packet 3 becomes to an internal IP packet 3 including said call-on notification and then inputs to said termination gateway GW2, said termination gateway GW2 sends a call progress message (CPG) including said call-on notification to said termination gateway GWl, said termination gateway GW1 sends an internal IP packet 4 including said call-on 519 CA 02340293 2007-08-17 notification, said internal IP packet 4 becomes to an external IP packet 4 including said call-on notification at said network node apparatus Nl and reaches at said terminal Tl, said external IP packet 5 is judged whether said IP capsulation condition is satisfied or not, when said IP capsulation condition is satisfied, said external IP packet 5 becomes to an internal IP packet 5 including said call-on notification and then inputs to said termination gateway GW2, said termination gateway GW2 sends a response message (ANM) including said response notification to said termination gateway GW1, said termination gateway GW1 sends an internal IP packet 6 including said response notification and an external IP address EA2 of said terminal T2, said internal IP packet 6 becomes to an external IP packet 6 including said response notification and said external IP address EA2 of said terminal T2 at said network node apparatus Nl and then reaches at said terminal Tl, said termination gateway GW2 presents a setting of an IP communication record R2 including a discrimination information of said logical terminal LP2 for said network node apparatus N2, said termination gateway GW1 presents a setting of an IP communication record Rl including a discrimination information of said logical terminal LP1 for said network node apparatus Nl, said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet .7 that a destination address is said external IP address EA2 of said terminal T2, said external IP packet 7 inputs to said network node apparatus Nl, said external IP packet 520 CA 02340293 2007-08-17 7 is judged whether an IP capsulation condition is satisfied or not, when said IP capsulation condition is satisfied, said external IP packet 7 is converted into an internal IP packet 7 that a destination address is said internal IP address IA2 for discriminating said logical terminal LP2 and is transferred in said communication path P12, when said internal IP packet 7 reaches at said network node apparatus N2, it is restored to said external IP packet 7 and then reaches at said terminal T2, and when said terminal Tl transmits an external IP packet 9 that includes a communication cutting-off request and a destination address is said connection control request address EA81, said external IP packet 9 becomes to an internal IP packet 9 including said communication cuttingoff request at said network node apparatus Nl and then inputs to said termination gateway GW1, and said termination gateways GW1 and GW2 send/receive a release message (REL) or a release completion message (RLC) and command a disappear of said IP communication records Rl and R2.
  3. 3
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein:said IP transfer network includes plural network node apparatus, a connection server X, plural proxy connection servers and a domain name server X, plural terminals are connected to said IP transfer network, a terminal Tl having a telephone number TNI is connected to a network node apparatus Nl by a logical terminal LPl via a communication line LI, a terminal T2 having a telephone number TN2 is connected to a network 521 CA 02340293 2007-08-17 node apparatus N2 by a logical terminal LP2 via a communication line L2, and said domain name server X holds a set of a telephone number or host name TNj (j=l, 2,3, ... ) and an external IP address EAj of a terminal Tj and an internal IP address IAj being a discrimination information of a logical terminal LPj, an IP communication record R81 including a discrimination information of said logical terminal LPl is set in said network node apparatus Nl, and an IP communication record R82 including a discrimination information of said logical terminal LP2 is set in said network node apparatus N2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2, wherein said external IP packet 1 includes a connection request and said telephone numbers or host names TN2 and a destination address thereof is an external IP address EA81 of a proxy connection server PSI, said external IP packet 1 inputs to said network node apparatus Nl from said logical terminal LPl, said network node apparatus Nl inspects an IP capsulation condition defined by a rule of said IP communication record R81 for an external IP address in said external IP packet 1, said external IP packet 1 which said IP capsulation condition is not satisfied is discarded, when said IP capsulation condition is satisfied, said network node apparatus Nl forms a first type internal IP packet 11 by capsulating said external IP packet 1 and sends it, a destination address of said internal IP packet 11 is an internal IP address IA81 of said proxy connection server PSI, said proxy connection server PSI converts said 522 CA 02340293 2007-08-17 internal IP packet 11 into a second type internal IP packet 12 and sends it to a connection server X, said connection server X obtains said telephone numbers or host names TNI and TN2 from said internal IP packet 12, and further obtains an external IP address EA2 of said terminal T2 and an internal IP address IA2 being a discrimination information of said logical terminal LP2 by presenting said telephone number or host name TN2 to a domain name server DS1, said connection server X sends a second type internal IP packet 21 including a receipt notification, said internal IP packet 21 is converted into a first type internal IP packet 22 by a proxy connection server PS2, said internal IP packet 22 is converted into an external IP packet 2 including said receipt notification at said network node apparatus N2, and said external IP packet 2 reaches at said terminal T2, said terminal T2 transmits an external IP packet 3 that includes a call-on notification for notifying a response preparation start and a destination address thereof is an external IP address EA82 of a proxy connection server PS2, said external IP packet 3 is judged at said network node apparatus N2 whether it satisfies an IP capsulation condition defined by said IP communication record R82 or not, said external IP packet 3 becomes to a first type internal IP packet 31 including said call-on notification, and then becomes to a second type internal IP packet 32 and reaches at said connection server X, said connection server X sends a second type internal IP packet 41 including said call-on notification, said internal IP packet 41 becomes to a first type internal IP packet 42, and said internal IP packet 42 becomes to an external IP packet 4 including said call-on notification at 523 CA 02340293 2007-08-17 said network node apparatus Nl and then reaches at said terminal Tl, said terminal T2 transmits an external IP packet 5 including a response notification for notifying a response, an IP capsulation condition of said external IP packet 5 is judged at said network node apparatus N2 and becomes to a first type internal IP packet 51 including said response notification, said internal IP packet 51 becomes to a second type internal IP packet 52 and reaches at said connection server X, said connection server X sends a second type internal IP packet 61 including said response notification and said external IP address EA2 , said internal IP packet 61 becomes to a second type internal IP packet 62, said internal IP packet 62 becomes to an external IP packet 6 including said response notification and said external IP address EA2 and then reaches at said terminal Tl, said connection server X commands a setting of an IP communication records Rl and R2 including discrimination information of said logical terminals LP1 and LP2 for said network node apparatus Nl and N2, said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 7 that a destination address is said external IP address EA2 of said terminal, said external IP packet 7 is judged at network node apparatus Nl whether an IP capsulation condition is satisfied based on administration of said IP communication record Rl or not, when said IP capsulation condition is satisfied, said external IP packet 7 is capsulated, said capsulated packet becomes to an internal IP packet 7 that a destination 524 CA 02340293 2007-08-17 address is said internal IP address IA2 for discriminating said logical terminal LP2 and is transferred in said communication path P12, and it is reversely capsulated at said network node apparatus N2 and then a restored external IP packet 7 is sent to said terminal T2, and when said terminal Tl transmits an external IP packet 9 that includes a communication cutting-off request and a destination address is said external IP address EA81, said external IP packet 9 becomes to an internal IP packet 9 including said communication cutting-off request and then reaches at said connection server X, and a disappear of said communication records RI and R2 is commanded.
  4. 4
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein :said IP transfer network includes plural network node apparatus, plural connection servers and a domain name server, a terminal Tl outside of said IP transfer network is connected to a network node apparatus Nl by a logical terminal LPl via a communication line Ll, and a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2, wherein said external IP packet 1 includes a connection request and a telephone number or host name TN2 of said terminal T2 and a destination address thereof is an address of a connection server Si, said external IP packet 1 inputs to said network node apparatus Nl from logical terminal LPl, and an IP 525 CA 02340293 2007-08-17 capsulation condition is inspected according to a rule of said IP communication record R81, when said IP capsulation condition is satisfied, said external IP packet 1 becomes to an internal IP packet 1 and then reaches at said connection server Si, said connection server SI obtains an external IP address EA2 of said terminal T2, an internal IP address IA2 for discriminating said logical terminal LP2 and an internal IP address 2 of said connection server S2 carrying out a connection control of said terminal T2 by presenting said telephone number or host name TN2 to a domain name server DS1, and sends an initial address message (IAM) including said connection request to said connection server S2, when said connection server S2 sends an internal IP packet 2 including a connection request notification, said internal IP packet 2 is converted into an external IP packet 2 according to a rule of an IP communication record R82 in said network node apparatus N2 and then is sent to said terminal T2, an external IP packet 3 including said call-on notification is sent from said terminal T2, 'said external IP packet 3 is converted into an internal IP packet 3 at said network node apparatus N2 according to a rule of said IP communication record R82 and then reaches at said connection server S2, and said connection server S2 forms a call progress message (CPG) including said call-on notification and sends it to said connection server SI, when said terminal T2 transmits an internal IP packet 4 including said call-on notification, said internal IP packet 4 is converted into an external IP packet 4 and then reaches at said terminal Tl, 526 CA 02340293 2007-08-17 when an external IP packet 5 including a response notification from said terminal T2, said external IP packet 5 is converted into an internal IP packet 5 at said network node apparatus N2 and then reaches at said connection server S2, said connection server S2 forms a response message (ANM) including said response notification and sends it to said connection server SI, when said connection server Si sends an internal IP packet 6 including said response notification and said external IP address EA2, said internal IP packet 6 reaches at said terminal Tl, said connection servers SI and S2 respectively command setting of IP communication records RI and R2 including internal IP address IAl and IA2 for discriminating said logical terminals LPl and LP2 for said network node apparatus Nl and N2, and said IP communication records RI and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 7 that a destination address is said external IP address EA2 of said terminal T2, said external IP packet 7 is judged at network node apparatus Nl whether an IP capsulation condition is satisfied based on a rule of said IP communication record RI or not, said external IP packet 7 becomes to an internal· IP packet 7 that a destination address is said internal IP address IA2, and said internal IP packet 7 is transferred in said communication path P12, and an external IP packet 7 restored at network node apparatus N2 is sent to said terminal T2, and when said terminal Tl transmits an external IP packet 9 that includes a communication cutting-off request and a destination address is an address of said connection server 527 CA 02340293 2007-08-17 SI, said external IP packet 9 including said communication cutting-off request reaches at said connection server SI, said connection servers SI and S2 send/receive a release message (REL) or a release completion message (RLC) and command a disappear of said communication records RI and R2.
  5. 5
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein :said IP transfer network includes plural network node apparatus, plural connection servers and a domain name server, a terminal Tl outside of said IP transfer network is connected to a network node apparatus Nl by a logical terminal LPl via a communication line Ll, and a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 including a connection request and a telephone number or host name TN2 of said terminal T2, said external IP packet 1 inputs to said network node apparatus Nl from said logical terminal LPl, said network node apparatus Nl sends said connection request and said telephone number or host name TN2, said connection server SI obtains an external IP address EA2 of said terminal T2 and an IP address IA2 of said connection server S2 carrying out a connection control of said terminal T2 by presenting said telephone number or host name TN2 to a domain name server DS1, said connection server Si sends an initial address message (IAM) including said connection request to said connection server S2, and 528 CA 02340293 2007-08-17 said connection server S2 sends a connection request notification to said terminal T2 having said external IP address EA2, said terminal T2 transmits said response notification to said connection server S2, said connection server S2 sends said response notification to said connection server SI, and said connection server SI sends said response notification to said terminal Tl, said connection servers Si and S2 respectively command setting of IP communication records Rl and R2 including internal IP address IAl and IA2 for discriminating said logical terminals LP1 and LP2 for said network node apparatus Nl and N2, and said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 2 that a destination address is said external IP address EA2 of said terminal T2, said external IP packet 2 is judged at network node apparatus Nl whether an IP capsulation condition is satisfied based on a rule of said IP communication record Rl or not, said external IP packet 2 becomes to an internal IP packet 2 that a destination address is said internal IP address IA2, and said internal IP packet 2 is transferred in said communication path P12, and an external IP packet 2 restored at network node apparatus N2 is sent to said terminal T2, and when said terminal Tl transmits a communication cutting-off request to said connection server SI, said connection servers SI and S2 send/receive a release message (REL) or a release completion message (RLC) and command a disappear of said communication records Rl and R2. 529 CA 02340293 2007-08-17
  6. 6
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein:said IP transfer network includes plural network node apparatus, plural connection servers, plural proxy connection servers and a domain name server, plural terminals are connected to said IP transfer network, a terminal Tl is connected to a network node apparatus Nl by a logical terminal LPl via a communication line LI, a terminal T2 is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, and said domain name server holds a set of a telephone number or host name TNj (j=l, 2,3, ... ) and an external IP address EAj of a terminal Tj, a discrimination information IAj of a logical terminal LPj and an internal IP address k of an internal address k carrying out a connection control of said terminal Tj, an IP communication record R81 including a discrimination information of said logical terminal LPl is set in said network node apparatus Nl, and an IP communication record R82 including a discrimination information of said logical terminal LP2 is set in said network node apparatus N2, said terminal.Tl transmits an external IP packet 1 for connecting to said terminal T2, wherein said external IP packet 1 includes a connection request and said telephone numbers or host names TNI andTN2 and a destination address thereof is an external IP address EA81 of a proxy connection server PSI, said network node apparatus Nl inspects a simple capsulation condition defined by a rule of said IP communication record R81 for external IP address in said external IP packet 1, wherein said simple capsulation is 530 CA 02340293 2007-08-17 that a simple header without a source address is added to said external IP packet 1, said external IP packet 1 which said simple capsulation condition is not satisfied is discarded, when said simple capsulation condition is satisfied, said network node apparatus Nl forms a first type internal IP packet 11 by simply capsulating said external IP packet 1 and sends it, a destination address of said internal IP packet 11 is an internal IP address IA81 of said proxy connection server PSI, and said proxy connection server PSI converts said internal IP packet 11 into a second type internal IP packet 12 and sends it to a connection server SI, said connection server SI obtains said telephone numbers or host names TNI and TN2 and said external IP address EAl from said internal IP packet 12, and further obtains an external IP address EA2 of said terminal T2, a discrimination information IA2 of said logical terminal LP2 and an internal IP address IA92 of said connection server S2 carrying out a connection control of said terminal T2 by presenting said telephone number TN2 of said destination terminal T2 to a domain name server DS1, said connection server SI sends an initial address message (IAM) including said connection request to said connection server S2, said connection server S2 obtains said telephone numbers TNI and TN2, said external IP address EAl and EA2 and said internal IP address IAl and IA2 from said initial address message (IAM), said connection server S2 sends a second type internal IP packet 21 including a receipt notification, said internal IP packet 21 is converted into a first type internal IP packet 22 by a proxy connection server PS2, said internal IP packet 22 is converted into an external IP packet 2 531 CA 02340293 2007-08-17 including said receipt notification at said network node apparatus N2, said external IP packet 2 reaches at said terminal T2, and said connection server S2 forms an address completion message (ACM) including a receipt propriety notification and sends it to said connection server Si, said terminal T2 transmits an external IP packet 3 that includes a call-on notification for notifying a response preparation start and a destination address thereof is an external IP address EA82 of a proxy connection server PS2, an external IP address of said external IP packet 3 is judged at said network node apparatus N2 according to a simple capsulation condition defined by said IP communication record R82, said external IP address becomes to a first type internal IP packet 31 including said call-on notification, and then becomes to a second type internal IP packet 32 and then reaches at said connection server S2, said connection server S2 forms a call progress message (CPG) including said call-on notification and sends it to said connection server Si, said connection server SI sends a second type internal IP packet 41 including said call-on notification, said internal IP packet 41 becomes to a first type internal IP packet 42 and becomes to an external IP packet 4 including said call-on notification at said network node apparatus Nl, and said external IP packet 4 reaches at said terminal Tl, said terminal T2 transmits an external IP packet 5 including a response notification for notifying a response and a port number PN2 of said terminal T2, a simple capsulation condition of said external IP packet 5 is judged at said network node apparatus N2 and becomes to a first type internal IP packet 51 including said response notification, said internal IP packet 51 becomes to a 532 CA 02340293 2007-08-17 second type internal IP packet 52 and reaches at said connection server S2, said connection server S2 forms a response message (ANM) including said response notification and said port number PN2 and sends it to said connection server Si, said connection server SI sends a second type internal IP packet 61 including said response notification, an external IP address EA2 of said terminal T2 and said port number PN2, said internal IP packet 61 becomes a first type internal IP packet 62, said internal IP packet 62 becomes to an external IP packet 6 including said response notification at said network node apparatus Nl, and said external IP packet 6 reaches at said terminal Tl, said connection server S2 commands a setting of an IP communication record R2 including a discrimination information of said logical terminal LP2 for said network node apparatus N2, said connection server Si commands a setting of an IP communication record Rl including a discrimination information of said logical terminal LP1 for said network node apparatus Nl, and said IP communication records Rl and R2 define a.communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 7 that a source address is said external IP address EAl, a destination address is said external IP address EA2 of said terminal T2 and a destination port number is said port number PN2, said external IP packet 7 is judged at network node apparatus Nl whether a simple capsulation condition is satisfied based on administration of said communication record Rl or not, when said simple capsulation condition is satisfied, said external IP packet 7 is simply capsulated, said simply capsulated packet becomes to an internal IP packet 7 that a 533 CA 02340293 2007-08-17 destination address is an internal IP address IA2x defined based on said discrimination information IA2 of said logical terminal LP2 and is transferred in said communication path P12, and· it is reversely and simply capsulated at said network node apparatus N2 and then a restored external IP packet 7 is sent to said terminal T2, and when said terminal Tl transmits an external IP packet 9 that includes a communication cutting-off request and a destination address is said external IP address EA81, said external IP packet 9 becomes to an internal IP packet 9 including said communication cutting-off request and then reaches at said connection server SI, said connection servers SI and S2 send/receive a release message (REL) or a release completion message (RLC) and command a disappear of said communication records Rl and R2.
  7. 7
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein :said IP transfer network includes plural network node apparatus, plural connection servers and a domain name server, a terminal Tl outside of said IP transfer network is connected to a network node apparatus N1 by a logical terminal LP1 via a communication line LI, a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2 by using a telephone number or host name, wherein said external IP packet 1 includes a connection request and a telephone number or host name TN2 534 CA 02340293 2007-08-17 of said terminal T2, said external IP packet 1 inputs to said network node apparatus Nl from said logical terminal LP1, said network node apparatus Nl sends said connection request and said telephone number or host name TN2 to a connection server X, said connection server X obtains an external IP address EA2 of said terminal T2 by presenting said telephone number or host name TN2 to said domain name server DS, said connection server X sends a connection request notification to said terminal T2 having said external IP address EA2, said terminal T2 transmits a response notification to said connection server X, and said connection server X sends said response notification to said terminal Tl, said connection server X commands a setting of IP communication records Rl and R2 including internal IP address IA1 and IA2 for discriminating said logical terminals LP1 and LP2 for said network node apparatus Nl and N2, and said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 2 of which source address is said external IP address EA2, said external IP packet 2 is judged at network node apparatus Nl whether an IP capsulation condition is satisfied or not, when said IP capsulation condition is satisfied, said external IP packet 2 becomes to an internal IP packet 2 of which destination address is said internal IP address IA2 and is transferred in said communication path P12, and an external IP packet 2 which is restored at said network node apparatus N2 is sent to said terminal T2, and 535 CA 02340293 2007-08-17 when said terminal Tl transmits a communication cutting-off request to said connection server X, said connection server X commands a disappear of said IP communication records Rl and R2, whereby said communication path P12 is disappeared.
  8. 8
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein :said IP transfer network includes plural network node apparatus, plural connection servers and a domain name server, a terminal Tl outside of said IP transfer network is connected to a network node apparatus Nl by a logical terminal LPl via a communication line LI, a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2 by using a telephone number or host name, wherein said external IP packet 1 includes a connection request and a telephone number or host name TN2 of said terminal T2, said external IP packet 1 inputs to said network node apparatus Nl from said logical tèrminal LPl, said network node apparatus Nl sends said connection request and said telephone number or host name TN2 to a connection server X, said connection server X obtains an external IP address EA2 of said terminal T2 by presenting said telephone number or host name TN2 to said domain name server DS, said connection server X sends a connection request notification to said terminal T2 having said external IP address EA2, 536 CA 02340293 2007-08-17 said terminal T2 transmits a response notification to said connection server X, and said connection server X sends said response notification to said terminal Tl, said connection server X commands a setting of simple capsulation communication records Rl and R2 including internal IP address IA1 and IA2 for discriminating said logical terminals LP1 and LP2 for said network node apparatus Nl and N2, wherein said simple capsulation is that a simple header without a source address is added to an external IP packet, and said simple capsulation communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 2 of which source address is said external IP address EA2, said external IP packet 2 is judged at network node apparatus Nl whether a simple capsulation condition is satisfied or not,' when said simple capsulation condition is satisfied, said external IP packet 2 becomes to an internal IP packet 2 of which destination address is said internal IP address IA2 and is transferred in said communication path P12, and an external IP packet 2 which is restored at said network node apparatus N2 is sent to said terminal T2, and when said terminal Tl transmits a communication cutting-off request to said connection server X, said connection server X commands a disappear of said simple capsulation communication records Rl and R2, whereby said communication path P12 is disappeared.
  9. 9
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein:537 CA 02340293 2007-08-17 said IP transfer network includes plural network node apparatus, plural connection servers and plural domain name servers, a terminal Tl outside of said IP transfer network is connected to a network node apparatus Nl by a logical terminal LP1 via a communication line Li, a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2 by using a telephone number or host name, wherein said external IP packet 1 includes a connection request and a telephone number or host name TN2 of said terminal T2, said external IP packet 1 inputs to said network node apparatus Nl from said logical terminal LP1, said network node apparatus Nl sends said connection request and said telephone number or host name TN2 to a connection server SI, said connection server SI obtains an external IP address EA2 of said terminal T2 and an internal IP address 2 of a connection server S2 carrying out a connection control of said terminal T2 by presenting said telephone number or host name TN2 to said domain name server DS1, said connection server SI sends an initial address message (IAM) including said connection request to said connection server S2, and said connection server S2 said connection request notification to said terminal T2 having said external IP address EA2, said terminal T2 transmits a response notification to said connection server S2, said connection server S2 sends said response notification to said connection server Si, and said connection server SI sends said response notification to said terminal Tl, 538 CA 02340293 2007-08-17 said connection server SI and S2 command a setting of simple capsulation communication records Rl and R2 including identifiers IA1 and IA2 for discriminating said logical terminals LPl and LP2 for said network node apparatus Nl and N2, wherein said simple capsulation is that a simple header without a· source address is added to an external IP packet, and said simple capsulation communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 2 of which source address is said external IP address EA2, said external IP packet 2 is judged at network node apparatus Nl whether a simple capsulation condition is satisfied according to a rule of said simple capsulation communication record Rl or not, when said simple capsulation condition is satisfied, said external IP packet 2 becomes to an internal IP packet 2 including said external IP packet 2 and said identifier IA2 and is transferred in said communication path P12, and an external IP packet 2 which is restored at said network node apparatus N2 is sent to said terminal T2, and when said terminal Tl transmits a communication cutting-off request to said connection server Si , said connection servers Si and S2 command a disappear of said simple capsulation communication records Rl and R2, whereby said communication path P12 is disappeared.
  10. 10
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein:said IP transfer network includes plural network node apparatus, a terminal Tl outside of said IP transfer 539 CA 02340293 2007-08-17 network is connected to a network node apparatus Nl by a logical terminal LP1 via a communication line Ll, a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2 by using a telephone number or host name, wherein said external IP packet 1 includes a connection request and a telephone number or host name TN2 of said terminal T2, said external IP packet 1 inputs to said network node apparatus Nl from said logical terminal LPl, said IP transfer network specifies an external IP address EA2 of said terminal T2 from said telephone number or host name TN2 and sends a connection request notification to said terminal T2 having said external IP address EA2, said terminal T2 transmits a response notification to said IP transfer network, and said IP transfer network sends said response notification to said terminal Tl, said IP transfer network commands a setting of IP communication records Rl and R2 including internal IP address IAl and IA2 for discriminating said logical terminals LPl and LP2 for said network node apparatus Nl and N2, and said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 2 of which source address is said external IP address EA2, said external IP packet 2 is judged at network node apparatus Nl whether an IP capsulation condition is satisfied according to a rule of said IP communication record Rl or not, 540 CA 02340293 2007-08-17 when said IP capsulation condition is satisfied, said external IP packet 2 becomes to an internal IP packet 2 of which destination address is said internal IP address IA2 and is transferred in said communication path P12, and an external IP packet 2 which is restored at said network node apparatus N2 is sent to said terminal T2, and when said terminal Tl transmits a communication cutting-off request to said IP transfer network, said IP transfer network commands a disappear of said IP communication records Rl and R2, and said communication path P12 is disappeared.
  11. 11
    A terminal-to-terminal communication connection control method with employment of an IP transfer network, wherein :said IP transfer network includes plural network node apparatus, a terminal Tl outside of said IP transfer network is connected to a network node apparatus Nl by a logical terminal LPl via a communication line Ll, a terminal T2 outside of said IP transfer network is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said terminal Tl transmits an external IP packet 1 for connecting to said terminal T2 by using a telephone number or host name, wherein said external IP packet 1 includes a connection request and a telephone number or host name TN2 of said terminal T2, said external IP packet 1 inputs to said network node apparatus Nl from said logical terminal LPl, said IP transfer network specifies an external IP address EA2 of said terminal T2 from said telephone number or host name TN2 and sends a connection request notification to said terminal T2 having said external IP address EA2, 541 CA 02340293 2007-08-17 said terminal T2 transmits a response notification to said IP transfer network, and said IP transfer network sends said response notification to said terminal Tl, said IP transfer network commands a setting of simple capsulation communication records Rl and R2 including identifiers IAl and IA2 for discriminating said logical terminals LP1 and LP2 for said network node apparatus Nl and N2, wherein said simple capsulation is that a simple header without a source address is added to an external IP packet, and said simple capsulation communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 2 of which source address is said external IP address EA2, said external IP packet 2 is judged at network node apparatus Nl whether a simple capsulation condition is satisfied according to a rule of said simple capsulation communication record Rl or not, when said simple capsulation condition is satisfied, said external IP packet 2 becomes to an internal IP packet including said external IP packet 2 and said identifier IA2 and is transferred in said communication path P12, and an external IP packet 2 which is restored at said network node apparatus N2 is sent to said terminal T2, and when said terminal Tl transmits a communication cutting-off request to said IP transfer network, said IP transfer network commands a disappear of said simple capsulation communication records Rl and R2, and said communication path P12 is disappeared. 542 CA 02340293 2007-08-17
  12. 12
    A terminal-to-terminal communication connection control· method with employment of an IP transfer network, wherein:said IP transfer network includes plural network node apparatus, plural terminals are connected to said IP transfer network, a terminal Tl is connected to a network node apparatus Nl by a logical terminal LPl via a communication line LI, a terminal T2 is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, and said IP transfer network holds a set of a telephone number or host name TNj (j = 1, 2,3, . . . ) and external IP address EAj of a terminal Tj, an internal IP address IAj for discriminating a logical terminal LPj, an IP communication record R81 including a discrimination information of said logical terminal LPl is set in said network node apparatus Nl, and an IP communication record R82 including a discrimination information of said logical terminal LP2 is set in said network node apparatus N2, said terminal Tl transmits an external IP packet 1 in said IP transfer network for connecting to said terminal T2, wherein said external IP packet 1 includes a connection request and said telephone numbers or host names TN2 and a destination address thereof is a connection control request address EA81 which is an address for transferring an external IP packet in said IP transfer network, and said external IP packet inputs to said network node apparatus Nl from said logical terminal LPl, said network node apparatus Nl inspects an IP capsulation condition to be satisfied by an external IP address in said external IP packet 1 according to a rule of said IP communication record R81, 543 CA 02340293 2007-08-17 said external IP packet 1 which said IP capsulation condition is not satisfied is discarded, when said IP capsulation condition is satisfied, said network node apparatus Ni capsulâtes said external IP packet 1 and inputs it to said IP transfer network as an internal IP packet, said IP transfer network obtains said telephone numbers or host names TNI and TN2 from said internal IP packet 1 and further obtains an external IP address EA2 of said terminal T2 and internal IP address IA2 for discriminating said logical terminal LP2 by using said telephone number or host name TN2, said IP transfer network sends an internal IP packet 2 including a receipt notification, said internal IP packet 2 is converted into an external IP packet 2 including said receipt notification at said network node apparatus N2 and then reaches at said terminal T2, said terminal T2 transmits an external IP packet 3 that includes a call-on notification for notifying a response preparation start and a destination address thereof is said connection control request address EA82, an external IP address of said external IP packet 3 is judged at said network node apparatus N2 according to an IP capsulation condition defined by said IP communication record R82, when said IP capsulation condition is satisfied, and said external IP packet 3 becomes to an internal IP packet 3 including said call-on notification and then inputted to said IP transfer network, said IP transfer network forms an internal IP packet 4 including call-on notification and sends it, and said internal IP packet 4 becomes to an external IP packet 4 including said call-on notification at said network node apparatus Nl and then reaches at said terminal Tl, 544 CA 02340293 2007-08-17 said terminal T2 transmits an external IP packet 5 including a response notification for notifying a response, an IP capsulation condition of said external IP packet 5 is judged at said network node apparatus N2, becomes to an internal IP packet 5 including said response notification and inputs to said IP transfer network, said IP transfer network sends an internal IP packet 6 including said response notification and said external IP address EA2 of said terminal T2, and said internal IP packet 6 becomes an external IP packet 6 including said response notification an said external IP address EA2 of said terminal T2 at said terminal Tl and then reaches at said terminal Tl, said IP transfer network commands a setting of IP communication records Rl and R2 including discrimination information of said logical terminals LPl and LP2 for said network node apparatus Nl and N2, and said IP communication records Rl and R2 define a communication path P12 for transferring an internal IP packet between said network node apparatus Nl and N2, when said terminal Tl transmits an external IP packet 7 of which destination address is said external IP address EA2 of said terminal T2, said external IP packet 7 is judged at network node apparatus Nl whether an IP capsulation condition is satisfied based on administration of said communication record Rl or not, when said IP capsulation condition is satisfied, said external IP packet 7 is capsulated, said capsulated packet becomes to an internal IP packet 7 that a destination address is said internal IP address IA2 for discriminating said logical terminal LP2 and is transferred in said communication path P12, and it is reversely capsulated at said network node apparatus N2 and then a restored external IP packet 7 is sent to said terminal T2, and 545 CA 02340293 2007-08-17 when said terminal TI transmits an external IP packet 9 that includes a communication cutting-off request and a destination address is said connection control request EA81, an internal IP packet 9 including said communication cutting-off request is inputted to said IP transfer network, said IP transfer network commands a disappear of said communication records Rl and R2.
  13. 13
    An IP communication system with employment of an IP transfer network, wherein:said IP transfer network includes plural network node apparatus and connection servers, plural terminals are connected to said IP transfer network, a terminal Tj (j=l,2,3,· · · ) is connected to a logical· terminal LPj of said network node apparatus via a communication line Lj, said network node apparatus includes an address management table and records set in said address management table, and a communication between said network node apparatus is capable by using said records, a terminal Tl is connected to a network node apparatus Nl via a communication line Ll and a logical terminal LP1, a terminal T2 is connected to a network node apparatus N2 via a communication line L2 and a logical terminal LP2, a connection server SI is connected to said network node apparatus Nl, a connection server S2 is connected to said network node apparatus N2, and said connection servers SI and S2 are connected to said network node apparatus Nl and N2 with communication lines in said IP transfer network, a telephone number or a host name of said terminal T2 and a request for a communication connection to said terminal T2 are sent to said connection server S2 from said terminal Tl via said network node apparatus Nl and said connection server Si, said connection server S2 sends to 546 CA 02340293 2007-08-17 said terminal T2 a request for communication connection to said terminal T2, and said terminal T2 sends to said connection server S2 a call-on notification for notifying a response preparing start and then sends a response notification, said network node apparatus N1 sets a record Rl including an address for discriminating said logical terminal LP2 at an address management table Hl in said network node apparatus Nl, said network node apparatus N2 sets a record R2 including an address for discriminating said logical terminal LP1 at an address management table H2 in said network node apparatus N2, and said records Rl and R2 define a communication path between said logical terminals LPl and LP2, said terminal Tl transfers an IP packet GP1 to said network node apparatus Nl, a destination address of said IP packet GP1 is an IP address of said terminal T2, said network node apparatus Nl sends an internal packet NP1 including said IP packet GP1 via said communication path by using said record Rl, said network node apparatus N2 restores said IP packet GP1 from said internal packet NP1, and said restored IP packet GP1 is sent to said terminal T2 via said logical terminal LP2, and said network node apparatus Nl and N2 delete said records Rl and R2 based on a communication cut-off request from said terminal Tl or T2, and the said communication path is deleted.
  14. 14
    An IP communication system with employment of an IP transfer network, wherein:said IP transfer network includes plural network node apparatus, and plural terminals outside of said IP transfer 547 CA 02340293 2007-08-17 network are connected to network node apparatus via logical terminals, a terminal Tl is connected to a network node apparatus Nl via a communication line Ll and a logical terminal LPl, a terminal T2 is connected to a network node apparatus N2 via a communication line L2 and a logical· terminal LP2, said network node apparatus Nl and N2 are connected each other with communication lines in said IP transfer network, and said network node apparatus Nl and N2 include address management tables Hl and H2 including writable and erasable records Rl and R2, said terminal Tl sends a connection request and a telephone number or host name TN2 of said destination terminal T2 to said network node apparatus Nl for a connection request to said terminal T2 by using a telephone number or host name, and said network node apparatus N2 sends to said terminal T2 a receipt notification based on said connection request, said terminal T2 sends to said network node apparatus N2 a call-on notification for notifying a response preparing start and then sends a response notification for notifying a response, said network node apparatus Nl sets a record Rl including an information for discriminating said logical terminal LP2 at an address management table Hl, said network node apparatus N2 sets a- record R2 including an information for discriminating said logical terminal LPl at an address management table H2, and a communication path P12 between said logical terminals LPl and LP2 is set, said terminal Tl sends an external IP packet GPl of said terminal T2 to said network node apparatus Nl, said network node apparatus Nl forms an internal IP packet NPl including said external IP packet GPl by using said record 548 CA 02340293 2007-08-17 Rl and sends said internal IP packet NP1 via said communication path P12, and said network node apparatus N2 restores said external IP packet GP1 from said internal IP packet NP1 and sends it to said terminal T2 via said logical terminal LP2, and said network node apparatus Nl and N2 delete said records Rl and R2 based on a communication cut-off reguest from said terminal Tl or T2, and the said communication path P12 is deleted.
  15. 19
    An IP communication system with employment of an IP transfer network, wherein:550 CA 02340293 2007-08-17 said IP transfer network includes plural network node apparatus, and plural terminals are connected to said IP transfer network, a terminal Tl is connected to a network node apparatus Nl by a logical terminal LP1 via a communication line Li, a terminal T2 is connected to a network node apparatus N2 by a logical terminal LP2 via a communication line L2, said network node apparatus Nl and N2 are connected each other with communication lines in said IP transfer network, and said network node apparatus Nl and N2 include address management tables Hl and H2 including writable and erasable records, said terminal Tl sends a connection request and a telephone number or host name TN2 of said destination terminal T2 to said network node apparatus Nl for a connection request to said terminal T2 by using a telephone number or host name, and said network node apparatus N2 sends to said terminal T2 a receipt notification based on said connection request, said terminal T2 sends to said network node apparatus N2 a call-on notification for notifying a response preparing start and then sends a response notification for notifying a response, said network node apparatus N2 sets a record R2 including an information for discriminating said logical terminal LP1, said network node apparatus Nl sets a record Rl including an information for discriminating said logical terminal LP2, and said records Rl and R2 define a communication path P12 for transferring an internal IP packet between said logical terminals LP1 and LP2, when said terminal Tl sends an external IP packet GPl of a destination address being an external IP address EA2 of said terminal T2, said external IP packet GPl is simple551 CA 02340293 2007-08-17 capsulated at said network node apparatus Nl based on said record Rl, and said simple-capsulation means that a simple header which includes a destination internal address and does not include a source internal address is added to said external IP packet GP1, said simple-capsulated IP packet becomes to an internal IP packet NP1 of which destination address is said logical terminal LP2 and then is transferred in said communication path P12, and said internal IP packet NP1 includes said external IP packet GP1, said external IP packet GP1 simple-capsulated and restored at said network node apparatus N2 is transferred to said terminal T2 via said logical terminal LP2, and said simple-capsulation is to delete a simple-header without a source address from said internal IP packet NP1, and said network node apparatus Nl and N2 delete said records Rl and R2 based on a communication cut-off request from said terminal Tl or T2, and the said communication path P12 is deleted. 552
Independent claims15