CN100461750C

CN100461750C - ATM signal-element-group bag and bag buffer storage management method

Info

Publication number: CN100461750C
Application number: CNB2005100372715A
Authority: CN
Inventors: 慕光; 伊学文
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-09-12
Filing date: 2005-09-12
Publication date: 2009-02-11
Anticipated expiration: 2025-09-12
Also published as: CN1852223A

Abstract

The method includes following steps: (1) if determining the current cell is a head cell, then applying for a basic buffer and an additional space, and writing payload of current cell to starting location of basic buffer; (2) if determining the current cell is a middle cell, then determining whether sequence number of current cell is larger than 32; (3) if sequence number of current cell is smaller than or equal to 32, then writing current cell to basic buffer; if sequence number of current cell is larger than 32, then writing current cell to additional space. Through providing additional space for basic buffer, the invention stores control information to buffer under precondition of not changing bursting operation characters of external memory space, and not changing procedure for processing whole message. Thus, the invention supports ATM frame with cells more than 32.

Description

The bag buffer storage management method of ATM cell group bag

Technical field

The present invention relates to communication field, particularly a kind of bag buffer storage management method of ATM cell group bag.

Background technology

, will carry out the group job contract of ATM cell usually and do in the conversion communication equipment of IP or Ethernet at various ATM, the structure of this cell group packet portion as shown in Figure 1.Group bag module 11 is used for safeguarding based on PVC (permanent virtual connection, the permanent virtual connection) group bag chained list, and after group bag is finished, frame control information is passed to subordinate's module, wherein frame control information comprises: the length of ATM frame, this frame be the buffer address etc. of storage device for storing externally.Group bag module 11 is also applied for buffer memory (be buffer, be meant the fundamental space of an ATM frame of storage herein, capacity is the 2k byte) to free buffer administration module (FBM) simultaneously, and cell is write corresponding external memory (for example DDRSDRAM) in order.Bag editor module 15 is used for reading the cell of external memory, to carry out the editor of message.In Fig. 1, the handling process of cell is as follows: at first the cell from ATM is input to group bag module 11, and this group bag module 11 will be based on the cell reorganization of PVC.Group bag module 11 passes to bag editor module 15 to the control information of whole ATM frame (FCI) via other processing module 13 after having organized bag, bag editor module 15 is read the bag data and is handled again according to message length in the frame control information and buffer address from external memory.After bag editor module 15 disposes, discharge and be cached to free buffer administration module 14.

Generally in above-mentioned conversion communication equipment, allow a plurality of PVC links when handling cell group bag, and allow the cell between the PVC to interweave.Therefore cell group bag method is usually: after receiving a cell, obtain the PVC index and whether be first cell according to the information of header, if first cell is then applied for a new bag buffer memory (a basic buffer memory is the 2k byte), and in the cell payload 48 byte write storage devices; If intermediate cellular is then read the bag buffer memory base address and the offset information (sequential counting of cell) of preservation from group bag chained list, equally cell is written in the external memory.

Consider the read-write efficiency and the burst operation problem of storage device, existing method generally is fritter (Block) space that the cell payload of one 48 byte directly takies 64 bytes, and the cell of same PVC is deposited in the fritter of same basic buffer memory in order.Promptly the buffer memory of a 2k byte can be divided into 32 fritters continuously.As shown in Figure 2, dash area is exactly the actual idle space of each fritter: the 64-48=16 byte.Similarly, at the bag editor module 15 of read storage device data side, the regular length read method of 64 bytes of also taking to happen suddenly is only got the valid cell payload of front 48 bytes.Like this, the read-write storage device has all adopted the operation of regular length, has improved the utilance and the bag read-write processing speed of storage device.

According to said method,, can support that an ATM frame the longest is 32 cell payloads, i.e. 32 x 48=1536 bytes at the cell input side.

As preceding description, existing cell caching method can only be supported maximum 1536 bytes.If surpass the ATM frame of 1536 bytes, existing method just can't meet the demands.If simple big or small double a basic buffer memory that is responsible for assigning, the storage device capacity that then expends is supported under the situation of multiple pvcs especially at the same time with double.As supporting the PVC of 2k, want 2k x 2k byte=4M bytes of memory device at least; If basic fritter is expanded into the 4k byte, total capacity will be the 8M byte, and the utilance of storage device is not high yet, is unfavorable for the expansion of number of connection simultaneously.

Summary of the invention

The objective of the invention is to, a kind of bag buffer storage management method of ATM cell group bag is provided, solve and waste memory space, the difficult problem that expands of number of connection in the bag buffer storage management method that has ATM cell group bag now.

Technical scheme of the present invention is, a kind of bag buffer storage management method of ATM cell group bag is provided, and may further comprise the steps:

(a) if judge that current cell is a cell, then apply for a basic buffer memory and an additional space, and current cell payload is write the original position of basic buffer memory;

(b) if judge that current cell is an intermediate cellular, whether the serial number of then judging described current cell is greater than 32;

(c) if the serial number of current cell is less than or equal to 32, then current cell is write basic buffer memory; If the serial number of current cell then writes additional space with current cell greater than 32.

In the bag buffer storage management method of above-mentioned ATM cell group bag, further comprising the steps of in the step (c):

(c1) judge according to the header of current cell whether current cell is the most last cell of ATM frame, if current cell is the most last cell, then according to all cell memory location delta frame control informations, and described frame control information is delivered to the bag editor module, described frame control information comprises the externally buffer address in the storage device of the length of ATM frame and described ATM frame.

In the bag buffer storage management method of above-mentioned ATM cell group bag, after step (c), also comprise the step that reads the cell of basic buffer memory and additional space stored according to described frame control information.

In the bag buffer storage management method of above-mentioned ATM cell group bag, the ATM frame at described current cell place comprises 32+n cell, and wherein n is the integer more than or equal to 1.

In the bag buffer storage management method of above-mentioned ATM cell group bag, the basic cache size in the step (a) is 32 * 64 bytes, and the additional space size is n * 64 bytes.

In the bag buffer storage management method of above-mentioned ATM cell group bag, also be included in the step of safeguarding after basic buffer memory of described application and the additional space based on the group bag chained list of PVC (permanent virtual is connected) in the step (a).

In the bag buffer storage management method of above-mentioned ATM cell group bag, current cell described in the step (c) writes the position of basic buffer memory and determines according to the base address of basic buffer memory in the described group of bag chained list and the side-play amount of current cell.

In the bag buffer storage management method of above-mentioned ATM cell group bag, described basic buffer memory and additional space are associated by pointer.

The bag buffer storage management method of ATM cell group bag of the present invention, by providing additional space for basic buffer memory, realized under burst operation characteristic that does not change external memory space fully and whole message processing procedure prerequisite, the buffer memory control information, thus support surpasses the ATM frame of 32 cells.

Description of drawings

Fig. 1 is the structured flowchart of the device of ATM cell group bag;

Fig. 2 is the existing schematic diagram deposited of ATM frame in buffer memory;

Fig. 3 is the flow chart of group bag in the bag buffer storage management method of ATM cell group bag of the present invention.

Embodiment

As shown in Figure 3, be the flow chart of group bag in the bag buffer storage management method of ATM cell group bag of the present invention.In the present embodiment, suppose to be long bag that its length is 33 cells, i.e. 33 * 48=1584 byte from the ATM frame of cell outlet side input.At first, group bag module 11 receives the cell (step S31) of input from atm device, obtains PVC (permanent virtual connection) index (step S32) from the header information of input, and judges cell (step S33) headed by current cell whether according to header information.In the present embodiment, header information comprises the sequential scheduling control information of cell in the ATM frame.

If cell headed by the current cell, then group bag module 11 is arranged in the new basic buffer memory (size is the 2k byte) of external memory 12 to 14 one of the application of free buffer administration module, distribute an additional space (length of this additional space is a fritter, i.e. 64 bytes) for this basic buffer memory simultaneously; Safeguard group bag chained list (step S34) according to the basic buffer memory that distributes and additional space then, and current cell payload 48 bytes are written to external memory (can be DDRSDRAM) (step S35) based on PVC (permanent virtual connection).In the present embodiment, a basic buffer memory is divided into 32 fritters, and each fritter is 64 bytes, and a cell occupies a fritter.In the present embodiment, group bag chained list comprises: whether cell is the sign of a first cell of bag; Cell is the storage base address and the side-play amount of buffer memory externally, i.e. the serial number of cell in current bag.

If current cell is not first cell, then group bag module 11 further reads the group bag chained list of current cell, obtain the bag buffer memory base address and the offset information (being the sequential counting of cell) (step S36) of current cell, and whether the serial number of judging current cell be 33, and promptly whether the basic buffer memory of Fen Peiing writes full (step S37).If the serial number of current cell is non-32, then current cell is write in the external memory 12, return step S31 then, carry out the processing of next cell; If the serial number of current cell is 33, last cell that promptly current cell is the ATM frame then is written in current cell the additional space (step S38) of the basic buffer memory that distributes among the step S34.

After all cell group bags are finished, group bag module 11 generates the frame control information (the base address information of the basic buffer memory that record frame length, frame are deposited) of current ATM frame, and with this frame control information via other processing module 13 be transferred to the bag editor module 15, this frame control information comprises the externally buffer address (step S39) deposited of memory device of the length of ATM frame and this frame, finishes writing of an ATM frame.

Similarly, when bag editor module 15 read cell from storage device 12, the frame control information according to from group bag module 11 read cell from basic buffer memory and additional space successively.After all data (cell) of an ATM frame read successfully, discharge the buffer memory that this ATM frame occupies by free buffer administration module 14.

In another embodiment of the present invention, the length of ATM frame also can be 34 (34 * 48=1632 bytes) or the cell more than 34.In this embodiment, similar with the embodiment of Fig. 3, when application bag buffer memory, be two or more continuous fritters just for the additional space of each basic buffer memory application, the size of each fritter is 64 bytes.It also is additional space behind the earlier basic buffer memory that cell reads process.

Among the aforesaid embodiment, it is under the prerequisite of burst operation characteristic that does not change external memory fully and whole message processing procedure, the buffer memory control information under the capacity situation that increases very little outside storing apparatus buffer memory, can conveniently support to surpass the ATM frame of 32 cells.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims

1. the bag buffer storage management method of an ATM cell group bag is characterized in that, may further comprise the steps:

(a) if judge that current cell is a cell, then apply for a basic buffer memory and an additional space, and current cell payload is write the original position of basic buffer memory; Described basic cache size is 32 * 64 bytes, and described additional space size is n * 64 bytes, and wherein said n is cell number and 32 a difference in the ATM frame at described current cell place, and described n is the integer more than or equal to 1;

2. the bag buffer storage management method of ATM cell group bag according to claim 1 is characterized in that, and is further comprising the steps of in the step (c):

3. the bag buffer storage management method of ATM cell group bag according to claim 2 is characterized in that, also comprises the step that reads the cell of basic buffer memory and additional space stored according to described frame control information after step (c).

4. the bag buffer storage management method of ATM cell group bag according to claim 1 is characterized in that, also is included in the step of safeguarding the group bag chained list that is connected based on permanent virtual after basic buffer memory of described application and the additional space in the step (a).

5. the bag buffer storage management method of ATM cell group bag according to claim 4, it is characterized in that current cell described in the step (c) writes the position of basic buffer memory and determines according to the base address of basic buffer memory in the described group of bag chained list and the side-play amount of current cell.

6. the bag buffer storage management method of ATM cell group bag according to claim 1 is characterized in that, described basic buffer memory and additional space are associated by pointer.