WO2008031296A1

WO2008031296A1 - A judgement handling method for sequence number of sequenced data in service specific connection oriented protocol

Info

Publication number: WO2008031296A1
Application number: PCT/CN2006/003806
Authority: WO
Inventors: Dianxiong Hu; Pei Fan; Zesheng Zhao
Original assignee: Zte Corporation
Priority date: 2006-09-11
Filing date: 2006-12-31
Publication date: 2008-03-20
Also published as: CN101146024A

Abstract

A judgement handling method for sequence number of sequenced data in service specific connection oriented protocol, after sequenced data (SD) received by receivers, judges according to the sequence number of sequenced data (SD.N(S)) and value of based variable of SSCOP and deals with the SD based on the judgement, in process of judgement and handling, judges whether the SD.N(S) smaller than the sequence number (VR(R)) of the next data pack that in expectation of receiving by receiving window, if yes, discards said SD, ends, if no, goes on the following judgement and handling.

Description

TECHNICAL FIELD The present invention relates to a processing method for a service specific connection-oriented protocol SSCOP (SERVICE SPECIFIC CONNECTION ORIENTED PROTOCOL) in an asynchronous transmission mode ATM signaling network. In particular, when the link is in the service state, the SS method is used in the SSCOP protocol layer for the sequenced data SD (Sequenced Data) sequence number. BACKGROUND When a third generation mobile communication system uses ATM technology as a terrestrial transmission bearer, SSCOP is used on the Iu interface between the core network CN and the radio network controller RNC, the lub interface between the RNC and the base station NodeB, and the Iur interface between the RNCs. The protocol performs reliable transmission of signaling data.

The SSCOP protocol is responsible for the transmission of information and control information between two peer-to-peer entities. The upper layer provides services for the service-specific coordination function layer SSCF, and the lower layer interacts with the common part of the ATM adaptation layer, the sub-layer AAL CPCS.

The SSCOP protocol is defined by the international communication standard ITU-T Q.2110 and provides the following functions: Sequence integrity: Ensures that the transmitted SDCOP SD protocol data unit PDUs are in the same order; Error retransmission: The SSCOP entity at the receiving end is detecting the missing SSCOP service data. When the unit SDU is used, the retransmission mechanism is used for error correction. Flow control: adjust the transmission rate to adjust the transmission window for flow control; report error to LM: report error to LM; keep link activated: two peers The SSCOP entity can remain connected for a period of time without data transmission. Local data retrieval: When the link switching occurs on the upper layer, the local SSCOP user can retrieve the SDU that is not released by SSCOP. Connection Control: This function includes SSCOP. Connection establishment, release, synchronization, and undefined transmission of user-to-user messages to users of different lengths; Data transfer: Transfer of user data between SSCOP users and support both deterministic and non-deterministic data transfers; Protocol error recovery: Detection and recovery of protocol operational errors; Status report: Exchange of status information between sending/receiving peers . The basic variables of the SSCOP protocol are described below:

VR(R): The serial number of the next expected SD PDU, plus 1 after receipt.

VR(H): The next largest SD PDU that is expected to be received, updates VR(H) when a new SD PDU or POLL PDU is received.

VR(MR): The maximum number of SD PDUs allowed to be received. N(S) : The serial number of the current SD PDU. In the data transmission phase, when the receiver receives the SD sent by the peer, and SD.N(S) is less than VR(R), the processing steps according to the protocol are as shown in Figure 1:

1. Determine whether the SD falls within the upper boundary of the receive window WinLen by judging the statement "SD.N(S)< VR(MR)". At this point, the judgment statement is "true", proceed to the next step; 2. Determine whether the SD is the next SD that the local end expects to receive, by the expression SD.N(S)=

VR(R) judges, at this time, the judgment result is to proceed to the next step;

3. When performing cache processing, first check whether the receive buffer is valid, that is, check if the receiver has enough receive buffer space to save the SD. If not, discard the SD and end the processing; assuming that there is enough buffer space at this time, proceed to the next step; 4. Determine whether the serial number of SD is equal to VR(H), at this time, the judgment result is "false" , proceed to the next step

5. Determine whether the serial number of SD is greater than VR(H). Since the serial number of SD is less than VR(H), proceed to the next step;

6. Check whether there is SD with the same serial number in the receiving buffer. If it exists, protocol error processing is performed. Otherwise, it is ready to save to the receiving buffer. It is assumed that there is no serial number in the buffer. SD, enter ^" next step - step;

7. Save the SD to the receive buffer and end processing. Through the above steps, if the receiver receives the SD sent by the peer and satisfies SD. N(S) < VR(R), the SD will be saved by the receiver in the receiving buffer of the receiver, but according to When the protocol receiver extracts the data of the receive buffer and sends it to the upper-layer user, the serial number of the SD stored in the buffer must be greater than the current receiver's VR(R). Therefore, this SD is stored in the receive buffer. Cannot be taken out and sent to the upper layer user. As a result, the receiving side receives buffer confusion and the upper layer service is abnormal. The chaotic situation can be seen in Figure 2:

(1) After receiving the out-of-order SD1, save SD1 in the buffer; (2) SD2 is transmitted to the upper-layer user as the system runs;

(3) As the system runs, the out-of-order SD1 originally saved in the buffer falls back into the receiving window, and there are VR(R)=SDl. N(S) -1 , VR(H)> VR( R), at this time, receiving the SD sent from the opposite end, there is SD. N(S) = VR(R);

(4) After the SDCOP layer forwards the SD to the upper layer service layer, the SSCOP processing process increments VR(R) by 1, and then finds whether there is an SD with the sequence number equal to VR(R)+1 in the receive buffer, and SD1 will It was successfully submitted to the upper layer of the business layer, but this is the SD1 with the serial number NS, not the correct SD that the user needs. The principle of order consistency that is followed when the SSCOP protocol forwards data violates the business exception, causing the receiver to receive buffered data. As can be seen from the above description: In the case where the serial number of the received SD is less than VR(R), the SSCOP ten is not handled properly, and needs to be modified. The technical problem to be solved by the present invention is to propose a service specific aspect. The method for judging the ordered data sequence number in the connection protocol. In the data transmission phase, when the receiver receives the SD sent by the peer, and SD.N(S) is less than VR(R), the receiver can be avoided. In order to solve the above technical problem, the present invention proposes a method for judging ordered data numbers in a service-specific connection-oriented protocol, and after receiving the ordered data SD, the received data is based on the ordered data. Serial number The values of the SD.N(S) and SSCOP protocol basic variables are judged and the SD is processed according to the judgment result, and the method further includes: determining the ordered data serial number SD, N(S) in the determining and processing process. Whether it is smaller than the sequence number VR(R) of the next expected packet received in the receiving window, if yes, discard the SD and end, otherwise continue the subsequent judgment and processing. Further, the above method may also have the following features: After receiving the ordered data SD, the receiver performs the following judgment and processing:

(a) Determine its serial number SD.N(S): If SD.N(S) is greater than or equal to the maximum sequence number VR(MR) of the packet to be received, discard the SD and end; if SD.N(S) Equal to the sequence number VR(R) of the expected received packet, send it to the upper layer service and check the receive buffer, send the legal data to the service layer, and end; if SD.N(S) is less than VR (R), discarding the ordered data, ending; if SD.N(S) is greater than VR(R) and less than VR(MR), performing step (b);

(b) Check if there is enough space in the receive buffer to save the SD, if not, end, otherwise, proceed to step (c);

(c) determining whether SD.N(S) is equal to or greater than the maximum sequence number VR(H) of the ordered data that is expected to be received, and if so, saving the SD in the buffer; otherwise, performing step (d);

(d) Determine whether there is the SD with the same serial number in the receive buffer. If yes, do the protocol error recovery processing with the error type Q. Otherwise, save the SD in the buffer. Further, the above method may further have the following features: In the step (a), SD.N(S) is smaller than

VR( ), performs protocol error recovery processing with error type Q, and ends. Further, the above method may also have the following features: In the step-猓(a), when SD.N(S) is greater than VR(MR), check whether the local end has received lost space, and if so, to the opposite end Send an unsolicited status PDU, if not, end the process. Compared with the prior art, the present invention increases the judgment process of whether the serial number of the SD is greater than the lower boundary VR(R) of the receiving window in the data transmitting phase, and if the serial number of the SD is smaller than the lower boundary of the receiving window, Therefore, it is necessary to take measures and not save it in the receiving buffer of the receiver, thereby avoiding the receiving buffer buffer confusion and the upper layer service being abnormal. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a process after receiving an SD in the prior art. FIG. 2 is a schematic diagram of the receiving buffer confusion caused by the processing flow of FIG. 1. FIG. 3 is a flow chart showing the processing of the SD serial number in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 3, based on the original processing of the SD serial number, the determination process of the SD serial number and the lower boundary of the receiving window VR(R) is added. The specific steps are as follows: Step 110: Determine whether SD.N(S) is smaller than VR (MR), that is, whether the SD is within the upper boundary of the receiving window WinLen. If yes, go to step 120; otherwise, discard the SD and check whether the local end has received the lost space. If yes, send the USTAT PDU to the peer. If not, the process ends. Step 120 It is judged whether the SD is the next SD that the terminal expects to receive, that is, whether SD.N(S) is equal to VR(R), and if it is "true", the SD is sent to the upper layer service and the receiving buffer is checked. And sending the legal data to the service layer, and ending, otherwise, performing step 130; Step 130, determining whether the serial number of the SD is greater than VR(R), that is, determining whether the SD falls within the lower boundary of the receiving window, if the description is If the data is out of order, the SD is discarded, and the protocol error recovery processing of the error type Q is performed, and the process ends. Otherwise, step 140 is performed; the protocol error recovery processing of the error type Q is performed in the protocol, and the data transfer timer reset data transfer is first reset. Timer, then sends MAA_ERROR-indication(Q) to the layer management, and finally performs error recovery processing. Step 140: Check whether there is enough space in the receiving buffer to save the SD. If it is "false", discard the SD and end. Otherwise, go to step 150. Step 150, determine whether the serial number of the SD is equal to VR (H). ), if it is "true", save the SD in the buffer, otherwise, proceed to step 160; Step 160: Determine whether the serial number of the SD is greater than VR(H). If it is "true", save the SD in the buffer. Because a new lost interval is generated, an unsolicited status PDU needs to be sent to the opposite end to notify the opposite end. If the received data is lost, the requesting end retransmits; otherwise, step 170 is performed; Step 170, determining whether the SD is in the receiving buffer, that is, checking whether there is an SD with the same serial number in the receiving buffer, if "True", do the protocol error recovery processing with the error type Q, otherwise, save the SD in the buffer. In another embodiment, if the sequence number SD.N(S) of the SD received by the step 130 is less than VR(R), the SD is discarded, and the protocol error recovery process of the error type Q is not performed, and the process ends. In other embodiments, the step 130 determines whether the serial number of the SD is greater than VR(R), and after placing the SD, checks whether there is any space in the receiving buffer before there is enough space; and steps 110 and 120 The order can be changed.

Claims

A method for judging the ordered data sequence number in a service-specific connection-oriented protocol, after receiving the ordered data SD, the receiver determines and according to the value of the ordered data sequence SD.N(S) and the SSCOP protocol basic variable The judgment result is correspondingly processed to the SD, and the method further includes: determining whether the ordered data sequence number SD.N(S) is smaller than a sequence number VR of the next expected data packet in the receiving window. (R), if yes, discard the SD and end, otherwise continue the subsequent judgment and processing.

Right

The method according to claim 1, wherein: after receiving the ordered data SD, the receiving party performs the following judgment and processing:

(a) determine its serial number SD.N(S):

If SD.N(S) is greater than or equal to the maximum sequence number VR(MR) of the data packet that is allowed to be received, discard the SD and end;

If SD.N(S) is equal to the sequence number VR(R) of the packet to be received, it is sent to the upper layer service and checks the receiving buffer, and the legal data is sent to the service layer, ending; if SD. If N(S) is less than VR(R), the ordered data is discarded, and the process ends;

If SD.N(S) is greater than VR(R) and less than VR(MR), perform step (b);

(b) Check if there is enough space in the receive buffer to save the SD, if not, end, otherwise, perform step (c);

(c) determine whether SD.N(S) is equal to or greater than the maximum sequence number VR(H) of the ordered data that is expected to be received, and if so, save the SD in the buffer; otherwise, perform step (d);

(d) judging whether there is the SD with the same serial number in the receiving buffer, and if so, doing the protocol error recovery processing with the error type Q, otherwise, saving the SD in the buffer. The method of claim 1 or 2, characterized by:

In the step (a), SD.N(S) is smaller than VR(R), and the protocol error recovery processing of the error type Q is performed, and the process ends. The method of claim 2 wherein:

In the step-by-step (a), when SD.N(S) is greater than VR(MR), check whether the local end receives Lost space, if any, sends an unsolicited status PDU to the peer, if there is no 'end processing.