KR20000034643A - Method of establishing virtual circuits of multicast atm between ends for transmitting multicast ip traffic in atm network - Google Patents

Abstract

PURPOSE: A method of establishing virtual circuits of a multi cast ATM between ends for transmitting multi cast IP traffics in ATM network is provided so that although a communication is achieved through the several Logical IP Subnet (LIS), it is not necessary to pass a router by providing a protocol capable of applying a multi cast IP traffic within the ATM network. CONSTITUTION: A method of establishing virtual circuits of a multi cast ATM between ends for transmitting multi cast IP traffics in ATM network includes several steps. A step is to transmitting periodically a message of Multicast Callback Request from an ingress internet protocol multi cast router(21) to an egress internet protocol multi cast router(24). A step is to require an opening of a multi cast virtual circuit after determining the open of the multi cast virtual circuit. A step is to start the transmission of internet protocol multi cast packet through the multi cast virtual circuit. A step is to receive the internet protocol multi cast packet from an ingress internet protocol multi cast router.

Description

Multicast Eyes on A.M.M Network End-to-end multicast ATM to transmit traffic How to set up a virtual line

The present invention is an end-to-end multicast ATM virtual circuit (VC) for transmitting multicast Internet Protocol (hereinafter referred to as IP) traffic in an asynchronous transfer mode (hereinafter referred to as ATM) network. The method relates to a multicast IP network in an A.M. network that can effectively establish an end-to-end multicast ATM virtual circuit using only a simple control protocol without using an address resolution server. The present invention relates to a method for establishing an end-to-end multicast A.M virtual circuit for transmitting traffic.

In order to effectively transmit Internet traffic through the ATM network, which is widely established as a high-speed communication network, an effective interworking scheme with an ATM network, which is a connection-oriented communication method, and the Internet, which is a connectionless communication method, must be proposed. . This linkage was mainly focused on the Internet Engineering Task Force (IETF) and the ATM Forum. The 'Classical IP over ATM' method studied by IETF is a method of translating IP addresses into ATM addresses using ATMARP (ATM Addess Resolution Protocol) server, which is an address resolution server, and then opens IP virtual lines to transmit IP traffic. In this method, the operation range is limited within one logical Internet protocol subnet (hereinafter referred to as LIS). Therefore, communication between LISs requires a route through a router.

The proposed method to solve this problem is NHRP (Next Hop Resolution Protocol). This protocol can also resolve the ATM address belonging to another LIS by using an address analysis server called NHS (Next Hop Server) to resolve the destination address of the IP packet to an ATM address. In this way, IP packets can be efficiently transmitted without going through a router. LAN emulation researched at ATM Forum is a method of interworking ATM and LAN MAC layer through address analysis server, and MPOA (Multi Protocol Over ATM) combines LAN emulation method and IETF's NHRP method to set up end-to-end ATM virtual line. To send IP traffic. However, since these methods use address resolution servers, they must provide complex procedures for information synchronization and management of address resolution servers. In addition, NHRP or MPOA does not provide a procedure for transmitting multicast IP traffic.

Another method of transmitting multicast IP traffic studied by the IETF to the ATM network is the Multicast Addess Resolution Server (MARS), which extends the ATMARP server to resolve the multicast IP address into multiple ATM addresses subscribed to the multicast receiver. It is a method for transmitting multicast IP traffic by establishing an end-to-end point-to-multipoint ATM virtual circuit. However, since the operation range is limited to one LIS, the method using MARS must pass through a router when communicating through multiple LISs, which causes a problem of degrading performance.

Accordingly, the present invention proposes a protocol for accommodating multicast IP traffic in an ATM network without an address interpretation server, and does not need to go through a router in the middle of communicating through multiple LISs. blood. End-to-end multicast ATM to transmit traffic The purpose is to provide a virtual line setting method.

Multicast I.P. in the A.M.M network according to the present invention for achieving the above object. End-to-end multicast ATM to transmit traffic The virtual line setting method may include periodically transmitting a multicast callback request message from an inlet Internet protocol multicast router to an exit Internet protocol multicast router, and the outlet Internet protocol multicast router that receives the multicast callback request message. After determining to establish a multicast virtual line, requesting to establish a multicast virtual line using information included in the multicast callback request message, and establishing a multicast asynchronous transmission mode virtual circuit from the egress internet protocol multicast router. Receiving, by the inlet Internet Protocol multicast router, a multicast asynchronous transmission mode virtual line and initiating Internet protocol multicast packet transmission through the set asynchronous transmission mode virtual line; And exiting from the multicast distribution tree by the exit internet protocol multicast router and receiving the internet protocol multicast packet from the inlet internet protocol multicast router.

1 (a) and 1 (b) are diagrams for explaining a method for establishing an end-to-end ATM virtual line for unicast IP traffic transmission.

2 (a) and 2 (b) are diagrams for explaining a method for establishing an end-to-end multicast ATM virtual line for transmitting multicast IP traffic.

<Description of the symbols for the main parts of the drawings>

20: transmitting end

21 to 28: first to ninth IP multicast router

29 to 31: first to third ATM switching

32 to 38: first to seventh multicast receiving end

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

In order to maximize the switching capability of ATM when interworking the Internet and ATM networks, a direct ATM virtual line (VC) must be established between the transmitting and receiving end of IP traffic.

1 (a) and 1 (b) are diagrams for explaining a method for establishing an end-to-end ATM virtual line for unicast IP traffic transmission. It is a RISP (Receiver-Initiated Shortcut Path) protocol that can establish an end-to-end ATM virtual line without an address resolution server when transmitting unicast IP traffic over multiple logical Internet protocol side networks (LIS1 to LIS3).

Initial IP packets transmitted by the transmitting end 11 are transmitted along an existing IP routing path. When the transmitting end 11 detects the flow of IP traffic destined for a specific destination (101), it transmits a " Callback Request " message including its IP address and ATM address through the first to fourth IP routers 12 to 15. And transmits to the receiving end 16 (102). When the "Callback Request" message is received, the receiving end 16 establishes an ATM virtual line using the ATM address of the transmitting end 11 carried in the message (103). Thereafter, the sender 11 transmits a " Callback Response " message (104). When the transmitting end 11 receives the "Callback Response" message, the transmitting end 11 sends the corresponding IP packets to the receiving end 16 through the newly opened ATM virtual line along the first and second ATM switches 17 and 18. send.

By such a procedure, IP traffic transmitted through a plurality of LISs (LIS1 to LIS3) can be implemented without using an address analysis server so that it can be transmitted through an end-to-end ATM virtual line without passing through a router.

The present invention can extend the end-to-end ATM virtual line establishment procedure for unicast IP traffic, thereby establishing an end-to-end point-to-multipoint multicast ATM virtual line for multicast IP traffic transmission that NHRP or MARS could not provide. Present a protocol. Recently, many Internet applications using multicast IP traffic such as video conferencing and distance education have emerged, and these multicast Internet applications require high quality of service unlike other applications. Accordingly, it is necessary to transmit IP traffic at high speed by using the multicast ATM virtual line as in the present invention. NHRP or MPOA described above can establish an end-to-end ATM virtual circuit, but this procedure is applicable only to unicast IP traffic. In addition, since MARS can establish a multicast ATM virtual line but is limited to one LIS, an end-to-end ATM virtual line cannot be established. Therefore, a protocol for establishing an end-to-end multicast ATM virtual line as in the present invention is required. .

2 (a) and 2 (b) are diagrams for explaining a method for establishing an end-to-end multicast ATM virtual line for multicast IP traffic transmission.

First, the ingress multicast router (first multicast router; 21) is periodically directed to the destination or exit multicast router (fourth, sixth, eighth multicast router; 24, 26, 28). callback request "message is transmitted (201). That is, the first IP multicast router 21 passes through the second and third IP multicast routers 22 and 23 to the fourth IP multicast router 24, and the second and fifth multicast routers 22, 25, the multicast callback request message is transmitted to the sixth IP multicast router 26 through the seventh IP multicast router 27 through the seventh IP multicast router 27. The reason for the periodic transmission of the "Multicast callback request" message is that members of the multicast group (32 to 38) dynamically change on the Internet, so that end-to-end ATM virtual circuits can be opened to new members who join or leave the network. To ensure that

The message " Multicast callback request " includes the ATM address of the inlet IP multicast router 21 and is sent to the outlet IP multicast routers 24, 26, 28 along the existing IP multicast routing path. The egress IP multicast router 24, 26, 28 determines the establishment of the multicast virtual line after receiving the " Multicast callback request " message (202). Subsequently, a request for establishment of a multicast virtual line is transmitted by transmitting a message called LIJ (Leaf Initiated Join) using the ATM address of the inlet IP multicast router 21 delivered in the "Multicast callback request" message (203). This LIJ message transfer is through the ATM switch. That is, the fourth IP multicast router 24 passes through the second and first ATM switches 30 and 29 to the first IP multicast router 21, and the sixth IP multicast router 26 refers to the third and the third IP routers. The first IP multicast router 21 through the first ATM switches 31 and 29, and the eighth IP multicast router 28 through the first and third ATM switches 31 and 29 The LIJ message is transmitted to the cast router 21 to request the establishment of a multicast virtual line. The LIJ message is a message defined in the UNI 4.0 signaling procedure of the ATM Forum, and is used by the receiver to first subscribe to the multicast tree.

When the inlet IP multicast router 21 receives the LIJ message from the outlet IP multicast routers 24, 26, and 28, it sets up a multicast ATM virtual line using a "SETUP" message or an "ADD PARTY" message (204). ). By this, after the virtual line with the at least one exit IP multicast router is generated, the inlet IP multicast router 21 starts to transmit the multicast IP multicast packet via the established virtual line.

At this time, the exit IP multicast routers 24, 26, 28 receive the same packets twice from the multicast distribution tree and the multicast ATM virtual circuit composed of the existing multicast routers. To prevent this, the exit IP multicast routers 24, 26, 28 send a "PRUNE" message used by the multicast IP routing protocol, thereby leaving the multicast distribution tree and only through the multicast ATM virtual circuit. The IP multicast packet is received by the multicast receiver 32 through 38 (205).

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited.

As described above, according to the present invention, since the multicast IP traffic can be transmitted through the ATM network, it is not necessary to use an address analysis server. As a result, an initial delay due to an address resolution process for transmitting IP traffic or a complicated protocol for synchronization and management of an address resolution server becomes unnecessary. In addition, since the end-to-end multicast ATM virtual line can be established and used, the transmission efficiency of multicast IP traffic can be improved and the overall quality of service can be improved.

Claims (2)

Periodically sending a multicast callback request message from the ingress internet protocol multicast router to the egress internet protocol multicast router; Requesting the establishment of a multicast virtual line by using the information contained in the multicast callback request message after the egress internet protocol multicast router receiving the multicast callback request message determines to open a multicast virtual line; , Upon receipt of the multicast asynchronous transmission mode virtual circuit establishment request from the egress internet protocol multicast router, the inlet Internet protocol multicast router establishes a multicast asynchronous transmission mode virtual line, and sets the Internet protocol multiplication through the set asynchronous transmission mode virtual line. Initiating a cast packet transmission, And the exiting internet protocol multicast router leaves the multicast distribution tree and receives an internet protocol multicast packet from an inlet internet protocol multicast router. I'm blood. End-to-end multicast ATM to transmit traffic How to set up a virtual line. The method of claim 1, The multicast callback request message includes an asynchronous transmission mode address of an inlet internet protocol multicast router. End-to-end multicast ATM to transmit traffic How to set up a virtual line.