CN100486202C

CN100486202C - System and method for realizing adaptive layer function in ATM exchange

Info

Publication number: CN100486202C
Application number: CNB011453818A
Authority: CN
Inventors: 肖理
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2001-12-29
Filing date: 2001-12-29
Publication date: 2009-05-06
Anticipated expiration: 2021-12-29
Also published as: CN1430385A

Abstract

A system to achieve function of adaptive layer in ATM exchanger includes at least one initialization module, one connection management module, one sending processing module, one segmentation processing module, one recombining operation module and one reception processing module. And a method for it includes the following steps: initialized processing; setting up and dismantling virtual connection; providing data packet for upper layer; forming public part of convergent sublayer protocol data packet CPCS-PDU by utilizing data packet provided from upper layer and other parameters; carrying on segmentation processing for CPCS-PDU and recombining to become CPCS-PDU according to AUU index of collected cell head as well as to be processed by the reception operation module; inspecting whether CPCS-PDU is correct or not.

Description

A kind of system and method for in ATM switch, realizing adaption layer function

Technical field

The present invention relates to ATM switch, realize the system and method for adaption layer function in particularly a kind of ATM switch.

Background technology

ATM switch is a kind of communication technology that combines the flexibility of Circuit-switched real-time and packet switching, it adopts a kind of grouping of regular length, it is cell, come transmission information, major function is that the cell from input port is quick, be routed to output port effectively, adaptation layer AAL (ATM Adaptation Layer ATM) as ATM switch, various information can be adapted to the data cell that 48 bytes are unit, flow and error control are provided, guarantee information is transmission reliably on atm network, and the function of AAL is indispensable in ATM switch: for example the signaling process of ATM switch must use AAL to realize; Also must use AAL when perhaps the administration order of each vendor A TM switch internal proprietary realizes in band, the AAL layer can be divided into types such as AAL0, AAL1, AAL2, AAL3/4, AAL5 again according to practical business.The present invention relates to the adaption function of AAL5,

The adaption function of AAL5 is normally realized by special chip at present, though it is strong to realize having disposal ability with special chip, advantages such as the supporting business type is many, but also exist the hardware designs complexity, cost is than problems such as height, differ greatly between the various dedicated processes chips simultaneously, the implementation of AAL5 and data structure are all different separately, therefore need different separately drivers to support, and also can't accomplish compatible between the driver, its final result is the portable relatively poor of each driver

And a kind of system and method for in ATM switch, realizing adaption layer function provided by the present invention, available software realizes the adaption function of AAL5, not only can save complicated dedicated processes chip, reduce cost, and this system and method may operate on different operating system and the different processor, adopt identical functions module and data structure, therefore have good portability.

Summary of the invention

The object of the present invention is to provide a kind of system and method for in ATM switch, realizing adaption layer function, to address the above problem, can adopt software approach to realize the adaption function of the adaptation layer AAL5 of ATM switch, do not need to depend on special-purpose process chip, can reduce the design complexity of hardware effectively, reduce hardware cost, portable good, and its handling property improves along with the raising of processor performance.

Above-mentioned purpose of the present invention is achieved in that a kind of system that realizes adaption layer function in ATM switch, realizes the SAR sublayer of AAL5 and the function of CPCS sublayer, it is characterized in that this system comprises at least:

One initialization module provides initialization interface, is used for the initialization of deal with data;

One connection management module provides the connection management interface, is used to handle the foundation and the dismounting of virtual connections;

One sends processing module, and transmission interface is provided, and is used to high-level interface that the packet transmission interface is provided;

One segment processing module is used for CPCS-PDU is carried out staged operation;

One reorganization operational module extracts a mouthful extraction cell from cell and recombinates; And

One receiving processing module provides receiving interface, is used to receive data, and packet is handed in layer handle;

The virtual connections table of initialization process is carried out in the utilization of described connection processing module through described initialization module, set up and remove virtual connections, described transmission processing module is sent to cell through transmit queue with cell and inserts mouth, described segment processing module is inserted a mouthful remittance physical layer cell from described cell, again cell is delivered to cell and extracted mouth, described reorganization processing module is extracted a mouthful extraction cell from described cell, indication is recombinated according to header, and described receiving processing module receives described reorganization processing module result.

We propose a kind of method that realizes adaption layer function in ATM switch, realize the function of adaptation layer AAL5 in the ATM switch in order to utilize software, and this method comprises the following step at least:

At first variable, data structure are carried out initialization process;

Foundation and dismounting to virtual connections manage;

For the upper strata provides packet;

Judge whether to exist the connection that can send;

Packet and the parameter of utilizing the upper strata to provide form Common Part Convergence Sublayer protocol data bag CPCS-PDU;

CPCS-PDU carries out segment processing to Convergence Sublayer protocol data bag, inserts mouth from cell, imports the physical layer cell flow;

Extract a mouthful extraction cell from cell, check header, whether recombinate with decision;

AUU indication according to header reassembles into CPCS-PDU, and flow processing is received in handing-over;

Whether CPCS-PDU is correct in check; And

Extract the information of the CPCS-PDU afterbody domain of dependence, hand in layer together with packet and handle.

Relevant detailed content of the present invention and technology now just cooperate graphic being described as follows:

Description of drawings

Fig. 1 is an ATM switch line interface unit block diagram of the present invention;

Fig. 2 is a system configuration schematic diagram of the present invention;

Fig. 3 is an initialization module flow chart of the present invention;

Fig. 4 is a connection management module flow chart of the present invention;

Fig. 5 is a transmission processing module flow chart of the present invention;

Fig. 6 is a segment processing module flow chart of the present invention;

Fig. 7 is a reorganization processing module flow chart of the present invention.

Fig. 8 is a receiving processing module flow chart of the present invention.

Embodiment

Below in conjunction with embodiment and accompanying drawing thereof, the present invention is described in further detail.

The system and method for in ATM switch, realizing adaption layer function disclosed according to the present invention, see also accompanying drawing, as shown in Figure 1, can see basic structure as the line interface unit of the important component part of ATM switch, it comprises physical layer interface (101), ATM UNI process chip (102), switching network interface (103) and master cpu (105), in the prior art, use special chip (104) to realize the segmentation and the reorganization of upper layer data bag, this chip is positioned between ATM UNI process chip (102) and the master cpu (105), the cell that can extract appointment from cell flow reassembles into packet and gives the master cpu processing, otherwise the packet segmentation that also master cpu can be given it becomes cell and incorporates in the cell flow, system and method provided by the present invention is used the software AAL that is loaded on the master cpu (105) and is replaced special chip (104), because ATM UNI process chip all possesses the ability of being extracted and inserted ATM cell by master cpu usually, this is just for realizing that with software the AAL5 Segmentation and Reassembly provides hardware foundation.

As shown in Figure 2, be system construction drawing of the present invention, show general structure of the present invention, relation between correlation between each module and software of the present invention and the levels interface, as can be seen from Figure 2, the system that realizes adaption layer function in ATM switch that the present invention carried is shared out the work and help one another by a plurality of modules and finishes, though it is separate between each module, but by the virtual connections table, public visit objects such as buffer queue carry out information exchange, coordinate, wherein, thick line is represented the initialization process process, the gray line representative sends segmentation process, dotted line representative reorganization receives processing procedure, high-level interface comprises transmission interface (1a) in (promptly high-rise) (10), initialization interface (1b), receiving interface (1c) and connection management interface (1d), wherein initialization interface (1b) is provided by initialization module (201), be used for variable, data structures etc. are carried out initialization process, and operand comprises the virtual connections table, buffer queue, the verification factor table, transmit queue and some its dependent variables; Connection management interface (1d) is provided by connection management module (202), is used for foundation, the dismounting of virtual connections, and obtains operations such as virtual connections statistical information, and operand is the virtual connections table; Transmission interface (1a) provides by sending administration module (203), is used for a packet is carried out the operation of CS layer and the SAR layer of AAL5 by the virtual connections of appointment, and operand comprises virtual connections table, verification factor table, transmit queue and buffer queue; Receiving interface is provided by receiving processing module (205), packet that is used to submit to and additional information, and operand comprises virtual connections table, verification factor table and buffer queue; Segment processing module (204) is inserted mouthful (2a) remittance physical layer cell flow from the cell of following layer interface (bottom) (20), and operand comprises transmit queue, buffer queue; Reorganization operational module (206) extracts mouthful (2b) by cell and extracts cell, whether the virtual connections of checking the VPI/VCI correspondence of header exists, whether recombinate with decision, AUU indication according to header reassembles into CPCS-PDU, handing-over is received processing module (205) and is handled, and operand comprises buffer queue, virtual connections table.

As shown in Figure 3, the operating process of initialization module is for to carry out initialization process (step 301) to virtual connections table, buffer queue, transmit queue, check factor table etc.

As shown in Figure 4, the operating process of connection management module is divided into flow process a and flow process b, and the concrete operations of flow process a check at first for setting up virtual connections whether connection corresponding in the virtual connections table exists (step 401a), if exist, then return virtual connections and set up failure information (step 404a); If there is no, then operate the virtual connections table, connect (step 402a) returns virtual connections and sets up successful information (403a),

The concrete operations of flow process b check at first for removing virtual connections whether connection corresponding in the virtual connections table exists (step 401b), if existed, then return virtual connections and remove failure information (step 404b); If there is no virtual connections is then operated the virtual connections mark and is removed virtual connections (step 402b), returns virtual connections and removes successful information (403b).

As shown in Figure 5, the concrete operations step that sends processing module comprises: at first, check whether connection corresponding in the virtual connections table has existed (step 501), if exist, then judge the required buffer memory of transmit operation whether enough (step 502), if it is enough, then the distribute data buffer memory is added into the CPCS-PCU afterbody by input parameter, and the calculation check sequence, form CPCS-PDU, and add transmit queue (503), return and set up successful information (step 504), if corresponding connection does not exist in the virtual connections table, when perhaps the required buffer memory of transmit operation is not enough, all to returns and send failure information (step 505).

As shown in Figure 6, the concrete operations step of segment processing module comprises: the beginning segment processing, at first, judge whether transmit queue is empty (step 601), if be empty, the flow process of then returning this module begins, and restarts segment processing; If transmit queue is not empty, then from CPCS-PDU, read 48 bytes in order, and adjust read pointer to corresponding state (602), then, judge whether to arrive CPCS-PDU afterbody (step 603), if, then by specifying VPI/VCI to add header, and establish AUU=1, insert a mouthful remittance cell from cell, and give back buffer memory (step 604); If do not arrive the CPCS-PDU afterbody, then, establish AUU=0 by specifying VPI/VCI to add header, insert mouth from cell and import cell (step 605).

As shown in Figure 7, the processing module flow process that begins to recombinate at first judges whether to have received cell (701), if do not have, then the program of getting back to begins, and waits for receiving new cell; If received cell, check then whether connection corresponding in the virtual connections table exists (step 702), if there is no, then abandon this cell (703), wait receives new cell, if there is corresponding connection in the virtual connections table, then judges whether to have distributed buffer memory (step 704), if not, distribute data buffer memory (705) then; If then the judgment data bag adds this cell length, overlength (step 706) whether is if overlength is then given back this metadata cache (707); If overlength not, the payload that then will receive cell deposits (step 708) in the buffer memory in, judges whether last cell (step 709) when pre-treatment, if, give receiving processing module (710) with the CPCS-PDU that receives, if not, then judge whether to receive new cell (701).

As shown in Figure 8, the operating process of beginning receiving processing module is at first judged whether success (step 801) of CPCS-PDU verification, if information such as LI, UU, CPI are then extracted in success, hands in layer together with the CPCS-PDU payload and handles (step 802); If verification is unsuccessful, then abandon this CPCS-PDU, discharge metadata cache (803).

Claims

1, a kind of system that realizes adaption layer function in ATM switch is characterized in that this system comprises at least:

The virtual connections table of initialization process is carried out in the utilization of described connection management module through described initialization module, set up and remove virtual connections, described transmission processing module is sent to cell through transmit queue with cell and inserts mouth, described segment processing module is inserted a mouthful remittance physical layer cell from described cell, again cell is delivered to cell and extracted mouth, described reorganization processing module is extracted a mouthful extraction cell from described cell, indication is recombinated according to header, and described receiving processing module receives the result of described reorganization processing module.

2, the system that realizes adaption layer function in ATM switch as claimed in claim 1 is characterized in that the described initialization interface that described initialization module provides, and is used to handle the initialization of virtual connections table, metadata cache, verification sequence table data.

3, the system that in ATM switch, realizes adaption layer function as claimed in claim 1, it is characterized in that the receiving interface that described receiving processing module provides, according to Frame Check Sequence check CPCS-PDU, and the information of the extraction CPCS-PDU afterbody domain of dependence, hand in layer together with packet and handle.

4, a kind of method that realizes adaption layer function in ATM switch is characterized in that comprising at least following steps:

At first variable, data structure are carried out initialization process;

Foundation and dismounting to virtual connections manage;

For the upper strata provides packet;

Judge whether to exist the connection that can send;

Whether CPCS-PDU is correct in check; And

5, the method that realizes adaption layer function in ATM switch as claimed in claim 4 is characterized in that whether described verification Convergence Sublayer protocol data bag CPCS-PDU correctly comprises according to Frame Check Sequence is tested.

6, the method that in ATM switch, realizes adaption layer function as claimed in claim 4, it is characterized in that, described segment processing comprise when read pointer when assembling the afterbody of sublayer protocol data bag CPCS-PDU, by specifying VPI/VCI to add header, if AUU=1, insert a mouthful remittance cell from cell, and give back buffer memory.

7, the method that in ATM switch, realizes adaption layer function as claimed in claim 4, it is characterized in that, described segment processing comprise when read pointer not when assembling the afterbody of sublayer protocol data bag CPCS-PDU, by specifying VPI/VCI to add header, if AUU=0 inserts a mouthful remittance cell from cell.

8, the method that realizes adaption layer function in ATM switch as claimed in claim 4 is characterized in that, described reception flow process comprises when the CPCS-PDU verification succeeds, extracts LI, UU, and CPI information is handed in layer together with the CPCS-PDU payload and is handled.

9, the method that realizes adaption layer function in ATM switch as claimed in claim 4 is characterized in that, described reception flow process comprises when the CPCS-PDU verification is unsuccessful, abandons this CPCS-PDU, gives back metadata cache.