CN1968191A - Method for ATM message transmission based on IP network - Google Patents

Abstract

The invention relates to a method for transmitting ATM messages based on an IP network. The first ATM gateway and the second ATM gateway communicate interactively with each other. The first ATM gateway has an outgoing mapping table, and the second ATM gateway has an incoming mapping table. Execution: the first ATM gateway queries the mapping table according to the ATM parameter of the ATM message, and obtains the corresponding IP parameter; the first ATM gateway uses the IP parameter to carry out IP encapsulation of the ATM message, and sends it to the second ATM gateway; The ATM gateway queries the mapping table according to the IP parameters to obtain the ATM parameters, analyzes the IP packets according to the ATM parameters, and forwards the ATM packets obtained after parsing to the receiving device. The present invention sets a one-way or two-way mapping table on the first ATM gateway and the second ATM gateway, and performs corresponding encapsulation and decapsulation according to the mapping table, so that the ATM message can be transmitted to the required long-distance through the IP network. The device address in the ATM network, and does not require large-scale equipment transformation.

Description

The Method of Transmitting ATM Message Based on IP Network

technical field

The invention relates to a method for communicating ATM messages, in particular to a method for transmitting ATM messages based on an IP network.

Background technique

Asynchronous Transfer Mode (ATM) was designated by ITU-T in June 1992 as the transmission and mapping mode of broadband ISDN. ATM is a transmission mode developed on the basis of packet switching. In this mode Among them, the information uses the cell as the basic unit for information transmission, multiplexing and mapping. ATM cells are fixed-length packets that fill the channel with idle cells, thus dividing the channel into equal-length time segments. Each cell has a total of 53 bytes and is divided into 2 parts. The first 5 bytes are cell headers, which are mainly used for routing information and priority information; the latter 48 bytes are payloads, which are used to load information from different users and different services. Two common ATM cell formats are UNI cell format and NNI cell format. ATM is a connection-oriented mapping. Each Virtual Circuit (VC) is identified by a Virtual Path Identifier (VPI) and a Virtual Channel Identifier (VCI). A VPI/VCI value It has local significance only on a link between ATM nodes.

ATM Adaptation Layer (ATM Adaption Layer, AAL) is the interface between the high-level protocol and the ATM layer, which is responsible for switching the information between the ATM layer and the high-level protocol. At present, four types of AALs have been proposed: AAL1, AAL2, AAL3/4 and AAL5, and each type supports certain characteristic services in the ATM network. For different businesses, the processing methods are not the same. However, the information transmitted from the upper layer must be divided into 48-byte long loads, and then passed to the ATM layer. At the same time, the loads transmitted from the ATM layer are assembled, recovered, and then passed to the upper layer. Among them, AAL2 is aimed at low-speed variable-rate services with timing requirements, such as compressed voice. All digital information such as voice, data, and images must be cut, encapsulated into cells of a unified format, transmitted in the network, and restored to the required format at the receiving end. The AAL message needs to be divided into cells for transmission during ATM transmission, and after receiving the divided cells, the receiver reassembles them into an AAL message, in which VPI and VCI are located at the header of the cell.

Because ATM technology simplifies the exchange process, removes unnecessary data verification, adopts an easy-to-handle fixed cell format, thereby reducing the transmission delay, and the exchange rate is much higher than the traditional data network, suitable for high-speed data exchange services .

Although the ATM method has so many advantages, when an ATM message is transmitted from one site to another site far away, an ATM link must be established between the two sites. However, most of the existing The network is an IP network. Due to the development of the Internet, the IP protocol has been used to the greatest extent, and its popularity has reached an unprecedented level. It has increasingly become the de facto industry standard. Therefore, in order to realize the transmission of ATM messages, it is necessary to transform the IP network on a large scale , which is relatively expensive.

Contents of the invention

The purpose of the present invention is aimed at the difficulty that the long-distance transmission of existing ATM mode realizes, and the present invention proposes a kind of method based on IP network transmission ATM message, can realize the communication between ATM network on the basis of not transforming IP network Connect and communicate.

To achieve the above object, the present invention provides a method for transmitting ATM messages based on an IP network, wherein the first ATM gateway in the first ATM network and the second ATM gateway in the second ATM network communicate with each other, and the first ATM gateway in the second ATM network communicates interactively. An ATM gateway has an outgoing mapping table, and the second ATM gateway has an incoming mapping table, and the following steps are performed:

Step 1, when the first ATM network sends an ATM message to the second ATM network through the first ATM gateway, the first ATM gateway queries the outgoing mapping table according to the ATM parameter of the ATM message, Obtain the corresponding IP parameters;

Step 2, described first ATM gateway uses described IP parameter to carry out IP encapsulation to described ATM message, and sends to described second ATM gateway through IP network;

Step 3, described second ATM gateway receives the IP message through encapsulation, obtains ATM parameter according to the described inbound mapping table of described IP parameter query second ATM gateway, analyzes described IP message according to ATM parameter, will resolve The obtained ATM message is then forwarded to the corresponding device.

In the above-mentioned technical solution, the establishment of the outgoing mapping table and the incoming mapping table carried out before step 1 can be respectively established through call signaling, or the user can manually generate, and can also be in the first ATM gateway and the second ATM gateway Set up the two-way mapping table of ATM parameter and IP parameter (one-way mapping table refers to outgoing mapping table or incoming mapping table) respectively, to complete the two-way incoming and outgoing mapping of mutual ATM parameter and IP parameter of both sides. The establishment of the outgoing mapping table and the incoming mapping table includes: the ATM parameters are virtual path identifier and virtual channel identifier, and the IP parameters are source IP address, source port number, destination IP address and destination port number.

In step 2, the first ATM gateway encapsulates the IP header and the UDP header of the ATM message according to the IP parameters, and then sends it to the second ATM gateway through the IP network. Correspondingly in step 3, described second ATM gateway matches described inbound mapping table according to the IP parameter in the message after encapsulation, if matching is successful, then deletes the IP header and UDP of the message after described encapsulation header, and then forward the decapsulated ATM message to the corresponding device, if the match fails, continue to execute the IP transmission process.

When establishing the in-out mapping table of ATM parameters and IP parameters, the ATM parameters are in the form of two-tuples, i.e. virtual path identifier and virtual channel identifier, and the IP parameters are in the form of four-tuples, i.e. source IP address, source port number, Destination IP address and destination port number. When the encapsulated message is sent through the IP network, it can be transmitted in the form of UDP or TCP message.

In the present invention, a one-way or two-way mapping table and an in-mapping table are set on the first ATM gateway and the second ATM gateway, and corresponding encapsulation and decapsulation are performed according to the mapping table, so that the ATM message can be transmitted through the IP network to all The address of the device in the long-distance ATM network required.

The present invention adopts the mapping table of ATM two-tuple and IP four-tuple to carry out the mapping of ATM parameter and IP parameter, is very simple, and does not need large-scale equipment transformation, only needs to be aimed at the first ATM gateway and the second ATM gateway. .

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

FIG. 1 is a schematic diagram of the network structure of the method for transmitting ATM messages based on an IP network in the present invention.

FIG. 2 is a schematic flowchart of Embodiment 1 of the method for transmitting ATM packets based on an IP network according to the present invention.

FIG. 3 is a schematic flowchart of Embodiment 2 of the method for transmitting ATM packets based on an IP network in the present invention.

Detailed ways

The core idea of the present invention is: utilize the ATM gateway in the ATM network to convert the ATM message into the IP message carried by the IP protocol for long-distance transmission, and then pass the IP message through the ATM gateway in another ATM network. The ATM path information in the article is disassembled, and the ATM message is restored, and then the ATM message is sent to the corresponding equipment, thus realizing the communication between ATM networks. The ATM gateway is provided with an outgoing mapping table and an incoming mapping table for mapping IP parameters and ATM parameters, and supports ATM connection and IP connection at the same time.

As shown in Figure 1, it is the network structural representation of the method for transmitting ATM message based on IP network of the present invention, and in network, ATM equipment is all connected with ATM gateway 1,2 with virtual circuit (Virtual Circuit, be called for short VC), each A virtual circuit is usually identified by a virtual path identifier (Virtual Path Identifier, referred to as VPI) and a virtual channel identifier (Virtual Channel Identifier, referred to as VCI), and is connected to the first ATM network and the second ATM network through ATM gateways 1 and 2. An IP network refers to a network connected by communication through the IP protocol, such as the Internet.

Embodiment one

As shown in Figure 2, be the schematic flow sheet of embodiment one of the method for transmitting ATM message based on IP network of the present invention, complete the operation of transmitting by following steps:

Step 101, when the first ATM network sends an ATM message to the second ATM network through the ATM gateway 1, the ATM gateway 1 will query the outgoing mapping table stored in the first ATM gateway according to the ATM parameter, and according to the outgoing mapping table item Exactly match the content in to obtain the corresponding IP parameters;

Step 102, carry out IP encapsulation to ATM message then, encapsulate IP header and UDP header according to the IP parameter that obtains, then call IP message sending interface and send the ATM message after IP encapsulation to ATM gateway 2;

Step 103, when the ATM gateway 2 receives the encapsulated IP message sent by the first ATM network, query the incoming mapping table stored in the ATM gateway 2 according to the IP parameters, and perform an exact match according to the content incorporated in the mapping table , when the matching is successful, obtain the corresponding ATM parameters, then analyze the IP message according to the ATM parameters, remove the IP header and the UDP header of the message, convert it into internal ATM encapsulation, and send it to the corresponding ATM device.

In the foregoing embodiment, at first the ATM gateway of the first ATM network and the second ATM network sets up the access mapping table of ATM parameter and IP parameter, when setting, the access mapping table can be two-way setting, promptly can be by the first ATM network Send the message to the second ATM network, and also send the message to the first ATM network by the second ATM network in the opposite direction;

In the above-mentioned technical scheme, the ATM gateway must support both the ATM connection and the IP connection, while other ATM devices in the ATM network only need to support the ATM connection, so there is no need for large-scale transformation. Compatible with the IP network, in the selection of ATM parameters and IP parameters, the form of ATM two-tuple and IP four-tuple can be adopted, where the ATM two-tuple is VPI+VCI, and the IP four-tuple is the source IP address SrcIP+source port Sport number + destination IP address DstIP + destination port number Dport. The establishment of the in-out mapping table entry can be processed through call signaling or manually established, and a single-item or two-way out-in and in-out mapping table can be established during establishment.

For example, assume that the IP port number of ATM gateway 1 is 2000, the IP port number of ATM gateway 2 is 3000, and the outgoing mapping table and incoming mapping table have been processed through call signaling or manually established, as shown in Table 1-4, where Only some entries are listed. The outgoing mapping table may have a many-to-one situation, that is, multiple ATM binary groups correspond to a group of IP quadruples, but the incoming mapping table must correspond one-to-one.

Table 1: Outbound mapping table of ATM gateway 1 VPI VCI IP quadruple (SrcIP, SPort, DstIP, Dport) 100 2 (10.78.233.1, 2000, 10.78.233.2, 3000)

Table 2: Incoming mapping table of ATM gateway 1 IP quadruple (SrcIP, SPort, DstIP, Dport) VPI VCI (10.78.233.1, 2000, 10.78.233.2, 3000) 200 4

Table 3: Outbound mapping table of ATM gateway 2 VPI VCI IP quadruple (SrcIP, SPort, DstIP, Dport) 300 2 (10.78.233.1, 2000, 10.78.233.2, 3000)

Table 4: Incoming mapping table of ATM gateway 2 IP quadruple (SrcIP, SPort, DstIP, Dport) VPI VCI (10.78.233.1, 2000, 10.78.233.2, 3000) 200 4

When ATM device A in the first ATM network sends an ATM message to the second ATM network, it first transparently transmits the ATM message to ATM gateway 1 through the preset VC channel, and ATM gateway 1 Query in the mapping table, the ATM binary group of ATM equipment A is (100, 2) in this embodiment, corresponding to going out the mapping table, can look up IP quadruple group (10.78.233.1, 2000, 10.78.233.2, 3000 ), then construct the IP header and UDP header according to the IP quadruple, and attach them before the ATM message, and then call the IP layer sending function to send the message. If the IP parameter cannot be found when querying the mapping table, then Discard the ATM message, end operation; After the ATM gateway 2 in the second ATM network receives the IP message, carry out fragmentation reorganization, then look into mapping table according to the parameter of its IP four-tuple, obtain its ATM two-tuple (200, 4), and then forward the decapsulated ATM message to the corresponding ATM device according to the downlink (VPI, CID). If the table lookup fails, the IP transmission process is continued.

In addition, it should be noted that when the UDP port is allocated for business use, the SOCKET upper-layer application cannot use this port, and the target address is uniquely identified by the IP address and UDP port number group. When the gateway device also has other IP packets when interacting , if the port has been used by the ATM mapping table, the socket application of the gateway device should not use this port, otherwise the Socket may not receive the message.

Embodiment two

The present invention can handle two kinds of ATM message, and a kind of is the ATM cell of fixed length, and a kind of is AAL message, and these two kinds of ATM messages are applicable to last embodiment, in ATM network, if transmit When sending an AAL message, the AAL message must be disassembled into several fixed-length ATM cells before sending, but when it is transmitted through the IP protocol, it does not need to be disassembled into several fixed-length ATM cells. The specific process has been described in the previous embodiment.

The present embodiment description has increased the technical scheme of AAL message dismantling and recombination operation, as shown in Figure 3, is the schematic flow chart of embodiment two of the method for transmitting ATM message based on IP network of the present invention, comprises the following steps:

Step 201, when the first ATM network sends an AAL message to the second ATM network through the ATM gateway 1, the ATM gateway 1 will query the mapping table according to the ATM parameters, and perform an exact match according to the content in the mapping table entry, Obtain the corresponding IP parameters;

Step 202, the ATM adaptation layer of ATM gateway 1 disassembles the AAL message into several ATM cells, and this AAL message can be AAL1, AAL2, AAL3/4, AAL5;

Step 203, then carry out IP encapsulation to several ATM cells after dismantling, encapsulate IP header and UDP header according to the obtained IP parameter, then call the IP message sending interface to send the ATM cell after IP encapsulation to ATM gateway 2 ;

Step 204, when ATM gateway 2 receives the message that the first ATM network sends over, according to IP parameter inquiry into mapping table, carry out accurate matching according to the content in entering mapping table, when matching is successful, obtain corresponding ATM parameter;

Step 205, the IP header and the UDP header of message are removed, turn into internal ATM encapsulation, then several ATM cells are reorganized into AAL message by ATM adaptation layer, and described ATM adaptation layer reports according to ATM parameter The text is forwarded to the receiving device.

In the foregoing embodiment, at first the ATM gateway of the first ATM network and the second ATM network sets up the outgoing mapping table and the incoming mapping table of the ATM parameter and/or IP parameter, when setting, the outgoing mapping table and the incoming mapping table can be Two-way setting, that is, the message can be sent from the first ATM network to the second ATM network, and the message can also be sent from the second ATM network to the first ATM network in the opposite direction.

The solution of the present invention can adopt the TCP mode to carry the ATM message. When the TCP mode is adopted, it is necessary to establish a TCP connection between the ATM gateways of the two ATM networks before starting to transmit the ATM message. This mode is suitable for both ends of the communication Situation with few changes, as to which kind of bearer (TCP or UDP mode) to choose to use needs to be set, this setting is mainly reflected in the establishment of table entry, and the scheme of the present invention is applicable to ATM cell and AAL simultaneously message.

From above two embodiments, the present invention adopts the mapping table of ATM two-tuple and IP four-tuple to carry out the mapping of ATM parameter and IP parameter, is very simple, and does not need to carry out large-scale equipment transformation to existing equipment , it only needs to be set for the software in ATM gateway 1 and ATM gateway 2; and the present invention can be easily transmitted through the IP network no matter for single or multiple ATM cells or complete AAL messages, and the scope of application is relatively wide.

Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present invention, rather than limiting the understanding of the present invention. Although the present invention has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that: they can still modify or replace the technical solutions of the present invention without departing from the present invention. The spirit and scope of the technical proposal.

Claims (11)

1, a kind of method based on IP network transmission ATM message, by being in the first ATM gateway of the first ATM network and being in the second ATM gateway of the second ATM network interactive communication, it is characterized in that, described first ATM gateway There is an outgoing mapping table, and the second ATM gateway has an incoming mapping table, and the following steps are performed: Step 1, when the first ATM network sends an ATM message to the second ATM network through the first ATM gateway, the first ATM gateway queries the mapping table according to the ATM parameters of the ATM message, and obtains the corresponding IP parameters; Step 2, described first ATM gateway uses described IP parameter to carry out IP encapsulation to described ATM message, and sends to described second ATM gateway through IP network; Step 3, described second ATM gateway receives the IP message through encapsulation, obtains ATM parameter according to the described inbound mapping table of described IP parameter query second ATM gateway, analyzes described IP message according to ATM parameter, will resolve The obtained ATM message is then forwarded to the corresponding device. 2. The method for transmitting ATM messages based on an IP network according to claim 1, further comprising the following steps before said step 1: on said first ATM gateway and the second ATM gateway, through a call signal Establish the out-mapping table and/or in-mapping table of ATM parameters and IP parameters respectively in command mode. 3, the method for transmitting ATM message based on IP network according to claim 2, it is characterized in that, setting up operation is specifically: setting up ATM parameter as virtual path identifier and virtual channel identifier and IP parameter as source IP address, source The outbound mapping table and the inbound mapping table of port number, destination IP address and destination port number. 4. The method for transmitting ATM messages based on an IP network according to claim 1, characterized in that before said step 1, it also includes the step of: calling signaling on said first ATM gateway and second ATM gateway The two-way mapping table for the entry and exit of ATM parameters and IP parameters is established respectively. 5. The method for transmitting an ATM message based on an IP network according to claim 1, wherein said step 1 further comprises a step, when the first ATM gateway inquires about said outgoing message according to the ATM parameter of said ATM message If the IP parameter cannot be found in the mapping table, the ATM packet is discarded and the operation ends. 6. The method for transmitting an ATM message based on an IP network according to claim 1, wherein said step 2 is specifically: said first ATM gateway carries out IP header summing to said ATM message according to said IP parameter The UDP header is encapsulated and sent to the second ATM gateway through the IP network. 7. The method for transmitting ATM messages based on an IP network according to claim 6, characterized in that said step 3 is specifically: said second ATM gateway maps said inbound message according to the IP parameters in the encapsulated message If the matching is successful, the IP header and the UDP header of the encapsulated message are deleted, and then the decapsulated ATM message is forwarded to the corresponding device, and if the matching fails, the IP transmission process is continued. 8. The method for transmitting ATM messages based on an IP network according to claim 6, wherein the operation of sending to the second ATM gateway through the IP network is specifically: sending to the second ATM gateway through the IP network with UDP A second ATM gateway. 9. The method for transmitting an ATM message based on an IP network according to any one of claims 1 to 8, wherein the ATM message in the step 1 comprises: an ATM adaptation layer message or an ATM cell . 10. The method for transmitting an ATM message based on an IP network according to claim 9, wherein when the message sent is an ATM adaptation layer message, the ATM adaptation layer of the first ATM gateway transfers the ATM Adaptation layer packets are disassembled into multiple ATM cells. 11. The method for transmitting ATM messages based on an IP network according to claim 10, characterized in that, after querying the inbound mapping table in the step 3 to obtain the ATM parameters, the ATM adaptation of the second ATM gateway The layer reassembles the multiple ATM cells into the ATM adaptation layer message, and forwards the ATM adaptation layer message to the receiving device according to the ATM parameters.

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