CN100479412C

CN100479412C - Method and device for dispatching permanent virtual path

Info

Publication number: CN100479412C
Application number: CNB2007101037501A
Authority: CN
Inventors: 王彬; 林晖; 刘强
Original assignee: Hangzhou H3C Technologies Co Ltd
Current assignee: New H3C Technologies Co Ltd
Priority date: 2007-05-22
Filing date: 2007-05-22
Publication date: 2009-04-15
Anticipated expiration: 2027-05-22
Also published as: CN101051988A

Abstract

The method comprises: dividing the PVCs to be scheduled into N groups (N is natural number and >1); during each cell-transmitting cycle, making the polling for said N groups of PVC in order to select a group of PVCs; selecting one of the selected PVCs as the currently-served PVC; sending out the cell of currently-served PVC.

Description

A kind of method and apparatus of dispatching permanent virtual path

Technical field

The present invention relates to data communication technology field, refer to the method and apparatus of a kind of dispatching permanent virtual path (PVC, Permanent Virtual Channcl) especially.

Background technology

According to traffic management (TM, Traffic Management) standard 4.1 editions, asynchronous transfer mode (ATM, Asynchronous Transfer Mode) mainly comprises following a few class for the data asynchronous transmission service that the user provides:

Constant bit rate (CBR, Constant Bit Rate) service, bit is transferred to the other end with constant speed from an end in this service, does not have error detection in the transmission course, and other operations such as flow control are mainly used to analog circuit and exchange, as the T1 circuit etc.

Variable bit rate (VBR, Variable Bit Rate) service, such service is divided into two subclasses again, be respectively real-time variable bit rate (RT-VBR, Real Time Variable Bit Rate) and Non-Real Time Variable Bit Rate (NRT-VBR, Non-Real Time Variable Bit Rate).RT-VBR is mainly used to provide has the strict variable bit rate service that requires in real time, and as real-time video conference etc., in this class service, atm network can not be introduced fluctuation in the transmission of cell, because this can cause the fluctuation of demonstration.And in the NRT-VBR service, transmission in time is very important, but can tolerate a certain amount of shake in using, as rich email.

Available Bit Rate (ABR, Available Bit Rate) service, such service mainly are for the design of communication of the uncertain burst type of bandwidth, as, what use when the user uses Web browser to come Query Information is such service.At this moment, the user is uncertain to the needs of bandwidth, if the user is when the continuous homepage of visit data amount and user are reading current homepage, needed bandwidth seldom, and is almost nil; And when the intensive homepage of user's download image, required bandwidth can increase sharply.Use the ABR service, can make the user avoid applying for for a long time a fixed-bandwidth, for example, the user can be appointed as own used virtual connections: under usual condition, bandwidth is 2Mbps, the 10Mbps but bandwidth can raise.In the ABR service, when network takes place to block, can return the message that request slows down transmission to information transmitter, ABR is unique a kind of COS with feedback mechanism.

Indefinite bit rate (UBR, Unspecified Bit Rate) service, this class service is not made any promise to the user, network congestion is not made any feedback yet.When network takes place when congested, the UBR cell will be dropped, and network can not return any feedback information to the sender.Use the UBR service can realize information services such as file transfers, Email and billboard.

At present, the ATM outbound port bandwidth of ATM system support can reach 622Mbps, and needs to support 1k bar PVC, i.e. 1024 Permanent Virtual Path PVC, every PVC can random arrangement becomes any one among UBR, RT-VBR, NRT-VBR, the CBR, and the minimum particle size of professional transmission rate is 64kbps.

In the prior art, the employing polling mechanism is realized the scheduling to 1k bar PVC, its implementation be from 1k PVC cell-queue according to certain decision operation, poll goes out the current PVC cell-queue that needs scheduling to send, and the cell in this formation is sent.

Fig. 1 is the schematic diagram of scheduling PVC in the prior art.As shown in Figure 1, processing module 103 in the scheduler module 102,1k bar PVC in each snoop queue administration module 101, therefrom select a current PVC who needs most scheduling, and the identification information of this PVC sent in the transmit queue 104, outlet module 105 reads the identification information of PVC successively from transmit queue 104, the cell of the PVC that reading identification information is identified sends.

But, when adopting polling mechanism shown in Figure 1, whenever to finish a cell transmission and need carry out the PVC query actions 1k time, this needs 1k clock cycle at least, and promptly 1k claps.Therefore, under 156M dominant frequency clock, per second sends 156M/1k=156k cell, an ATM cell comprises 53 bytes, therefore each byte 8 bit adopts the described polling mechanism of Fig. 1, and maximum can only reach per second 156k * 53 * 8 bits, approximate the ATM outbound port transmission rate of 64.5Mbps, far can not realize the transmission rate of ATM outbound port 622Mbps.According to poll PVC scheduling mode shown in Figure 1, want to reach the outbound port processing bandwidth of 622Mbps, per second need send the individual cell of 622M/ (53 * 8), then under 156M dominant frequency clock, 156M/ (622M/ (53 * 8))=106.3 claps will send a cell, clap the intact PVC of poll by each and calculate, can only realize also that at most the scheduling of 106 PVC sends.

As seen, the scheduling mechanism of all PVC of poll successively of the prior art is dispatched than multiple pvcs at needs, under the situation as 1k bar PVC, its outbound port speed is lower, and maximum can only reach 64.5Mbps, also far can not reach the supported 622M bandwidth of present atm device outbound port; If want to reach the outbound port speed of 622M, mechanism by polling dispatching PVC of the prior art, can only dispatch 106 PVC at most, also far can not reach the present scheduling multiple pvcs that needs, system requirements specification as 1k bar PVC, therefore, the service quality of atm network (QoS, Quality of Service) is lower.

Summary of the invention

In view of this, the present invention mainly provides the method for a kind of PVC of scheduling, and this method makes atm network under the situation that realizes the scheduling multiple pvcs, has higher outbound port speed, thereby has improved the QoS of atm network.

The present invention also provides the device of a kind of PVC of scheduling, and this device makes atm network under the situation that realizes the scheduling multiple pvcs, has higher outbound port speed, thereby has improved the QoS of atm network.

For achieving the above object, technical scheme of the present invention specifically is achieved in that

The invention discloses the method for a kind of PVC of scheduling, this method comprises:

All PVC to be scheduled are divided into the N group, and N is the natural number greater than 1;

In each cell transmission cycle, simultaneously N group PVC is carried out poll respectively, select a PVC at most among each group PCV from N group PVC, from all PVC that selected, select a PVC again as the current PVC that needs service, this current cell of the PVC of service that needs is sent.

The invention also discloses the device of a kind of PVC of scheduling, this device comprises: the queue management module, a N scheduler module and the outlet module that comprise N group PVC, wherein, N is the natural number greater than 1, and it is corresponding one by one that N sub-scheduler module and N in the queue management module organize PVC;

Each sub-scheduler module, be used for when each cell transmission cycle arrives, one group of corresponding with it in queue management module PVC is carried out poll, when having optional PVC among the PVC of poll, select a PVC, and the identification information of selected PVC is sent to outlet module;

Outlet module is used to receive the identification information of the PVC that sub-scheduler module sends, and selects a PVC as the current PVC that needs service from all PVC that all identification informations identified, and the cell among this current PVC that needs service is sent.

As seen from the above technical solution, of the present inventionly this PVC to be scheduled is divided into N group, N is greater than 1; And in each cell transmission cycle, simultaneously N group PVC is carried out poll, from N group PVC, select PVC, from all PVC that selected, select a PVC again as the current PVC that needs service, the technical scheme that this current cell that needs the PVC of service is sent, shorten the atm device poll and once remained to be dispatched the time of PVC, thereby accelerated the speed that atm device sends cell.Therefore, technical scheme of the present invention makes atm network under the situation that realizes the scheduling multiple pvcs, has higher outbound port speed, thereby has improved the QoS of atm network.

Description of drawings

Fig. 1 is the schematic diagram of scheduling PVC in the prior art;

Fig. 2 is the flow chart of the method for a kind of PVC of scheduling of the present invention;

Fig. 3 is the structured flowchart of the device of a kind of PVC of scheduling of the present invention;

Fig. 4 is the internal structure and the outside block diagram that is connected of the sub-scheduler module 1 among Fig. 3.

Embodiment

The present invention mainly by multiple pvcs to be scheduled is divided into groups, carries out the mode of graded dispatching then, at short notice multiple pvcs is realized a polling operation, has improved the efficient of PVC scheduling.

Fig. 2 is the flow chart of the method for a kind of PVC of scheduling of the present invention.As shown in Figure 2, may further comprise the steps:

Step 201 is divided into the N group with all PVC to be scheduled, and N is the natural number greater than 1.

In this step, preferably, PVC to be scheduled can be divided into fifty-fifty N group, promptly N the PVC number in dividing into groups is identical or roughly the same.

Step 202, in each cell transmission cycle, simultaneously N group PVC is carried out poll, from N group PVC, select PVC, from all PVC that selected, select a PVC again as the current PVC that needs service, this current cell of the PVC of service that needs is sent.

Preferably, in this step, to each group PVC when carrying out poll, can organize according to this and whether exist the PVC that meets scheduling transmission condition to come from this group PVC, to select a PVC among PVC.Simultaneously, when N group PVC is carried out poll, may not have the PVC that meets scheduling transmission condition in some the PVC group among the N group PVC, therefore the number of the PVC that selects from N group PVC may be less than N.

In this step, because N group PVC is carried out poll simultaneously, that has therefore improved carries out the speed of a poll to all PVC.

As seen, can improve the speed that poll once remains to be dispatched PVC, and then improve the speed that sends cell by above-mentioned steps.

Fig. 3 is the structured flowchart of the device of a kind of PVC of scheduling of the present invention.As shown in Figure 3, this PVC dispatching device comprises: the queue management module 301, scheduler module 302 and the outlet module 303 that comprise N group PVC.Wherein scheduler module 302 comprises N sub-scheduler module, is respectively: sub-scheduler module 1, and sub-scheduler module 2 ..., sub-scheduler module N, N be the natural number greater than 1, it is corresponding one by one that N sub-scheduler module and N in the queue management module organize PVC.

In the scheduler module 302 each sub-scheduler module, be used for when each cell transmission cycle arrives, one group of corresponding with it in the queue management module 301 PVC is carried out poll, when having optional PVC in the PVC of the poll group, select a PVC, and the identification information of selected PVC is sent to outlet module 303; Wherein, each sub-scheduler module can determine whether the PVC of its poll exists optional PVC in organizing by whether there being the PVC that meets scheduling transmission condition in the PVC group of determining its poll.

Outlet module 303, the identification information that is used for the PVC that the sub-scheduler module of each of receiving scheduling module 302 sends, and from all PVC that all identification informations identified, select a PVC as the current PVC that needs service, the cell among this current PVC that needs to serve is sent.

In the embodiment of the invention, after outlet module 303 was chosen the PVC that finally will serve, its mode that sends the cell of this PVC that chooses sent the mode of the cell of PVC with the outlet module among Fig. 1 105.

For making purpose of the present invention, technical scheme and advantage clearer, be 622M with ATM outbound port bandwidth below, need to support 1k bar PVC, every PVC can be configured to any one among UBR, RT-VBR, NRT-VBR, the CBR at random, the minimum particle size of professional transmission rate is that the system requirements specification of 64kbps is an example, and the present invention is described in more detail.

Consider that ATM cell comprises 53 bytes, each byte 8 bit (bit), in total transmission information 26/27 is ATM cell, 1/27 is other signaling consumptions, when the transmission rate of ATM outbound port reaches 622Mbps, send a required time of ATM cell and be: (53 * 8bit)/[622Mbps * (26/27)]=707.8ns, per second sends 1s/707.8ns cell, convert under the 156M dominant frequency, about 156M/ (1s/707.8ns)=110 sends and send a cell.

By the above-mentioned parameter calculation specifications, need only 1k PVC of poll in 110 clap, and therefrom select a PVC, the cell of this PVC is sent, the cycle that promptly sends a cell is 110 bats, just can make ATM outbound port speed reach 622Mbps, thereby realizes the QoS demand.Directly the minimum 1k that needs of 1k bar PVC polling dispatching is clapped in the prior art scheme, obviously can not satisfy the QoS demand, therefore, use Fig. 2 and PVC scheduling scheme shown in Figure 3:

At first, 1k bar PVC is divided into the N group.Clapping an interior sub-scheduler module 110 in theory at most can 110 PVC of poll, but needs the time overhead of other operations in addition in the middle of considering reality, and the convenience of calculating, and makes each sub-scheduler module that 64 PVC are carried out polling dispatching in the present embodiment.Therefore, N=1k/64=16 is about to 1k bar PVC and is divided into 16 groups, and every group comprises 64 PVC.This moment in Fig. 3, N=16, m=64, the 1k bar PVC in the queue management module 301 is divided into 16 groups, every group comprises 64 PVC.Secondly, in 110 clapped, 16 sub-scheduler modules among Fig. 3 in the scheduler module 302 were carried out poll respectively to 16 groups of PVC simultaneously, select PVC from 16 groups of PVC, and sent the identification information of selected PVC to outlet module 303.In the present embodiment, if all have the PVC that meets scheduling transmission condition in 16 PVC groups, then last, outlet module 303, the identification information of 16 PVC that 16 sub-scheduler modules in the receiving scheduling module 302 send, and from 16 PVC of identification information sign, select a PVC, the cell among this PVC is sent.At this moment, the transmission rate of the outlet module 303 of the device of scheduling PVC shown in Figure 3 can reach 622Mbps.As seen, in the present embodiment, the sub-scheduler modules of in the scheduler module 302 16 realize that 64 select 1 first order scheduling, and outlet module 303 realizes that 16 select 1 second level scheduling, thereby have realized in 110 clap the once scheduling to 1k bar PVC.

Next be described in detail in the detailed process how the foregoing description neutron scheduler module realizes first order scheduling and outlet module realization second level scheduling.

In the first order scheduling process of the embodiment of the invention, in order to realize the fairness dispatch between the PVC, leak bucket for the PVC of VBR, UBR and CBR business is provided with cell respectively, go up the professional maximum cell rate that can reach, i.e. Peak Cell Rate to limit a PVC; And for the PVC of VBR business further is provided with Token Bucket, to limit the average cell rate that a PVC goes up the VBR business, i.e. sustainable cell rate.

Be example with above-mentioned calculation of parameter result still, outbound port bandwidth (BAND) is 622Mbps, and PVC to be scheduled is the 1k bar, and a scheduler module comprises 16 sub-scheduler modules, and each sub-scheduler module is dispatched 64 PVC.At every PVC, the parameter that the user can dispose comprises: Cell Delay Variation Tolerance (CDVT, Cell Delay Variation Tolerance), Peak Cell Rate (PCR, Peak Cell Rate), sustainable cell rate (SCR, Sustainable Cell Rate) and Maximum Burst Size (MBS, Maxirnum Burst Size) etc.For CBR service needed configuration CDVT and PCR; The configuration of VBR service needed CDVT, PCR, parameters such as SCR, MBS; UBR service need not to dispose any parameter.

The CBR business sends cell with constant rate of speed in practice, and it is the highest at all professional medium priorities; Next is the RT-VBR business, the real-time that it is had relatively high expectations; Be the NRT-VBR business once more, it does not have the real-time requirement, as long as accomplish statistical average; At last for UBR service, it is the business that does not guarantee any service quality, only it just can obtain service under other professional current situation that does not have a data traffic.

Sub-in embodiments of the present invention scheduler module has realized that by Dual Leaky Bucket Algorithm 64 select 1 first order scheduling, and two leakage buckets are that cell leaks bucket and Token Bucket, outlet module relatively having realized by priority 16 select 1 the second level to dispatch.Specifically referring to description embodiment illustrated in fig. 4.

Fig. 4 is the internal structure and the outside block diagram that is connected of the sub-scheduler module 1 among Fig. 3.The internal structure of the sub-scheduler module of other among Fig. 3 is with sub-scheduler module 1.As shown in Figure 4, sub-scheduler module 1 comprises: inlet submodule 401, cell leaks bucket module 402, Token Bucket submodule 403, parameter submodule 404 and processing sub 405.

In Fig. 4, queue management module 301, be used for 1k bar PVC to be scheduled is divided into 16 groups, and deposit among the 1k bar PVC to be scheduled the cell number of each PVC link, and be used to finish management to the cell number of 1k bar PVC, when having individual cell to join the team as certain the current PVC in the 1st group of PVC formation, the cell number that queue management module will newly be joined the team is added on the cell number corresponding with current PVC of being stored.

Inlet submodule 401, be used for when each cell transmission cycle arrives, the cell number of 64 PVC of the 1st group in the snoop queue administration module 301, when being polled to certain current PVC, if the cell number corresponding with current poll PVC is non-zero in the queue management module 301, and the cell number corresponding with current poll PVC do not reach maximum in the cell leakage bucket module 402, and then whole values or the part value with cell number corresponding with current poll PVC in the queue management module 301 is added on the cell number corresponding to current poll PVC of preserving in the cell leakage bucket module 402.Queue management module 301 deducts corresponding value with the cell number corresponding with current poll PVC of being stored, this analog value equal above-mentioned inlet module 401 be added to cell leak preserve in the bucket module 402 corresponding to the value on the cell number of current poll PVC.

For example, the current PVC that is polled to is PVC18, the cell number corresponding with PVC18 is 5 in the queue management module 301, the cell number corresponding with PVC18 is 15 in the bucket module 402 and cell leaks, and PVC18 is 25 at the maximum cell number that cell leaks in the bucket module 402, then inlet module can be with whole cell number corresponding in the queue management module 301 with PVC 18 5 be added to cell leak in the bucket module 402 with the corresponding cell number 15 of PVC18 on, and queue management module 301 deducts corresponding value 5 with the cell number 5 corresponding with PVC18 of being stored.At this moment, the cell number corresponding with PVC18 is 15+5=20 in the cell leakage bucket module 402, and queue management module 301 is 5-5=0 with the cell number corresponding with PVC18 of being stored.

Cell leaks bucket module 402, is used for storing the cell number of every PVC of the 1st group PVC corresponding with sub-scheduler module 1.

Token Bucket submodule 403, being used for storing the 1st group PVC type of service corresponding with sub-scheduler module 1 is the token number of the PVC of variable bit rate service.

Token number in the token bucket is used to identify the professional serviced number of times of VBR on the PVC, a VBR cell on every in embodiments of the present invention transmission PVC, add 1 with this PVC corresponding token number, promptly the serviced number of times of the accumulative total of this PVC adds 1, and need spill the token of this PVC with the sustainable cell rate SCR of this PVC.This be because, the token in the token bucket that always adds up and do not leak token when operation, As time goes on when token bucket become full after, its corresponding PVC will can not get service always.When the sustainable cell rate SCR with this PVC spills the token of this PVC, its corresponding token bucket still reaches when expiring state, the transmission rate of representing the VBR cell on this PVC has reached its sustainable cell rate SCR, need this moment refusal to continue as this PVC service, become non-full state once more up to its token bucket.

The bucket that the cell corresponding with each PVC leaks bucket is high, i.e. the maximum storage value corresponding with each PVC can be taken as the CDVT value corresponding with each PVC in the cell leakage bucket module 402.To be that the PVC corresponding token of variable bit rate service is leaked the bucket of bucket high with type of service, be that the maximum storage value corresponding with each PVC can be taken as CDVT+BT in the token leakage bucket module 403, wherein BT is the value that is provided with in the TM standard 4.1 editions, and BT=(MSB-1)/(1/SCR-1/PCR).

Parameter submodule 404 is used for stores processor submodule 405 and carries out the required parameter of Dual Leaky Bucket Algorithm processing, and these parameters all have definition in TM 4.1, comprising:

1, the initial spike cell interval (INI_PCR_CI) of each PVC, the value of this parameter are the outbound port bandwidth and the ratio of the PCR of corresponding PVC, i.e. INI_PCR_CI=BAND/PCR; This parameter is represented the professional double minimum interval that obtains serving on the corresponding PVC.

2, the residue peak value cell interval (LEF_PCR_CI) of each PVC, this parameter is represented the least residue service time of corresponding PVC, this parameter represents then that greatly corresponding PVC need wait for that the time of length just can obtain service, otherwise corresponding PVC waits for that the time of weak point obtains service.In embodiments of the present invention, behind the cell of the corresponding PVC of this parameter of every transmission, this parameter INI_PCR_CI that adds up, after promptly once being served, this PVC just can be served after will waiting for the defined double minimum interval that obtains serving at least next time; And send cycle at each cell the LEF_PCR_CI of all PVC is subtracted 1 respectively, cell of promptly every mistake sends the cycle, and the residue of all PVC is also wanted corresponding minimizing service time.Therefore the maximum of LEF_PCR_CI is INI_PCR_CI, and minimum value can be configured to negative CDVT;

3, the initial average cell interval (INI_SCR_CI) of each PVC, the value of this parameter are the outbound port bandwidth and the ratio of the SCR of corresponding PVC, i.e. INI_SCR_CI=BAND/SCR; This parameter is represented the professional double statistics time interval that obtains serving on the corresponding PVC.

4, the average cell interval of the residue of each PVC (LEF_SCR_CI), this parameter are represented the statistics residue service time of corresponding PVC.In embodiments of the present invention, behind the cell of the corresponding PVC of this parameter of every transmission, this parameter INI_SCR_CI-1 that adds up, the cell of every other PVC of transmission, this parameter subtracts 1, so the maximum of LEF_SCR_CI is INI_SCR_CI, the CDVT that minimum value is configured to bear.

In embodiments of the present invention, parameter I NI_SCR_CI and LEF_SCR_CI are at the variable VBR business of bit rate, this is because the bit rate of VBR business is variable, but its peak rate can not surpass PCR, its Mean Speed can not surpass SCR, therefore utilize the peak bit rate that cell leaks bucket and INI_PCR_CI parameter and LEF_PCR_CI parameter limit VBR to be no more than PCR among the present invention, utilize the mean bitrate of Token Bucket and INI_SCR_CI parameter and LEF_SCR_CI parameter limit VBR to be no more than PCR.

Processing sub 405, be used for when each cell transmission cycle arrives, cell of poll leaks bucket module 402, content in Token Bucket submodule 403 and the parameter submodule 404, and meet the PVC of scheduling transmission condition according to the content search that is polled to, select a highest PVC of priority in the PVC the inside that meets scheduling transmission condition, and when selecting the highest PVC of service priority more than 2, select the minimum PVC of LEF_PCR_CI value, and the identification information of the PVC that will select at last sends to outlet module 303, and processing sub 405 is finished cell is leaked bucket module 402 simultaneously, the renewal of parameter in Token Bucket submodule 403 and the parameter submodule 404.

For the PVC that has disposed the CBR business, it is non-zero that its cell leaks cell number corresponding in bucket module 402, and corresponding LEF_PCR_CI is smaller or equal to 1 in the parameter submodule 404, and then this PVC scheduling of meeting processing sub 405 sends condition; For the PVC that has disposed UBR service, be non-zero as long as its cell leaks cell number corresponding in the bucket module 402, then this PVC just meets the scheduling transmission condition of processing sub 405; For the PVC that has disposed the VBR business, it is non-zero that its cell leaks cell number corresponding in the bucket module 402, the corresponding token number does not reach maximum in the Token Bucket submodule 403, and LEF_PCR_CI corresponding in the parameter submodule 404 is smaller or equal to 1, and then this PVC meets the scheduling transmission condition of processing sub 405.Wherein, if the LEF_PCR_CI corresponding with PVC smaller or equal to 1, then represent this PVC on obtaining once the service after, time-out the defined double minimum interval that obtains serving, can be served next time; If reached maximum with the professional PVC corresponding token of VBR number, the transmission rate of then representing the VBR cell on this PVC has reached its sustainable cell rate PCR, the VBR cell that continues again to send on this PVC will surpass its sustainable cell rate PCR, this moment refusal sends this PVC and goes up the VBR cell, up to its token number less than maximum.

Priority relationship between each business is followed successively by as previously described from high to low: CBR, RT-VBR, NRT-VBR, UBR.If there is the PVC of many identical services to meet the transmission condition, then processing sub 405 is selected the minimum PVC of a LEF_PCR_CI value, and sends the identification information of selected PVC to outlet module 303.That establish processing sub 405 final selections in the present embodiment is PVC 63.

After the outlet module among Fig. 4 303 selects a PVC to dispatch transmission, then feed back its selection result to each sub-scheduler module from 16 selected PVC of sub-scheduler module.

When the PVC that sends when the selected scheduling of outlet module 303 was the selected PVC 63 of the processing sub 405 of sub-scheduler module 1, processing sub 405 was leaked cell in the bucket module 402, and the cell number corresponding with the PVC that obtains serving 63 subtracts 1.Simultaneously processing sub 405 is in the parameter submodule 404, adds INI_PCR_CI-1 on the LEF_PCR_CI value corresponding with PVC 63.Do not obtain the PVC that serves for other, promptly PVC 0 to PVC 62, and processing sub 405 subtracts 1 respectively with LEF_PCR_CI value corresponding with these 63 PVC in the parameter submodule 404.If the type of service of the PVC63 that obtains serving is VBR, then processing sub 405 also needs token leaked in the bucket module 403 and adds 1 with PVC 63 corresponding token numbers.

The basis for estimation that outlet module 303 selects a PVC to dispatch transmission from 16 selected 16 PVC of sub-scheduler module can be: at first, priority according to business is judged, then for the multiple pvcs of identical services, judge that according to the LEF_PCR_CI value more little its priority of LEF_PCR_CI value is high more.

In addition, processing sub 405 also will realize regularly spilling the function of token in the Token Bucket.Under 156M dominant frequency clock, processing module 405 in the per 110 cell transmission cycles of clapping to cell leak in bucket module 402, Token Bucket submodule 403 and the parameter submodule 404 the content poll once, for LEF_SCR_CI corresponding in the parameter submodule 404 smaller or equal to 1 and Token Bucket submodule 403 in the corresponding token number be the PVC of non-zero, token leaked in the bucket module 403 subtract 1 with described PVC corresponding token number, and, subtract 1 again with the NI_SCR_CI value of the described PVC that adds up on the LEF_SCR_CI value corresponding in the parameter submodule 404 with described PVC; Greater than 1 PVC, its LEF_SCR_CI value is subtracted 1 for LEF_SCR_CI in the parameter submodule 404.

In the above embodiment of the present invention, each parameter has been carried out adding 1 or subtract 1 operation, can certainly add and subtract other numerical value to each parameter, the size of the numerical value of concrete plus-minus can preestablish according to actual business requirement.In addition, in the above-described embodiments, leak bucket for CBR and UBR service are provided with cell, cell leaks bucket and Token Bucket and be the VBR business setting.Can certainly only, the PVC of VBR business leak bucket for being provided with cell, need not to carry out this moment to Token Bucket and remain average cell interval parameter and the setting of initial average cell interval parameter and upgrade and handle, but at this moment can not guarantee the sustainable cell rate SCR of VBR business, here no longer narration.

By embodiment shown in Figure 4 as seen, when the embodiment of the invention is selected the 1st grade of scheduling of 1 with Dual Leaky Bucket Algorithm realization 64, be provided with cell leakage bucket, initial spike cell interval parameter I NI_PCR_CI and the residue peak value cell interval parameter L EF_PCR_CI that is used to store the PVC cell number for every PVC to be scheduled; And, be provided with and be used to store PVC token number purpose Token Bucket, initial average cell interval parameter I NI_SCR_CI and residue peak value cell interval parameter L EF_SCR_CI for type of service is every PVC to be dispatched of variable bit rate service.And in each cell transmission cycle, all according to the final result that sends above-mentioned parameter is upgraded accordingly, so that provide the selection foundation for the PVC in the next cell transmission cycle dispatches.Therefore, if the business of certain bar PVC does not obtain service in the current scheduling process, then system reduces its residue service time, its probability of obtaining serving in scheduling is next time increased, thereby it is compensated in the service of back.And real renewal when system keeps the state of each parameter makes that the business of the PVC that each scheduling sends all is the prepreerence business that obtains serving that needs most.

In sum, in embodiments of the present invention, by minute technical scheme of two-level scheduler PVC, guarantee high outbound port speed when having realized the scheduling multiple pvcs, thereby improved the QoS of atm network.And in the graded dispatching process, use Dual Leaky Bucket Algorithm, calculate it for the business of every PVC and remain service time, and carry out selection scheduling service time according to service priority and professional residue, thereby between PVC, realized fairness dispatch, and guaranteed that every PVC goes up professional statistics bandwidth.

The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention, all any modifications of being made within the spirit and principles in the present invention, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1, the method for a kind of dispatching permanent virtual path PVC is characterized in that, this method comprises:

2, the method for claim 1 is characterized in that, described PVC to be scheduled is divided into N group is that PVC to be scheduled is divided into the N group fifty-fifty.

3, the method for claim 1 is characterized in that,

The described step of selecting a PVC from N group PVC among each group PCV at most comprises: for each group PVC, search the PVC that meets scheduling transmission condition among this group PVC respectively, when finding, from the PVC that meets scheduling transmission condition, find the highest PVC of service priority, when the quantity of the highest PVC of service priority is 1, directly select the highest PVC of this service priority, when the quantity of the highest PVC of service priority when being a plurality of, from the highest PVC of these a plurality of service priority, select a PVC.

4, method as claimed in claim 3 is characterized in that,

This method further comprises: be described every PVC to be scheduled, be provided for storing cell leakage bucket and the initial spike cell interval parameter and the residue peak value cell interval parameter of this PVC cell number; Send the cycle at each cell, the cell number in the cell leakage bucket of the current PVC that obtains serving is deducted 1; All residue peak value cell interval parameters that do not obtain the PVC that serves are deducted predetermined value respectively; Add up on the residue peak value cell interval parameter with the current PVC that obtains the serving initial spike cell interval parameter value of the current PVC that obtains serving deducts predetermined value again;

The described PVC that meets scheduling transmission condition comprises: the corresponding service type is a constant bit rate, and the cell number that corresponding cell leaks in the bucket is a non-zero, and residue peak value cell interval parameter is smaller or equal to the PVC of predetermined value; And/or the corresponding service type is the Unspecified Bit Rate business, and the cell number that corresponding cell leaks in the bucket is the PVC of non-zero; And/or the corresponding service type is a variable bit rate service, and the cell number that corresponding cell leaks in the bucket is a non-zero, and residue peak value cell interval parameter is smaller or equal to the PVC of predetermined value.

5, method as claimed in claim 4 is characterized in that,

This method further comprises: for type of service is every PVC to be dispatched of variable bit rate service, be provided for storing token number purpose Token Bucket and initial average cell interval parameter and the average cell interval parameter of residue that this type of service is variable bit rate service PVC; Send the cycle at each cell, when the type of service of the current PVC that obtains serving is variable bit rate service, the token number in the Token Bucket of the current PVC that obtains serving is added 1; Send the cycle at each cell, to remaining the PVC of average cell interval parameter smaller or equal to predetermined value, if the token number that the average cell interval parameter of this residue is leaked in the bucket smaller or equal to the PVC corresponding token of predetermined value is a non-zero, then will remain average cell interval parameter and subtract 1 smaller or equal to the token number in the Token Bucket of the PVC of predetermined value, and this remains the initial average cell interval parameter value of average cell interval parameter smaller or equal to the PVC of predetermined value smaller or equal to adding up on the average cell interval parameter of the residue of the PVC of predetermined value will to remain average cell interval parameter, deduct predetermined value again, and, for wherein remaining the PVC of average cell interval parameter, this is remained average cell interval parameter deduct predetermined value greater than the average cell interval parameter of the residue of the PVC of predetermined value greater than predetermined value;

Comprise that when described meeting among the PVC that dispatches the transmission condition corresponding service type is a variable bit rate service, and the cell number that corresponding cell leaks in the bucket is a non-zero, and residue peak value cell interval parameter is during smaller or equal to the PVC of predetermined value, and this type of service is that variable bit rate service, the corresponding cell token number that to leak cell number in the bucket be non-zero and residue peak value cell interval parameter further satisfies in the corresponding Token Bucket smaller or equal to the PVC of predetermined value does not reach peaked condition.

6, as claim 4 or 5 described methods, it is characterized in that, the described step of selecting a PVC from all PVC that selected comprises: find the highest PVC of service priority from all PVC that selected, when the quantity of the highest PVC of the service priority that finds from described all PVC that selected is 1, the highest PVC of this service priority that direct selection finds from described all PVC that selected, when the quantity of the highest PVC of the service priority that from described all PVC that selected, finds when being a plurality of, select a PVC among the highest PVC of these a plurality of service priority that from described all PVC that selected, find.

7, method as claimed in claim 6 is characterized in that,

From N group PVC each is organized relate in the process of selecting a PVC among PCV at most described and is selected a PVC to comprise from the highest PVC of a plurality of service priority: a PVC who selects residue peak value cell interval parameter value minimum from the highest PVC of a plurality of service priority;

Selecting relate in the process of a PVC described from all PVC that selected selects a PVC to comprise from the highest PVC of a plurality of service priority: a PVC who selects residue peak value cell interval parameter value minimum from the highest PVC of a plurality of service priority.

8, a kind of device of dispatching PVC, it is characterized in that this device comprises: comprise queue management module, a N scheduler module and the outlet module of N group PVC, wherein, N is the natural number greater than 1, and it is corresponding one by one that N sub-scheduler module and N in the queue management module organize PVC;

9, device as claimed in claim 8 is characterized in that, described each sub-scheduler module includes: inlet submodule, cell leak bucket module, parameter submodule and processing sub, wherein,

Cell leaks the bucket module, is used for storing the cell number of every PVC of the PVC group corresponding with the sub-scheduler module in place;

The parameter submodule, the initial spike cell interval parameter, the residue peak value cell interval parameter that are used for storing PVC group every the PVC corresponding with the sub-scheduler module in place;

The inlet submodule is used for when each arrives in cell transmission cycle, each the bar PVC in the poll PVC group corresponding with the sub-scheduler module in place, and the cell number of each bar PVC of being polled to write in the cell leakage bucket module;

Processing sub is used for cell being leaked cell number corresponding with the current PVC that obtains serving in the bucket module subtracting 1 when each cell transmission cycle arrives; Do not subtract a predetermined value respectively with not obtaining the corresponding residue peak value cell interval parameter of the PVC that serves with all in the parameter submodule; Residue peak value cell interval parameter corresponding with the current PVC that obtains serving in the parameter submodule added up go up the initial spike cell interval parameter value of the current PVC that obtains serving, subtract predetermined value again; And when each cell transmission cycle arrives, cell of poll leaks the content of the storage in bucket module and the parameter submodule, and from the PVC group of correspondence, find out the PVC that meets scheduling transmission condition according to the content of described poll, from the PVC that meets scheduling transmission condition, find the highest PVC of service priority again, when the quantity of the highest PVC of service priority is 1, directly select the highest PVC of this service priority, when the quantity of the highest PVC of service priority when being a plurality of, select a PVC from the highest PVC of these a plurality of service priority, the identification information with the PVC that selects sends to described outlet module at last.

10, device as claimed in claim 9 is characterized in that, described each sub-scheduler module further comprises the Token Bucket submodule, and being used for storing the PVC group type of service corresponding with the sub-scheduler module in place is the token number of the PVC of variable bit rate service;

Described parameter submodule is further used for storing in the PVC group corresponding with the sub-scheduler module in place, and type of service is initial average cell interval parameter and the average cell interval parameter of residue of the PVC of variable bit rate service;

Described processing sub is further used for when each arrives in cell transmission cycle, when the type of service of the current PVC that obtains serving is variable bit rate service, token leaked in the bucket module adds 1 with the current PVC corresponding token number that obtains serving; Is the PVC of non-zero for the average cell interval parameter of residue corresponding in the parameter submodule smaller or equal to corresponding token number in predetermined value and the Token Bucket submodule, token leaked in the bucket module to remain average cell interval parameter with this be that the PVC corresponding token number of non-zero subtracts 1 smaller or equal to predetermined value and token number, and be to add up this on the corresponding average cell interval parameter of residue of the PVC of non-zero to remain average cell interval parameter be the initial average cell interval parameter value of the PVC of non-zero smaller or equal to predetermined value and token number remaining average cell interval parameter with this in the parameter submodule smaller or equal to predetermined value and token number, subtract predetermined value again; Subtract predetermined value with remaining average cell interval with this in the parameter submodule greater than the average cell interval parameter of the corresponding residue of the PVC of predetermined value greater than the PVC of predetermined value for the average cell interval of residue in the parameter submodule.