CN100417136C - Down queue fast back pressure transmitting based on three-stage exchange network - Google Patents
Down queue fast back pressure transmitting based on three-stage exchange network Download PDFInfo
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Abstract
The present invention relates to a downlink queue fast back pressure transferring device and a method based on a three-stage switching network, which comprises a queue manager groups composed of 16 uplink queue managers and 16 downlink queue managers. A third stage output module sends the downlink queue back pressure information of each downlink queue manager to each corresponding uplink queue manager; a first stage input module transfers the received downlink queue back pressure information to an intermediate stage back pressure processing module in an in-band mode; the intermediate stage back pressure processing module processes the downlink queue back pressure state information, and sends the downlink queue back pressure state information to each downlink queue manager of the third stage output module in an in-band mode; the third stage output module extracts the downlink queue back pressure state information sent from the intermediate stage back pressure processing module, and sends the downlink queue back pressure state information to the uplink queue managers corresponding to the downlink queue back pressure state information; each uplink queue manager of the first stage input module controls the cell transmission of each queue according to the received downlink queue back pressure state information. The present invention can be used for the downlink queue fast back pressure transfer of the three-stage switching network.
Description
Technical field
The invention belongs to the Data Interchange Technology field, especially a kind of down queue fast back pressure transmitting and method based on three grades of switching networks, utilize the disposable message bit pattern that carries down queue back-pressure state of payload of idle cell, the header that is used in combination cell of data carries the message bit pattern of down queue back-pressure state in batches, thereby send it to uplink module apace, improve back-pressure response speed and reliability.
Technical background
Switching network (Switch Fabric) is the core of broadband switching equipment such as switch (ATM)/router, it finishes the exchange of packet between the port or cell, promptly the packet that arrives input port or cell according to its destination interface information exchange of carrying to corresponding output port.
According to the difference of the medium of exchange, switching network can be divided into time-division switching and two kinds of structures of space switching.
In the time-division switching structure, each port is shared a communication medium in time-multiplexed mode, and these medium both can be memories, also can be bus or ring.Obviously, the bandwidth of shared medium has just determined the capacity of switching network.The exemplary of time division switching network is shared buffer memory and shared bus switching fabric, because its autgmentability is relatively poor, generally only is used in the low capacity switching equipment.
The space switching structure is to utilize line and electronic switch to finish interconnection between the port, can be divided into single-stage and multistage switched network.Typical single-stage switching network comprises cross-connect matrix (Crossbar) structure, and multistage switched network then comprises Cronous (Clos) structure, banyan (Banyan) structure etc.Because the space switching structure has favorable expansibility, thereby is applied to more in the big capacity switching equipment.
In the prior art, what more commercial switching network adopted is to mix switching fabric, and Fig. 1 promptly is three grades of switching networks of a kind of typical M-S-M (Memory-Space-Memory).
The M-S-M switching network adopts three grades of Clos structures: the first order and the third level are the shared buffer memory switching fabric, and the first order is finished buffer memory, Route Selection and the queue management to the input cell, and the third level is finished buffer memory, exchange and the queue management to the output cell; Intergrade is the space switching structure, mainly finishes the function of exchange of cell.Guarantee that by dispatching algorithm efficiently the cell that enters intergrade does not bump between the first order and the intergrade.This structure composition the advantage of shared buffer memory exchange and Crossbar space switching, make and construct high efficiency, become possibility from the large-scale switching network of route.
In the first order of switching network, in order to solve the hol blocking problem, adopt VOQ (VOQ, Virtual Output Queue) structure, promptly import cell and line up according to its destination interface.Like this, the cell of output port of competition failure can not influence this input port and obtains other idle output ports.
The third level of switching network, cell is ranked by output port.When output port take place to block when causing output queue long, the third level will notify that the VOQ corresponding to this output port stops to send cell to it in all input port formations, cause dropped cell in order to avoid third level formation is overflowed, down queue back-pressure that Here it is.
Yet the granularity of this down queue back-pressure is thick excessively, can have influence on VOQ corresponding with it in all input port formations because certain third level formation produces back-pressure.
In order to address this problem, in third level output queue, introduce virtual input queue (VIQ, VirtualInput Queue) structure, the cell output queue is further ranked according to its source input port.Like this, third level VIQ is just corresponding one by one with first order VOQ, thereby makes the granularity of down queue back-pressure reach thinner.
For a N * N switching network, support K kind priority, then have N * K VIQ in the third level output queue altogether.Have only rapidly and accurately to send the down queue back-pressure information to the first order, could guarantee not dropped cell and keep high percent of pass of entire switching network.
The down queue back-pressure adopts usually in outer transmission of band and the band and transmits dual mode.Under the transmission mode, each third level output module is passed to each first order input module by special back-pressure holding wire with the formation back-pressure information outside band.It has dual mode again:
The first, third level output module is directly drawn the back-pressure holding wire to each first order input module.If the switching port number is N, then the back-pressure holding wire adds up to N * N.
The second, each third level output module draws a back-pressure holding wire to intergrade, and the intergrade module will be distributed to each first order input module after will handling from the down queue back-pressure information of each third level output module.Therefore, if the switching port number is N, and intergrade has only a module to be responsible for handling back-pressure information, and then the back-pressure holding wire adds up to 2 * N.For the purpose of reliable, intergrade has more module usually and handles back-pressure information, module of every increase, and the back-pressure holding wire will increase by 2 * N bar.
Adopt out-band method to transmit the down queue back-pressure information, maximum problem is exactly that the back-pressure line number signal is too much.Along with increasing of number of modules, the back-pressure holding wire will be quadratic growth, and for the multiport of wiring very dense, big capacity switching network, its physics realization difficulty is very big.
Load mode in the down queue back-pressure band is about to utilize the folding correspondence of three grades of Clos switching networks in the third level back-pressure information affix cell of data head, sends it to corresponding first order input module.
As transmitting shown in the schematic diagram in Fig. 2 down queue back-pressure adopts band, suppose that the VIQn among the third level output port m is long, then need the VOQm among the back-pressure first order input port n.The transport process of formation back-pressure state is as follows: third level port m sends formation back-pressure state to corresponding first order port m, and the first order port m give intergrade with the head that it appends to output stream.The back-pressure processing module of intergrade (BPP, Back-Pressure Processor) appends to the head of the data flow that exchanges to third level port n with it after the back-pressure state is extracted and handles.After third level port n extracts the back-pressure state, give corresponding first order port n with it.After input port n receives formation back-pressure state from VIQn, suspend to port m and send cell.The releasing process of back-pressure state is like this equally.
For a N * N switching network, support K kind priority, then have N * K VIQ in the third level output queue altogether.Transmit the back-pressure state of this N * K down queue, dual mode arranged:
The first, adopt bitmap (bitmap) mode to transmit, the state of each corresponding formation in position (bit), 1 expression back-pressure, 0 represents not back-pressure.For N * K VIQ, need with N * K bit.
The second, a formation that transmission queue's back-pressure state changes comprises its queue number, back-pressure state and back-pressure state variation.
For adopting the bitmap mode to transmit down queue back-pressure state, when number of queues especially for a long time, can cause the header expense excessive, influence normal exchanges data.For example, for one 64 * 64, support the switching network of 4 kinds of priority, the third level always has 256 VIQ, if each cell cycle is all transmitted down queue back-pressure state, then needs to take 32 byte headers.Obviously, this expense is too big.In order to address this problem, the back-pressure state of down queue can be divided into several parts, each cell cycle is only transmitted a wherein part.This time delay that can cause back-pressure to transmit again increases, and controls bad meeting and causes the first order buffer memory vibration to occur.
Mode for transmitting the back-pressure state variation has following shortcoming: the first, from a lot of quene states, select the formation that 1 or several state change in the cycle at very short cell, and realize that difficulty is very big; The second, poor reliability is if the formation back-pressure state variation that is transmitted just may cause the switching network packet loss because certain accident is lost as data link error code; The 3rd, when the number of queues that state variation takes place very for a long time, the time delay that can cause back-pressure to transmit sharply increases, and causes the vibration of first order buffer memory.
Summary of the invention
For overcoming the deficiencies in the prior art, the object of the present invention is to provide a kind of down queue fast back pressure transmitting and method, to improve the speed of back-pressure response based on three grades of switching networks.
Another object of the present invention is to provide a kind of down queue fast back pressure transmitting and method based on three grades of switching networks, to improve the reliability of back-pressure response.
For finishing the foregoing invention purpose, the technical solution used in the present invention is: a kind of down queue fast back pressure transmitting based on three grades of switching networks, described three grades of switching networks comprise first order input module, intergrade back-pressure processing module and third level output module, in the first order input module VOQ is arranged, in the third level output module virtual input queue is arranged, in each cell cycle, the third level output module wherein back-pressure state information of virtual input queue sends corresponding first order input module to, the output port of first order input module is encapsulated in it in output cell and gives intergrade back-pressure processing module, the back-pressure processing module extracts the back-pressure state information and handles, back-pressure state information after treatment is encapsulated in the output cell and delivers to third level output module, third level output module extracts the back-pressure state information and gives corresponding first order input module with it, control VOQ wherein sent cell to the virtual input queue of the third level after first order input module was received formation back-pressure state information, described first order input module comprises one group of upstream queue manager, each upstream queue manager includes unicast cell set of queues and multicast cell-queue group, be used to import the down queue back-pressure information of third level output module output, and it be encapsulated in one-to-many sends intergrade back-pressure processing module in the output cell; Corresponding third level output module is handled and be distributed to described intergrade back-pressure processing module, the back-pressure state information that is used for that the upstream queue manager is sent here; Described third level output module comprises one group of down queue manager, quantity is identical with the upstream queue manager, the down queue manager includes unicast cell set of queues and multicast cell-queue group, is used for that formation back-pressure state information is delivered to the back-pressure state information of sending here after handling with its corresponding upstream queue manager with intergrade back-pressure processing module and passes to the upstream queue manager corresponding with it.
Described upstream queue manager and down queue manager number are respectively 16.
The clean culture input rank group number of described each upstream queue manager is 16.
Each unicast cell set of queues of described each upstream queue manager is divided into 4 clean culture VOQs, and each clean culture VOQ is divided into 4 subqueues according to priority, has 256 clean culture subqueues.
The multicast cell-queue group number of described each upstream queue manager is 16.
The multicast cell-queue component of described each upstream queue manager is 1 multicast virtual output queue, and each multicast virtual output queue is divided into 4 subqueues according to priority, has 64 multicast subqueues.
The unicast cell set of queues number of described each down queue manager is 4.
Each unicast cell set of queues of described each down queue manager is divided into 16 clean culture virtual input queues, and each clean culture virtual input queue is divided into 4 subqueues according to priority, has 256 clean culture subqueues.
The multicast cell-queue group number of described each down queue manager is 1.
The multicast cell-queue component of described each down queue manager is 16 multicast virtual input ranks, the corresponding upstream queue manager of each multicast virtual input rank, each multicast virtual input rank is divided into 4 subqueues according to priority, has 64 multicast subqueues.
Described each down queue manager has at least two group down queue back-pressure status signal lines to corresponding upstream queue manager, one group of holding wire is used for the down queue manager to be given intergrade back-pressure processing module with the down queue back-pressure state information of oneself by the upstream queue manager and handles, and the down queue back-pressure state information after another group holding wire is used for intergrade back-pressure processing module handled is given the upstream queue manager by the down queue manager.
A kind of down queue fast back pressure transfer approach based on three grades of switching networks may further comprise the steps:
Each upstream queue manager of corresponding first order input module delivered to the down queue back-pressure state information in each down management device formation by step 1, third level output module;
Step 3, intergrade back-pressure processing module are handled down queue back-pressure state information, and issue each down queue manager of third level output module with in-band method;
Step 4, third level output module extract the down queue back-pressure state information of sending here from intergrade back-pressure processing module, and send it to the upstream queue manager corresponding with it;
The cell that step 5, each upstream queue manager of first order input module are controlled each formation according to the down queue back-pressure state information of being received sends.
Down queue back-pressure state information length in the described step 1 is 320.
The outlet bandwidth of the upstream queue manager in the described step 1 is greater than going into port band width.
Correspondence in the described step 1 is meant that specifically m virtual input queue in the unicast queue group of n down queue manager is corresponding one by one with n unicast cell set of queues of m upstream queue manager, and m virtual input queue in the multicast set of queues of n down queue manager is corresponding one by one with n multicast cell-queue group of m upstream queue manager, and n and m are respectively natural number.
In-band method in the described step 2 is that the upstream queue manager regularly sends idle cell to intergrade back-pressure processing module, utilizes the disposable mode that the down queue back-pressure information is sent to intergrade back-pressure processing module of idle cell payload part.
Described idle cell comprises that per 4 bytes pass 20 information bits and 1 horizontal odd parity bit of the back-pressure state information of one group of virtual input queue.
In-band method in the described step 2 can also be the header load mode partly of utilizing cell of data.
The header part of described cell of data once transmits 40 down queue back-pressure state informations that comprise 8 unicast queues and 2 multicast formations.
The time that the described header that utilizes cell of data partly transmits all 320 down queue back-pressure state informations is 8 cell cycles.
The header of described cell of data partly also has a sign, and which part down queue back-pressure state information is used to discern what transmitting is.
The beneficial effect that technical solution of the present invention is brought.The present invention is provided with the upstream queue manager at three grades of switching network first order input modules, the upstream queue manager comprises 16 unicast cell set of queues and 16 multicast cell-queue groups, cell according to each formation of down queue back-pressure State Control sends, third level output module is provided with the down queue manager, it comprises 4 unicast cell set of queues and an independent multicast cell-queue group, the down queue back-pressure information can be given corresponding upstream queue manager, send intergrade back-pressure processing module by the upstream queue manager to in-band method, deliver to third level output module through the back-pressure information of after the processing of intergrade back-pressure processing module needs being given each down queue manager with in-band method, deliver to corresponding upstream queue manager after the down queue back-pressure state that the down queue manager is sent here after each intergrade back-pressure processing module is handled merges.Intergrade back-pressure processing module, the back-pressure state information that each upstream queue manager can be sent here is handled, and the down queue back-pressure information after will handling is delivered to each down queue manager with in-band method.The present invention utilizes the idle cell payload to carry down queue back-pressure state information, and a cell cycle can be finished the transmission of whole down queue back-pressure states, and speed is fast.Improved the speed that back-pressure transmits.The header that perhaps is used in combination cell of data transmits down queue back-pressure state information in batches, can guarantee still can regularly upgrade the back-pressure state in the very big situation of data traffic, has improved the reliability of switching network.
Description of drawings
Fig. 1 is three grades of switching network schematic diagrames of M-S-M of prior art;
Fig. 2 is that the down queue back-pressure of prior art adopts transmission schematic diagram in the band;
Fig. 3 is 64 * 64 3 grades of switching network schematic diagrames;
Fig. 4 is the formation corresponding relation figure of upstream queue manager and down queue manager;
Fig. 5 is the formation back-pressure frame format figure of upstream queue manager to intergrade back-pressure processing module header;
Fig. 6 is the conversion process figure of intergrade back-pressure process information module to down queue back-pressure state;
Fig. 7 is the formation back-pressure frame format figure of intergrade back-pressure processing module to down queue manager header.
Embodiment
Below in conjunction with Figure of description the specific embodiment of the present invention is described.
N * N switching network comprises 3-level module, comprise first order input module, intergrade back-pressure processing module and third level output module, in the first order input module VOQ is arranged, in the third level output module virtual input queue is arranged, in each cell cycle, the third level output module wherein back-pressure state information of virtual input queue sends corresponding first order input module to, the output port of first order input module is encapsulated in it in output cell and gives intergrade back-pressure processing module, the back-pressure processing module extracts the back-pressure state information and handles, back-pressure state information after treatment is encapsulated in the output cell and delivers to third level output module, third level output module extracts the back-pressure state information and gives corresponding first order input module with it, and control VOQ wherein sent cell to the virtual input queue of the third level after first order input module was received formation back-pressure state information.
The first order input module of three grades of switching networks of N * N of the present invention includes one group of upstream queue manager, its end connects the output port of third level output module down queue manager, the other end connects intermediate process module, each upstream queue manager includes unicast cell set of queues and multicast cell-queue group, instruction according to processor, be used to import the down queue back-pressure information of third level output module output, and it be encapsulated in one-to-many sends intergrade back-pressure processing module in the output cell.Intergrade back-pressure processing module is mainly used in the back-pressure state information that the upstream queue manager is sent here and handles and be distributed to corresponding third level output module.Third level output module includes one group of down queue manager, quantity is identical with the upstream queue manager, its end connects intermediate process module, the other end connects the input port of the upstream queue manager of first order output module, the down queue manager includes unicast cell set of queues and multicast cell-queue group, according to the instruction of processor, be used for that formation back-pressure state information is delivered to the back-pressure state information of sending here after handling with its corresponding upstream queue manager with intergrade back-pressure processing module and pass to the upstream queue manager corresponding with it.
Shown in Figure 3 is three grades of switching networks of one 64 * 64, and it supports 4 kinds of priority and multicast.The first order input module of switching network is called upstream queue manager group (iQM, ingress Queue Manager), is used to finish buffer memory and upstream queue management to the input cell; Third level output module is called down queue manager group (eQM, egress Queue Manager), finishes buffer memory and down queue management to the output cell; Intergrade back-pressure processing module is cross-connect matrix group (Crossbar), finishes cell switching, arbitration and down queue back-pressure and handles.
In iQM, unicast cell is pressed the queuing of line output port, 64 VOQs (VOQ) altogether.Each VOQ is divided into 4 subqueues according to priority again, so has 256 clean culture subqueues among the iQM.The multicast cell duplicates earlier once in iQM, enters 16 multicast formations at most, the corresponding eQM of each multicast formation.Each multicast formation is divided into 4 subqueues according to priority again, so has 64 multicast subqueues among the iQM.Lump together, 320 formations are arranged among the iQM.
In eQM, unicast cell at first according to the queuing of purpose output port, has 4 unicast queue groups.Each clean culture output queue group again with cell according to from which iQM queuing, be divided into 16 clean culture input ranks (VIQ).Each clean culture VIQ is divided into 4 subqueues according to priority again, so has 4 * 16 * 4=256 clean culture subqueue among the eQM.Simultaneously, the multicast cell advances the multicast set of queues separately, which eQM to be divided into 16 multicast VIQ according to the multicast cell again from.Each multicast VIQ is divided into 4 subqueues according to priority again, so has 16 * 4=64 multicast subqueue among the eQM.Lump together, 320 subqueues are also arranged among the eQM.
As shown in Figure 4, the subqueue among upstream queue manager iQM and the down queue manager eQM is one to one.For example, the VOQ VOQn among m iQM is corresponding with the virtual input queue VIQm of descending output port n.Therefore, as the subqueue VIQm among the output port n during, just need the VOQn among m the corresponding iQM of notice to stop to send cell by back-pressure.
The step that sends 320 formation back-pressure states of 16 eQM, each eQM altogether to corresponding iQM rapidly and accurately is as follows:
1,, the down queue back-pressure mode bit of the 320-bits among the eQM is delivered to the iQM corresponding with this eQM by holding wire in each cell cycle.
2, iQM sends the down queue back-pressure information of this 320-bits to intergrade BPP module with in-band method, and dual mode is arranged:
First kind of mode utilized the payload part of idle cell.In three grades of switching networks, in order to improve the percent of pass of intergrade Crossbar, can between I and II, adopt certain acceleration, it is big that the outlet bandwidth ratio that is to say iQM is gone into port band width.Therefore, iQM can regularly send idle cell to intergrade.Utilize the payload of idle cell, each cell cycle can send intergrade to by disposable down queue back-pressure information with 320-bits, has improved the speed that back-pressure transmits.Define idle cell form such as the table 1 of iQM to intergrade:
Table 1 upstream queue manager is to the idle cell payload format of intergrade back-pressure processing module
| Byte number | bit[31:16] | bit[15:12] | bit[11] | bit[10:0] |
| 0-3 | UQGroup[4:1]/VIQ1_Pri[3:0] | MQGroup/VIQ1_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 4-7 | UQGroup[4:1]/VIQ2_Pri[3:0] | MQGroup/VIQ2_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 8-11 | UQGroup[4:1]/VIQ3_Pri[3:0] | MQGroup/VIQ3_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 12-15 | UQGroup[4:1]/VIQ4_Pri[3:0 ] | MQGroup/VIQ4_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 16-19 | UQGroup[4:1]/VIQ5_Pri[3:0] | MQGroup/VIQ5_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 20-23 | UQGroup[4:1]/VIQ6_Pri[3:0] | MQGroup/VIQ6_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 24-27 | UQGroup[4:1]/VIQ7_Pri[3:0] | MQGroup/VIQ7_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 28-31 | UQGroup[4:1]/VIQ8_Pri[3:0] | MQGroup/VIQ8_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 32-35 | UQGroup[4:1]/VIQ9_Pri[3:0] | MQGroup/VIQ9_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 36-39 | UQGroup[4:1]/VIQ10_Pri[3:0] | MQGroup/VIQ10_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 40-43 | UQGroup[4:1]/VIQ11_Pri[3:0] | MQGroup/VIQ11_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 44-47 | UQGroup[4:1]/VIQ12_Pri[3:0] | MQGroup/VIQ12_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 48-51 | UQGroup[4:1]/VIQ13_Pri[3:0] | MQGroup/VIQ13_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 52-55 | UQGroup[4:1]/VIQ14_Pri[3:0] | MQGroup/VIQ14_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 56-59 | UQGroup[4:1]/VIQ15_Pri[3:0] | MQGroup/VIQ15_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 60-63 | UQGroup[4:1]/VIQ16_Pri[3:0] | MQGroup/VIQ16_Pri[3:0] | Horizontal odd parity bit | 0x000 |
As shown in table 1, per 4 bytes pass the back-pressure state information of one group of VIQ, are total to 20-bits, increase the horizontal odd parity bit of 1-bit simultaneously, to improve the reliability that transmits.
The second way is utilized the header part of cell of data.Because header limited length, therefore each iQM transmits the down queue back-pressure state of 40-bits for the first time to the cell of data of intergrade, comprise 8 unicast queues and 2 multicast formations, each formation has 4 priority subqueues, needs 8 cell cycles to transmit all 320-bits down queue back-pressure states altogether.
Each iQM comprises 4 output ports, and each output port links to each other with the input port of Crossbar.320-bit back-pressure state information is duplicated 4 parts to 4 output ports, by cell of data head or the output of idle cell payload.Dual mode uses simultaneously, if there is cell of data to transmit, then occupation mode two; Otherwise occupation mode one.
Down queue back-pressure frame structure as shown in Figure 5, wherein, each header carries the back-pressure state bitmap (bitmap) of 40 descending subqueues, continuous 8 cells carry whole 320-bits back-pressure state bitmap, and which part down queue back-pressure state information (0-7) identifies what transmitting by back-pressure synchronous time mark (BPSYNC) is.
3, after intergrade BPP module is received the down queue back-pressure state information of all eQM that send here from iQM, be distributed to corresponding iQM after handling.Referring to Fig. 3, give third level output module from the intergrade module, wherein: the formation back-pressure state information to iQM1 is exported from the port one of intergrade module ..., port one 6 outputs to the formation back-pressure state that arrives iQM16 from the intergrade module.4 input ports of third level output module can be received the formation back-pressure state information from 4 BPP.Owing to the 320-bit formation back-pressure state information that 4 BPP send here is identical, therefore it need be got " or ", because third level output module and first order input module are a chip physically, so this 320-bit formation back-pressure state information is passed to iQM by internal signal wire.
See also Fig. 6, the conversion process of down queue back-pressure state is as follows: the back-pressure information of passing to iQM1 comprise eQM1, eQM2 ..., the formation back-pressure state information of all VIQ1 among the eQM16; The back-pressure information of passing to iQM2 comprise eQM1, eQM2 ..., the formation back-pressure state information of all VIQ2 among the eQM16; ...; The back-pressure information of passing to iQM16 comprise eQM1, eQM2 ..., the formation back-pressure state information of all VIQ16 among the eQM16.Like this, the eQM formation back-pressure information of passing to each iQM also is 320-bits just.
4, deliver to the eQM corresponding earlier with in-band method equally through the 320-bits down queue back-pressure information that needs to give each iQM after the intergrade BPP resume module, dual mode still arranged with iQM:
First kind of mode utilized the payload part of idle cell, and each cell cycle, disposable down queue back-pressure information with 320-bits was delivered to eQM.Define idle cell form such as the table 2 of intergrade to eQM:
Table 2 intergrade back-pressure processing module is to the idle cell payload format of down queue manager
| Byte number | bit[31:16] | bit[15:12] | bit[11] | bit[10:0] |
| 0-3 | VOQ[4:1]_Pri[3:0] | MQ1_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 4-7 | VOQ[8:5]_Pri[3:0] | MQ2_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 8-11 | VOQ[12:9]_Pri[3:0] | MQ3_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 12-15 | VOQ[16:13]_Pri[3:0] | MQ4_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 16-19 | VOQ[20:17]_Pri[3:0] | MQ5_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 20-23 | VOQ[24:21]_Pri[3:0] | MQ6_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 24-27 | VOQ[28:25]_Pri[3:0] | MQ7_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 28-31 | VOQ[3229]_Pri[3:0] | MQ8_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 32-35 | VOQ[36:33]_Pri[3:0] | MQ9_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 36-39 | VOQ[40:37]_Pri[3:0] | MQ10_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 40-43 | VOQ[44:41]_Pri[3:0] | MQ11_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 44-47 | VOQ[48:45]_Pri[3:0] | MQ12_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 48-51 | VOQ[52:49]_Pri[3:0] | MQ13_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 52-55 | VOQ[56:53]_Pri[3:0] | MQ14_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 56-59 | VOQ[60:57]_Pri[3:0] | MQ15_Pri[3:0] | Horizontal odd parity bit | 0x000 |
| 60-63 | VOQ[64:61]_Pri[3:0] | MQ16_Pri[3:0] | Horizontal odd parity bit | 0x000 |
As implied above, per 4 bytes pass the back-pressure state information of a set of queues, are total to 20-bits, increase the horizontal odd parity bit of 1-bit simultaneously, to improve the reliability that transmits.
The second way is utilized the header part of cell of data.Each intergrade transmits the down queue back-pressure state of 40-bits for the first time to the cell of data of eQM, comprise 8 unicast queues and 2 multicast formations (each formation has 4 priority subqueues), need 8 cell cycles to transmit all 320-bits down queue back-pressure states altogether.
Each Crossbar comprises 16 output ports, and each output port links to each other with the input port of 1 eQM, and 320-bit down queue back-pressure state information after treatment is by cell of data head or the output of idle cell payload.Therefore 4 Crossbar can send 4 input ports of 4 parts of 320-bit back-pressure state informations to eQM.
Formation back-pressure frame structure as shown in Figure 7, wherein, each header carries the back-pressure state bitmap of 40 subqueues, and continuous 8 cells carry whole 320-bits back-pressure state bitmap, and which part down queue back-pressure state information identifies what transmitting by BPSYNC (0-7) is.
5, after eQM receives the down queue back-pressure state information of the 320-bits that sends here from intergrade BPP, it is passed to corresponding iQM with it, the cell that iQM just can control each formation after according to the down queue back-pressure state of being received sends, stop to be sent cell by the formation of back-pressure, or continue not sent cell by the formation of back-pressure to descending to descending.
Need to prove that eQM has two groups of down queue back-pressure status signal lines to iQM: one group is that eQM gives intergrade BPP with the down queue back-pressure state information of oneself by iQM and handles; Another group then is that the down queue back-pressure state information after intergrade BPP will handle is given iQM by eQM.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within the claim scope of the present invention.
Claims (21)
1. down queue fast back pressure transmitting based on three grades of switching networks, described three grades of switching networks comprise first order input module, intergrade back-pressure processing module and third level output module, in the first order input module VOQ is arranged, in the third level output module virtual input queue is arranged, in each cell cycle, the third level output module wherein back-pressure state information of virtual input queue sends corresponding first order input module to, the output port of first order input module is encapsulated in it in output cell and gives intergrade back-pressure processing module, the back-pressure processing module extracts the back-pressure state information and handles, back-pressure state information after treatment is encapsulated in the output cell and delivers to third level output module, third level output module extracts the back-pressure state information and gives corresponding first order input module with it, control VOQ wherein sent cell to the virtual input queue of third level output module after first order input module was received formation back-pressure state information, it is characterized in that
Described first order input module comprises one group of upstream queue manager, each upstream queue manager includes unicast cell set of queues and multicast cell-queue group, be used to import the down queue back-pressure information of third level output module output, and it be encapsulated in one-to-many sends intergrade back-pressure processing module in the output cell;
Corresponding third level output module is handled and be distributed to described intergrade back-pressure processing module, the back-pressure state information that is used for that the upstream queue manager is sent here;
Described third level output module comprises one group of down queue manager, quantity is identical with the upstream queue manager, the down queue manager includes unicast cell set of queues and multicast cell-queue group, is used for that formation back-pressure state information is delivered to the back-pressure state information of sending here after handling with its corresponding upstream queue manager with intergrade back-pressure processing module and passes to the upstream queue manager corresponding with it.
2. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1 is characterized in that, described upstream queue manager and down queue manager number are respectively 16.
3. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1 is characterized in that, the unicast cell set of queues number of described each upstream queue manager is 16.
4. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1, it is characterized in that: each unicast cell set of queues of described each upstream queue manager is divided into 4 clean culture VOQs, each clean culture VOQ is divided into 4 subqueues according to priority, has 256 clean culture subqueues.
5. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1 is characterized in that, the multicast cell-queue group number of described each upstream queue manager is 16.
6. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1, it is characterized in that: the multicast cell-queue component of described each upstream queue manager is 1 multicast virtual output queue, each multicast virtual output queue is divided into 4 subqueues according to priority, has 64 multicast subqueues.
7. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1 is characterized in that, the unicast cell set of queues number of described each down queue manager is 4.
8. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1, it is characterized in that: each unicast cell set of queues of described each down queue manager is divided into 16 clean culture virtual input queues, each clean culture virtual input queue is divided into 4 subqueues according to priority, has 256 clean culture subqueues.
9. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1 is characterized in that, the multicast cell-queue group number of described each down queue manager is 1.
10. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1, it is characterized in that: the multicast cell-queue component of described each down queue manager is 16 multicast virtual input ranks, the corresponding upstream queue manager of each multicast virtual input rank, each multicast virtual input rank is divided into 4 subqueues according to priority, has 64 multicast subqueues.
11. the down queue fast back pressure transmitting based on three grades of switching networks according to claim 1, it is characterized in that: described each down queue manager has at least two group down queue back-pressure status signal lines to corresponding upstream queue manager, one group of holding wire is used for the down queue manager to be given intergrade back-pressure processing module with the down queue back-pressure state information of oneself by the upstream queue manager and handles, and the down queue back-pressure state information after another group holding wire is used for intergrade back-pressure processing module handled is given the upstream queue manager by the down queue manager.
12. the down queue fast back pressure transfer approach based on three grades of switching networks is characterized in that this method may further comprise the steps:
Each upstream queue manager of corresponding first order input module delivered to the down queue back-pressure state information in each down management device formation by step 1, third level output module;
Step 2, first order input module send the down queue back-pressure information that receives to intergrade back-pressure processing module with in-band method;
Step 3, intergrade back-pressure processing module are handled down queue back-pressure state information, and issue each down queue manager of third level output module with in-band method;
Step 4, third level output module extract the down queue back-pressure state information of sending here from intergrade back-pressure processing module, and send it to the upstream queue manager corresponding with it;
The cell that step 5, each upstream queue manager of first order input module are controlled each formation according to the down queue back-pressure state information of being received sends.
13. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 12 is characterized in that: the down queue back-pressure state information length in the described step 1 is 320.
14. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 12 is characterized in that: the outlet bandwidth of the upstream queue manager in the described step 1 is greater than going into port band width.
15. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 12, it is characterized in that: the correspondence in the described step 1 is meant that specifically m virtual input queue in the unicast queue group of n down queue manager is corresponding one by one with n unicast cell set of queues of m upstream queue manager, and m virtual input queue in the multicast set of queues of n down queue manager is corresponding one by one with n multicast cell-queue group of m upstream queue manager, and n and m are respectively natural number.
16. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 12, it is characterized in that: the in-band method in the described step 2 is that the upstream queue manager regularly sends idle cell to intergrade back-pressure processing module, utilizes the disposable mode that the down queue back-pressure information is sent to intergrade back-pressure processing module of idle cell payload part.
17. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 16 is characterized in that: described idle cell comprises that per 4 bytes pass 20 information bits and 1 horizontal odd parity bit of the back-pressure state information of one group of virtual input queue.
18. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 12 is characterized in that: the in-band method in the described step 2 is a load mode of utilizing the header part of cell of data.
19. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 18 is characterized in that: the header part of described cell of data once transmits 40 down queue back-pressure state informations that comprise 8 unicast queues and 2 multicast formations.
20. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 19 is characterized in that: the time that the described header that utilizes cell of data partly transmits all 320 down queue back-pressure state informations is 8 cell cycles.
21. the down queue fast back pressure transfer approach based on three grades of switching networks according to claim 20, it is characterized in that: the header of described cell of data partly also has a sign, and which part down queue back-pressure state information is used to discern what transmitting is.
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| CN100550853C (en) * | 2007-01-25 | 2009-10-14 | 华为技术有限公司 | A kind of Flow Control implementation method and device based on output queue |
| CN100591047C (en) * | 2007-02-10 | 2010-02-17 | 华为技术有限公司 | Pressure-reversion method, system and switching node of multi-level switching network |
| CN101656893B (en) * | 2009-08-04 | 2012-02-01 | 华为技术有限公司 | Multi-stage switching network |
| CN102835081B (en) * | 2012-05-21 | 2015-07-08 | 华为技术有限公司 | Scheduling method, device and system based on three-level interaction and interchange network |
| CN102780611A (en) * | 2012-06-06 | 2012-11-14 | 华为技术有限公司 | Packet switching circuit and packet switching method |
| WO2015070393A1 (en) * | 2013-11-13 | 2015-05-21 | Qualcomm Incorporated | Method and apparatus for qcn-like cross-chip function in multi-stage ethernet switching |
| CN104092632B (en) * | 2014-07-14 | 2017-11-14 | 新华三技术有限公司 | A kind of network equipment |
| CN104486237B (en) * | 2014-12-18 | 2017-10-27 | 西安电子科技大学 | Without out-of-order packet route and dispatching method in clos networks |
| CN111431811A (en) * | 2019-01-10 | 2020-07-17 | 华为技术有限公司 | Message transmission control method, device and network equipment |
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