CN1331531A - ATM token-ring network - Google Patents

Abstract

An ATM tokon-ring network suitable for building up broadband integrated service access network, especially the broadband and narrowband integrated service access platform, features that a special cell sheduling algorithm is used to meet the requirement of circuit simulation services and data service to QoS and to share the bandwidth resource by all nodes in ring dynamically and equally.

Description

ATM token-ring network

The present invention relates to the broadband access platform technology, especially a kind of being suitable in real time/non-real-time service mixes the ATM token-ring network that inserts.

In traditional narrow band access platform, generally use SDH ring or SPDH (accurate SDH) ring to connect OLT and each ONU, form the physics ring topology, as shown in Figure 1.But be connected by predefined link (as one or more E1) between OLT and each ONU, logically form Star topology, as shown in Figure 2.By the special-purpose swap data that is connected, do not share between the bandwidth resources of each connection between OLT and each ONU.Because this structure can't realize that sharing of bandwidth resources promptly can't realize statistic multiplexing, therefore also just be not suitable for access platform as sudden very strong non-real-time service.

Token technology is used comparatively extensive in data communication field, as token ring, token bus etc.By token technology, can avoid certain or some communication nodes to take Internet resources for a long time, solved each communication node at the fairness problem that occupies on the Internet resources.But these technology (token ring and token bus) are that data-oriented is communicated by letter on the one hand, can't satisfy the requirement of real time business to real-time, these technology belong to local area network technology simultaneously, can't satisfy covering and manage the requirement of scope significantly, be not suitable as to require to cover and manage scope broad band Integrated service access platform significantly.

Atm technology is a kind of connection-oriented technology.Before setting up the ATM connection, need to make up a Mathematical Modeling and accurately describe professional feature.But in fact,, be difficult to describe its traffic characteristic with a Mathematical Modeling because the variation of individual data service traffics is random processes of a non-stationary more accurately.So on the access aspect, not too be suitable for the demand that sudden very strong data service is communicated by letter towards connecting atm technology.Especially in looped network, because the incorrect meeting that business model is selected for use causes following two problems, the one, the waste of bandwidth resources, the 2nd, the unjustness that Internet resources distribute between the upstream and downstream node based on ATM.So simple atm technology also is not suitable for as the integrated service access platform.

The characteristics separately that the objective of the invention is to comprehensive narrow band access platform looped network technology, token technology and atm technology, under the different business pattern that takes into full account traditional narrow business (circuit simulation) and data service and their prerequisites to the different requirements of QOS (service quality), learn from other's strong points to offset one's weaknesses, make up the access platform that is suitable for broad band Integrated service.On the access platform of this integrated service, the good support to the traditional narrow real time business (enjoying the service quality that is equal to special line) both can be provided, also can farthest satisfy the highly paroxysmal requirement of data service simultaneously.

Above-mentioned purpose of the present invention is by introduce the token cell in the ATM looped network, by the token cell realize the looped network bandwidth resources on the looped network between each communication node in real time, dynamically, share coequally, cooperate simultaneously to send dispatching algorithm with the cell that data service designs different requirement of QOS (service quality) at traditional narrow business (circuit simulation), when guaranteeing traditional narrow business (circuit simulation) service quality, the feature that farthest catered to the height random of data communication, highly happens suddenly.

Superiority of the present invention is taking into full account traditional narrow business (circuit simulation) and data communication in business model separately and they are to the greatest differences in QOS (service quality) requirement, by in the ATM looped network, introducing token technology, made up a token bus network based on atm technology, cooperate certain cell to send dispatching algorithm simultaneously, when guaranteeing that traditional narrow business (circuit simulation) is enjoyed the service quality (low time delay and low delay variation) that is equal to private line access, make that the bandwidth resources (removing the part that narrow band service takies) of looped network are real-time between each communication node on the ring, dynamically, share coequally, farthest catered to the data service height random, the traffic performance of burst, thereby obtained maximum statistical gain, guaranteed that the utilance of looped network always keeps the highest.

In order to solve the reliability and security problem of single loop network, the ATM token-ring network is supported two-way dicyclo networking mode.

These and other purpose, advantage and feature of the present invention will be in conjunction with the drawings to the description of embodiments of the invention and further specified.In these accompanying drawings:

Fig. 1 is by SDH or PSDH link, OLT and ONU looping network topological diagram;

Fig. 2 is by predefined dedicated link, and OLT and ONU have constituted Star topology figure;

Fig. 3 is in the ATM token-ring network, is connected by predefined between ONU and the OLT, constitutes logic star network figure;

There are three ATM cell buffer queues in Fig. 4 in ONU;

Fig. 5 is the testing process figure of token cell;

Fig. 6 utilizes logical operation to detect the flow chart of token cell;

Fig. 7 utilizes comparison method to detect the flow chart of token cell;

Fig. 8 is that token is transmitted and cell transmission dispatching algorithm realization block diagram;

Figure 9 shows that generation, the management of token cell among the OLT.

Figure 10 shows that OLT and ONU form the situation of two-way double loop network.

Figure 11 shows that when certain section communication link breaks down the self-healed protection situation of looped network.

Figure 12 shows that the self-healed protection situation when certain node device generation partial fault.

The present invention combines looped network technology, token technology and atm technology, has proposed a kind of being suitable in real time/non-real-time service and has mixed the ATM token-ring network technology that inserts.

The physical topological structure of ATM token-ring network in the present invention, is connected by predefined atm link between OLT and each ONU as shown in Figure 1, forms the logic Star topology, as shown in Figure 3.Being connected between OLT and the ONU both can be that VP (Virtual Channel) connects, and also can be that VC (virtual channel) connects.

In the present invention, the basic function of OLT is that the outer cell of ring is imported in the ring, and cell is derived outside the ring in will encircling simultaneously, also is responsible for the management and the configuration of whole looped network simultaneously.

ATM switch or the miscellaneous equipment of OLT outside encircling receives ATM cell, with do not belong to the OLT node and belong to ATM cell forwarding in ring that ring is gone up each ONU node.Generally speaking, before transmitting, OLT need carry out the VPI/VCI translation.

OLT receives cell in encircling, the ATM cell that does not belong to the OLT node is transmitted to ring outer ATM switch or miscellaneous equipment.Generally speaking, before transmitting, OLT need carry out the VPI/VCI translation.This translation process is the inverse process of top translation process.

Simultaneously, OLT also is responsible for generation, the management of token cell and safeguards.In the present invention, the unjustness of upstream and downstream node on allocated bandwidth in the looped network introduced the token cell, and the token cell is that VPI/VCI or GFC are the cell of particular value.At the looped network initial phase, OLT is responsible for generating the token cell and is inserted in the looped network, and starts a timer.Under normal circumstances, in the time that can expect (timer is not overtime), OLT will detect a token cell, and generate a token cell once more and be inserted in the token-ring network, and timer simultaneously resets.If timer expiry does not detect the token cell yet, think that then the token cell loses in ring, generate a token cell once more and be inserted in the looped network, timer simultaneously resets.In order to prevent owing to reasons such as equipment fault and bit error code have unexpectedly generated the token cell in looped network, in looped network, there are two or more token cells simultaneously and cause, OLT also needs to carry out the operation of token cell deletion, promptly in a period of time, even when OLT detects the token cell, in ring, do not insert the token cell yet, so just can avoid in ring, having a plurality of token cells simultaneously.The token deletion action can have three kinds of triggering modes, and a kind of is periodically to trigger, and another is to trigger according to the specific warning information that receives from ONU, and the third is to trigger artificially by the turnkey console order.After carrying out the token deletion action, OLT will be responsible for generating and insert the token cell in looped network.

In the present invention, in order to improve the efficient of token-ring network when the underloading, the average latency when being reduced in the looped network heavy duty simultaneously, introduced the maximum length indication information element.The binary-coded information of the non-real-time service cell maximum number that is produced by this node that has comprised in the payload field of maximum length indication information element that the ONU node allows to send during once holding the token cell is the Max_Length value.For example, the length of binary-coded information can be 16bit, and then Max_Length has 9 kinds of values possibilities, and its corresponding binary-coded information sees Table 1.In fact back 8bit information is the copy of preceding 8bit information.Can provide redundancy protecting to binary-coded information in this way.

In the present invention, OLT is according to the load condition of network, by the maximum length indication information element to each ONU node be distributed on hold token during, the non-real-time service cell maximum number information that produces by this node that allows to send.When network load is light, use bigger Max_Length value, to improve network efficiency, when network load is heavier, use less Max_Length value, to reduce the average latency.

In the present invention, there is the Max_Length value of an implicit acquiescence in system, promptly after the ONU powerup/reset and before not receiving the maximum length indication information element, and the Max_Length value that system is given tacit consent to.

In the present invention, the basic function of ONU is to receive ATM cell from upstream node, hold back the ATM cell that belongs to this node, simultaneously insert real time business cell, the non-real-time service cell that produces by this node according to certain algorithm and transmit from upstream node receive but do not belong to the ATM cell of this node.

In ONU, three ATM cell buffer queues that exist nature to form, as shown in Figure 4.Cell scheduling algorithm in ONU inside is as follows:

1) preferentially send the real time business cell, under any circumstance promptly, as long as have cell etc. to be sent in the real time business formation, the then next ATM cell cycle is just seized by real time business cell-queue, be sky up to the real time business formation;

2) be under the prerequisite of sky in real time business cell-queue, the preferential ATM cell that sends in the forwarding queue, promptly as long as real time business cell-queue has cell etc. to be sent in sky and the forwarding queue, the then next ATM cell cycle just is forwarded formation and seizes, and be sky up to forwarding queue;

3) under real time business formation and forwarding queue all are empty prerequisite, and this ONU node holds the token cell, and this ONU node can send Max_Length the non-real-time service cell by this section dot generation at most so,

The ONU node participates in the maintenance to the token cell.Receive the token cell of being transmitted by upstream node if work as an ONU node, and this moment, non-real-time service cell-queue was empty, this ONU node generates a token cell immediately and sends to downstream node so.If there is cell etc. to be sent in the non-real-time service formation, this ONU node will temporarily be held the token cell so, promptly temporarily not send the token cell to downstream node.Only under following two kinds of situations, current ONU node just generates and sends to downstream node the token cell.

1) the non-real-time service formation is empty, promptly the whole transmissions of the cell in the non-real-time service cell-queue are finished (during holding the token cell, the non-real-time service cell credit of transmission is no more than Max_Lengt:

2) the non-real-time service formation is a non-NULL but this ONU node has sent Max_Length non-real-time service cell during holding the token cell;

If the ONU node during holding the token cell, receives a token cell again, illustrate then on looped network, to have two or more cells that ONU need report this incident to OLT, so that OLT initiates the operating process of deletion token cell.

In the present invention,, in time detect and send to downstream node the token cell, detection, generation and the transmission of token cell are adopted hardware and do not adopted the method for software to realize in order to guarantee the efficient of token-ring network.In express network, it is worthless adopting the method for software analysis.Because receiving, analyze and send the time of a token cell with software is Millisecond at least, for STM-1,1 millisecond just means 367 cells, for STM-4,1 millisecond just means 1467 cells, so must finish and can not adopt the method realization of software analysis with hardware.Provide the hardware implementation method that detects the token cell and send the token cell below.

As shown in Figure 5, on the UTOPIA interface between physical chip and the ATM layer chip, utilize clock signal and SOC (Start of Cell) signal, VPI/VCI in the header and GFC field are latched, arrive (by the SOC sign) and make it to refresh up to next cell.

Whether the cell that has two kinds of diverse ways to detect current reception is the token cell, and a kind of is the logical operation method, and another kind is a comparison method.

In comparison method, by Microprocessor Interface, in advance the vpi/vci value of token cell or GFC value are placed in the register of one 24 hyte or 4 hytes, will receive the VPI/CVI value of cell or the value in GFC value and the register then and compare.If equate, illustrate that the current cell that is receiving is the token cell, with the set of token cell indicating bit.Behind current cell end cycle, token cell indicating bit will return to state " 0 ", and when next token cell arrived, token cell indicating bit just became " 1 " again.If both are unequal, illustrate that then the current cell that is receiving is not the token cell.

In the logical operation method, at first with in the register each with the VPI/VCI field of token cell or GFC field in be " 0 " corresponding position negate after, carry out the logical operation again.If the result of AND-operation is " 1 ", illustrate that then the current cell that receives just again is the token cell, with the set of token cell indicating bit.Behind current cell end cycle, token cell indicating bit just returns to state " 0 ".If the result of AND-operation is not " 1 ".Illustrate that then the current cell that is receiving is not the token cell, keep the state constant (state " 0 ") of token cell indicating bit.

For example when the token cell vpi/vci value equal 0X04/0X1234, detect the logical operation of token cell and can use formula (1) to represent. $\stackrel{-}{y}=x^{24}+x^{23}+x^{22}+x^{21}+x^{20}+\stackrel{}{\stackrel{-}{x^{19}}}+x^{18}+x^{17}+$ $x^{16}+x^{15}+x^{14}+\stackrel{-}{x^{13}}+x^{12}+x^{11}+\stackrel{-}{x^{10}}+x^9+---\left(1\right)$ $x^8+x^7+\stackrel{-}{x^6}+\stackrel{-}{x^5}+x^4+\stackrel{-}{x^3}+x^2+x$

Wherein, y ecbatic, i.e. token cell indicating bit among Fig. 5.If y=" 1 " shows that then current cell is the token cell, if y=" 0 " shows that then current cell is not the token cell.x ²⁴The highest significant position (being MMB) of expression vpi field, x ¹⁷The least significant bit (LMB) of then representing vpi field.Equally, x ¹⁶Represent the highest significant position and the least significant bit of vci field respectively with x."+" then represents inclusive-OR operation.

If the vpi/vci value of token cell is for other value, as long as top formula is done corresponding change.

If in the system of a reality, only use part of V PI/VCI field, need only in the formula (1) so and remove corresponding position, and in comparison method, as long as invalid bit is not participated in relatively.

The detection algorithm of token cell can be referring to Fig. 5, Fig. 6 and Fig. 7.

In the present invention, detect the token cell after, promptly when token cell indicating bit becomes state " 1 " by state " 0 ",, then generate immediately and also send a token cell to downstream node if non-real-time service formation this moment be empty.If the non-real-time service formation is not empty, wait for that then chance sends the non-real-time service cell, non-real-time service cell numeration (passing through transmitting counter) to sending simultaneously, in case the non-real-time service formation is empty, or reached Max_Length holding the non-real-time service cell that sends during the token cell, then generate also immediately and send a token cell to downstream node, the transmitting counter that resets is simultaneously prepared for send the non-real-time service cell next time.

Fig. 8 has provided the implementation method of token generation and cell transmission dispatching algorithm.

In the present invention, token cell maker is undertaken two functions, one is that the generation of being responsible for the token cell (in fact only generates the header of 5 bytes, and payload field can be filled with any content), another is to be responsible for generating appropriate handshake, promptly when needs send the token cell to downstream node, will send request/CLAV and be changed to useful signal (when/CLAV was " 1 ", expression had cell to send).Arbitrated logic will be changed to effectively (when/ENB is " 0 ") with answer signal/ENB corresponding with it at 1 cell in the cycle, allow it to send the token cell.When CLAV and/ENB is simultaneously effectively when (be CLAV=" 1 " ,/ENB=" 0 "), and when SOC is " 1 ", begins to export first byte of header, sends subsequent byte then in proper order.Finish up to the transmission of token cell.In the token cell sent several clock cycle before finishing, token cell maker general/CLAV was changed to disarmed state (promptly/CLAV=" 0 "), avoids sending two or more token cells.

In the present invention, the major function of arbitrated logic is to have in the high priority transmit queue when sending request (during/CLAV=" 1 "), and the transmission request of the transmit queue of low priority is shielded.The function of logic arbitration can be with following algorithmic notation:

if(/CLAV－1＝1){CLAV－1＝1；CLAV－2＝CALV－3＝CLAV－4＝0；}if(/CLAV－1＝0 & /CLAV－2＝1){CLAV－2＝1；CLAV－1＝CLAV－3＝CLAV－4＝0；}if(/CLAV－1＝0 & /CLAV－2＝0 & /CLAV－3＝1){CLAV－3＝1；CLAV－1＝CALV－2＝CLAV－4＝0；}if(/CLAV－1＝0 & /CLAV－2＝0 & /CLAV－3＝0 & /CLAV－4＝1){CLAV－4＝1；CLAV－1＝CALV－2＝CLAV－3＝0；}other{CLAV－1＝CALV－2＝CLAV－3＝CLAV－4＝0；}

Annotate, " 1 " expression has cell to send, and " 0 " expression does not have cell to send out./ CLAV-1 ,/CLAV-2 ,/CLAV-3 ,/CLAV-4 is corresponding with CLAV-1, CLAV-2, CLAV-3, CLAV-4 respectively.

Correspondingly, when CLAV-1 is effective, and when/ENB-1 is effective (when/ENB-1=" 0 "), put ENB-1 effectively (being ENB-1=" 0 "), when CLAV-2 is effective, and when/ENB-2 is effective (when/ENB-2=" 0 "), put ENB-2 effectively (being ENB-2=" 0 "), when CLAV-3 is effective, and when/ENB-3 is effective (when/ENB-3=" 0 "), put ENB-3 effectively (being ENB-3=" 0 "), when CLAV-4 is effective, and when/ENB-4 is effective (when/ENB-4=" 0 "), put ENB-4 effectively (being ENB-4=" 0 ").Represent with a formula to be exactly:

ENB－X＝(！CLAV－X)OR/ENB－X，X＝1、2、3、4；

ENB－Y＝“1”，Y≠X；

Token cell indicating bit signal is by two effects, and one with the token cell indicating bit transmitting counter (logic high " 1 " is effective) that resets, and can guarantee that like this transmitting counter is always 0 when detecting each new token cell.The another one effect is when/CLAV-4 invalidating signal (/CLAV-4=" 0 ", represent current do not have the non-real-time service cell to send), starts the token cell process that sends to downstream node.

Transmitting counter utilize signal ENB-4 ,/CLAY-4 and SOC come the non real-time cell that sends is counted.When transmitting counter overflows, utilize the counter spill over to start the process that sends the token cell to downstream node.The thresholding that overflows of transmitting counter is provided with by Microprocessor Interface, and thresholding depends on current Max_Length.

Fig. 9 has provided in the present invention, the realization block diagram that OLT token cell generates, manages and safeguard.

Before system initialization, there is not the token cell in the ring, therefore, by system's control line, generate and insert a token cell at OLT.No matter under which kind of situation, when OLT sends a token cell to downstream node, all utilize SOC and/CLAV-1 signal enabling timer.

When OLT detects the token cell, token cell indicating bit will become effective status by disarmed state, promptly become state " 1 " by state " 0 ", utilize this transition process, trigger the process that sends the token cell to downstream node.At this moment, timer will be restarted, and has avoided timer expiry.If in official hour, OLT fails to detect the token cell, will cause timer expiry, this means that the token cell loses in looped network.Utilize timer expiry information, trigger the process that sends the token cell to downstream node, guarantee to have in the looped network token cell to exist.In order to prevent in token-ring network, there are two or more token cells simultaneously, by system's control line, in a period of time, forbid sending to downstream node the token cell, be about to the shielding of timer expiry indicating bit and token cell indicating bit.And then, force in looped network, to send a token cell by another root system system control line.Above mechanism can guarantee in looped network, to have and have only a token cell.

The function of the arbitration logic unit among Fig. 9 and the functional similarity of the arbitration logic unit among Fig. 8 repeat no more here.

In some nonessential application, by single fiber monocycle token network that above-mentioned skill element constituted and be enough to application, but in some critical application such as communication network, because low this congenital intrinsic defective of reliability of single loop network causes this technology can't use in these are used.In order to improve reliability, can adopt two-way double loop network as shown in figure 10.

As shown in figure 10, in each ONU, need two interface boards.OLT and ONT couple together by two-way double loop network.Outer shroud is a clockwise direction, and interior ring is counterclockwise.Under normal circumstances, have only a ring in running order, another ring is in stand-by state.In Figure 10, data flow is advanced along the indicated path of solid line.Dotted line is represented standby data channel.UTOPIA interface swap data by standard between two interface boards.

As shown in figure 11, when certain section communication link broke down, OLT and ONU equipment detected this incident, triggered the self-healed protection process, and its result is exactly two closed circuits that form again as shown in figure 10.

This only be that the business of each ONU node is all unaffected under the situation of link failure.

The contingent situation of another one is certain node break down (as outage, a fire etc.).In this situation, still can guarantee the professional unaffected of other ONU node by self-healed protection.

The contingent situation of another one is that an interface board in certain ONU node breaks down, and at this moment, inner and outer ring also all can't be worked.Also can guarantee that professional (comprising malfunctioning node) is unaffected in this case by self-healed protection.

The present invention possesses more following characteristics:

1. traditional narrow band service (circuit simulation) is provided the service quality of special-purpose connection;

A symmetry that essential characteristic is a two-way link of traditional narrow band service (referring to the E1/E3 circuit emulation service here), i.e. calling speed and outgoing speed are strict to be equated.This means that in looped network the real time business speed that the ONU node is downloaded equates with the real time business speed of insertion.So before not inserting the non-real-time service cell that the ONU node produced, the service rate of looped network only can reduce and can not increase.The insertion of narrow band service cell is before cell is transmitted on the ring, and the insertion of data service cell is after cell is transmitted on ring, so in looped network, as long as in a single day cell enters in the ring, cell just can not lost.And the narrow band service cell always preferentially inserts in the looped network in real time, and is not lost in looped network.

2. the bandwidth resources of looped network are dynamic between the non-real-time service of each ONU, real-time, fair shares;

The bandwidth resources of looped network except the part that real time business takies, other remaining bandwidth resources between each ONU unit in real time, dynamically, share liberally.When other ONU node did not have the non-real-time service cell to send, the node that send the non-real-time service cell can take all remaining bandwidth resources.When existing two or more ONU unit will send the non-real-time service cell, bandwidth resources are shared liberally by these ONU nodes, with the location independent of node.This is because used token technology in looped network, has solved fairness problem.

3. be suitable for the access that mixes of real time business and non-real-time service;

Characteristics 1 have illustrated that the ATM token-ring network can insert real time business, and to be used for the very strong data service of access burst be non-real-time service and characteristics 2 explanation ATM token-ring networks are suitable.

4. efficient height, the superior performance of looped network;

In the ATM token-ring network, adopt hardware to finish detection, the transmission of token cell.So the detection of token cell is very fast with forwarding, has avoided causing owing to these problems the reduction of token-ring network efficient.According to the load condition of network, dynamically adjust Max_Length simultaneously,, improve the efficient of looped network when underloading,, reduced the average latency when the network heavy duty simultaneously by reducing the Max_Length value by increasing the Max_Length value.

5. system reliability height

By making up two-way double loop network, self-healed protection can be provided, under the situation that ONU node or communication link break down, each node traffic is unaffected.

The maximum cell number of transmission and the corresponding relation between the Max_Length binary-coded information of allowing of table 1

Allow to send maximum number	Max_Length value (16 system)
		????1	????0X0101H
????2	????0X020XH
		????4	????0X0404H
????8	????0X0808H
		????16	????0X1010H
????32	????0X2020H
		????64	????0X4040H
????128	????0X8080H
		????256	????0X0000H

Though the preferred embodiments of the present invention represent and illustrate,, should be known in that those skilled in the art can change and modification under the condition that does not deviate from spirit of the present invention, scope of the present invention is defined by the claims.

Claims (17)

1. ATM token-ring network, constitute by two kinds of different functional units of optical line terminal OLT and optical network unit ONU, there is and has only an OLT unit on the ring, its major function is to be responsible for the importing of the outer cell of ring and the derivation of the interior cell of ring, be responsible for the management and the configuration of looped network simultaneously, wherein OLT a management and maintenance that critical function is token cell and maximum length indication information element, the derivation of this node cell is responsible in each ONU unit of on the ring other, and insert the cell of this section dot generation and transmit the cell that does not belong to this node according to certain algorithm, it is characterized in that said ATM token-ring network comprises:

A kind of token technology of in the ATM looped network, using;

A kind of to the maintenance of token cell, management strategy;

A kind of cell of using in looped network sends dispatching algorithm;

A kind of method that in the ONU unit, realizes above-mentioned cell transmission dispatching algorithm;

A kind of detection method of token cell;

A kind of generation of token cell and sending method;

A kind of load weight according to looped network, dynamically adjusting each ONU node, to allow to send non-real-time service during holding the token cell be the strategy of data service cell number.

2. according to the ATM token-ring network of claim 1, it is characterized in that, said token technology is, in the ATM token-ring network, OLT is responsible for generating, safeguarding token cell and maximum length indication information element, and and if only if for each ONU node when receiving the token cell, and just the non-real-time service that can send in looped network by this section dot generation is the data service cell, ONU is during holding the token cell, and the non-real-time service that is sent is that the maximum number of cell of data is determined by the maximum length indication information element.

3. according to the ATM token-ring network of claim 1 or 2, it is characterized in that, the token cell be a kind of be the ATM cell of particular value with VPI/VCI (Virtual Path Identifier/Virtual channe identifiers) thresholding or with GFC (universal flow control) thresholding.

4. according to the ATM token-ring network of claim 1 or 2, it is characterized in that having comprised the non-real-time service that the ONU node can send during once holding the token cell in the payload field of maximum length indication information element is the coded message of data service cell maximum number.

5. according to the ATM token-ring network of claim 1, it is characterized in that, said to the token cell safeguard, management strategy is:

OLT by software control, sends a token cell at the looped network initial phase in looped network, i.e. the insertion of token cell, and after this system enters normal operating conditions;

When operate as normal, and if only if OLT is during from upstream detection to the token cell, just downstream node transmission a token cell, the i.e. forwarding of token cell in ring again;

In ring, lose and cause the looped network can't operate as normal for fear of the token cell, in OLT, when in ring, sending a token cell, no matter be to insert also to transmit, all start a timer, if timer expiry does not still detect the token cell, then think the token cell the ring in lose;

Confirming under the situation that the token cell is lost that utilize timer expiry information to trigger the process that sends a token cell in ring, i.e. the regeneration of token cell is reported this incident to high level simultaneously in ring;

Improper overtime in order to prevent timer, the timing of the timer that when OLT detects the token cell, need stop and reset;

Simultaneously in order to prevent because equipment fault or because transmission error code etc. are former thereby cause unexpectedly having generated the token cell in ring, cause and in looped network, have two or more token cells simultaneously, OLT need carry out the deletion action of token cell, promptly in a period of time, even when OLT detects the token cell, in ring, do not transmit the token cell yet, so just can delete all the token cells in the ring;

After after a while, when be sure oing not had the token cell in the looped network, in looped network, insert a token cell,

OLT can be termly, artificially or when receiving specific warning information, carry out the deletion action of token cell from ONU,

In ONU, when detecting the token cell, if it is that the data service cell will send that this ONU node does not have non-real-time service, send a token cell so immediately to downstream node, if non-real-time service is arranged in this ONU node is the data service cell wait to be sent, so, this ONU node will temporarily be held the token cell, to finish be the non-real-time service formation when empty up to all cells in the non-real-time service formation are all sent, or the non-real-time service formation is that non-NULL but the quantity of the non-real-time service cell that this ONU node sends during holding the token cell are when having reached the current maximum that allows of system, just send the token cell to downstream node

If the ONU node during holding the token cell, receives a token cell again, illustrate then on looped network, to have two or more cells that ONU need report this incident to OLT.

6. according to the ATM token-ring network of claim 5, the deletion action that it is characterized in that said token cell can have three kinds of triggering modes, the one, periodically trigger, another is to trigger when OLT receives special warning information from ONU, the third is to trigger artificially, promptly, trigger this incident by the control desk order.

7. according to the ATM token-ring network of claim 5, it is characterized in that, be to detect on the interface of physical chip and ATM layer chip to the detection of token cell, and this token cell that is detected is dropped at the ATM layer.

8. according to the ATM token-ring network of claim 1, it is characterized in that, send in the dispatching algorithm at said cell, priority order is that the priority of token cell is the highest, the priority of real time business is taken second place, from upstream node receive but the priority that do not belong to all ATM cell of this node take second place again, and that the non-real-time service of this section dot generation is the priority of data service cell is minimum.

9. according to the ATM token-ring network of claim 1, it is characterized in that the said method that in the ONU unit, realizes described cell transmission dispatching algorithm, the core of this method is the arbitration logic unit that acts on the interface of physical chip and ATM layer chip, its essence is when existing high priority to send request, the shielding low priority sends request, thereby guarantees that the high priority cell preferentially sends.

10. according to the ATM token-ring network of claim 1, the detection method that it is characterized in that said token cell realizes fast detecting by hardware, concrete method is to utilize SOC (cell begins) signal and clock signal on the UTOPIA of physical chip and ATM layer chip (ATM universal test and operation-interface) interface, latch VPI/VCI or GFC field in the header, then or carry out logical operation or adopt way relatively to detect the token cell.

11. ATM token-ring network according to claim 1, the generation and the sending method that it is characterized in that said token cell are, in OLT and ONU, in order in time to send the token cell to downstream node, adopt the method for hardware to generate the token cell fast, in order to simplify hardware designs, need only preceding 5 bytes that generate the token cell with hardware, and payload part can be filled with any content; The appropriate handshake of the also responsible generation of token cell maker simultaneously promptly sends request with corresponding cell as required and is changed to effectively.

12. ATM token-ring network according to claim 1, it is characterized in that it is the strategy of data service cell number that each ONU node of said dynamic adjustment allows to send non-real-time service during holding the token cell, this strategy comprises, OLT is according to the load condition of looped network or according to the specific warnings information of each ONU that receives, adjusting each ONU node real-time dynamicly by the maximum length indication information element, to allow the maximum number of the non-real-time service cell that sends during once holding the token cell be Max_Length value, and Max_Length is carried by the payload field of maximum length indication information element.

13. the ATM token-ring network according to claim 13 is characterized in that the execution of the reception of maximum length indication information element, understanding and corresponding actions is finished by high layer software.

14. the ATM token-ring network said as claim 1, it is characterized in that in the ATM looped network, using the token cell, OLT is responsible for maintenance, the management of token cell, if and only if for each ONU node on the ring when receiving the token cell, and just can send the limited non-real-time service of number is the data service cell.

15. the ATM token-ring network said as claim 1, the maintenance, the management strategy that it is characterized in that the token cell, in the looped network starting stage, OLT inserts the token cell in looped network, when operate as normal, and if only if when OLT detects the token cell, just forwarding token cell in ring again, simultaneously OLT can also be termly, artificially or when receiving specific warning information, carry out the deletion action of token cell, each ONU unit uses and responsible forwarding token cell ring on.

16. the ATM token-ring network said as claim 1, it is characterized in that generating the token cell with hardware speed and conveniencely, generate simultaneously appropriate handshake (promptly send the token cell when needed and send request) as required, in this method, need only the header that produces the token cell, and payload part can be filled with any content.

17., it is characterized in that the ATM token-ring network is supported two-way dicyclo networking mode in order to improve the reliability and security of system as the said ATM token-ring network of claim 1.When certain node device or certain section communication link broke down, the ATM token-ring network provided the self-healed protection function, thereby guaranteed that communication still can carry out.

Images