CN1152488C - Method for measuring distance in passive optical ATM network - Google Patents
Method for measuring distance in passive optical ATM network Download PDFInfo
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- CN1152488C CN1152488C CNB011153911A CN01115391A CN1152488C CN 1152488 C CN1152488 C CN 1152488C CN B011153911 A CNB011153911 A CN B011153911A CN 01115391 A CN01115391 A CN 01115391A CN 1152488 C CN1152488 C CN 1152488C
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Abstract
The present invention discloses a method for realizing the distance measurement in ATM passive optical networks. The present invention has the key that the method at least comprises the following steps: a, an optical line terminal (OLT) sends a configuring message of distance measurement to an optical network unit (ONU); b, the OLT opens distance measurement windows, waits for trapping distance measurement physical layer operation maintenance management (PLOAM) sent by an optical network unit and begins timing; c, when the PLOAM is trapped, timing is stopped, and the validity of the distance measurement result is judged; d, if three times of distance measurement fail, distance measurement is finished, and failure reasons are informed to network management; otherwise, the method returns to the step b; if three times of distance measurement succeed, equivalent delaying values are calculated and adjusted according to the distance measurement results, the OLT sends a configuring message of distance measurement finish to the ONU, and the ONU sends a response message after the ONU receives the message; if ONU sends no response message, distance measurement is considered to fail, distance measurement is finished, and failure reasons are informed to network management; otherwise, the method returns to the step b.
Description
Technical field
The present invention relates to the ranging technology in the ATM Passive Optical Network, refer to especially a kind ofly can be in ATM Passive Optical Network realize farthest guaranteeing the distance-finding method of quality of service in the range finding between optical line terminal (OLT) and the optical network unit (ONU).
Background technology
Because the arrival of network times, the communication network develop rapidly that various functions are become stronger day by day is to satisfy the demand that people grow with each passing day.ATM Passive Optical Network (APON) is exactly one of them, it is that ATM broadband services and EPON (PON) technology based on the cell transmission are combined, with optical fiber as transmission medium, the communication network that can provide high-speed data and broadband services to handle, bandwidth, capacity are big.So-called PON is exactly between optical line terminal (OLT) and optical network unit (ONU), just between local side and remote subscriber, without any the optical access network of active electronic equipment.An OLT can connect a plurality of ONU simultaneously in APON, and therefore, APON not only can provide broadband multimedia services more neatly, and allows a plurality of users in the Access Network to share whole bandwidth.
Local side OLT is connected with light distributor by optical fiber with each far-end ONU in the APON system, because each ONU is to the logical reach difference of OLT, the data phase that can cause being arrived OLT by different ONU has nothing in common with each other, and the result causes each ONU to arrive the data collision of OLT, causes loss of data.For guaranteeing that each ONU keeps identical on logical reach, make each ONU data not inserted local side with conflicting according to certain phase place, just adopt the method for range finding to address this problem, realize the measurement of distance between OLT and the ONU.
At present, G.983.1 ITU-T standard that APON is released has and G.983.2, has defined the standard of transmission medium layer respectively; And the standard of top management entity interface.Wherein, the transmission medium layer is divided into Transmission Convergence Sub-layer (TC layer) and physical media layer two parts again, and G.983.1 range finding promptly belongs to the part to TC layer standard.
According to G.983.1 definition to finding range, the range finding flow process that it is concrete and OLT that is correlated with finding range and the relation between the phase bit specifications point between the ONU, as shown in Figure 1.In Fig. 1, TiS1 and TiS2 represent local side electricity/light conversion time delay; Tpd represents the propagation delay time of signal on optical fiber; TiO1 and TiO2 represent far-end electricity/light conversion time delay; Ts is basic cell propagation delay time, is produced by the PON signal processing among the ONU; The equivalent delay value of Td for obtaining by range finding and conversion, 0≤Td in the 155Mbps system≤32000bit.Tconst is the identity logic distance that each ONU of regulation will reach, and 4T (50 kilometers) and two kinds of specifications of 2T (25 kilometers) are generally arranged; T
ResponseBe the response time of ONU.According to above-mentioned parameter, the T of Tconst and each ONU
ResponseValue should be:
Tconst＝TiS1+Tpd+TiO1+Ts+Td+TiO2+Tpd+TiS2
T
Response＜ONU 〉=TiO1+Ts+Td+TiO2
Work as Td=0, when promptly not finding range,
T
Response＜ONU 〉=TiO1+Ts+TiO2
Under normal operating condition,, identical constant Tconst all should be arranged for the balanced round-trip delay of all ONU promptly for the ONU behind the ranging success.That is to say the ONU for all normal operating conditions, they have identical logical reach, and the ONU of each operate as normal just can not insert data in the OLT side with conflicting like this.
In ranging process, OLT also needs to open ranging window except to ONU issues configuration messages.This ranging window masks a certain section bandwidth of circuit in fact exactly, so that tested ONU can appear in this section shielding section to range finding physical layer operations management maintenance (PLOAM) cell that OLT sends out and not be subjected to the influence of other data, when the TC layer of OLT finishes range-viewfinder according to the cell of catching then, thereby obtain the time-delay of circuit and processing, at last calculate required Td, and be handed down to ONU according to this time-delay.
But, present range finding flow process is just measured the delay value of each ONU and the legitimacy of delay value is not provided definite Rule of judgment, in G.983.1, propose in three ranging process, as long as the difference of twice range finding delay value is just thought success less than certain scope.If but in fact the delay value that obtains of range finding has surpassed 4T, and three delay values are the same, ranging success outwardly, but in fact this moment, delay value was illegal.If delay value is illegal, will causes ONU to insert the mistake of data phase, and then badly influence the access of other ONU data to OLT.In addition, also not to the judgement of ONU running status, so, might cause the faulty operation of OLT in the existing range finding flow process to ONU.Because, OLT needs ONU behind ranging success the message of local side configuration to be responded, if ONU does not have response, though ONU ranging success then, and OLT thinks that still this ONU is in abnormal condition, and so, OLT is in order to guarantee the operation of system, will the ONU of this non-normal working be handled accordingly, so will produce mistake and handle.
Also have, in ranging process, can take a part of fixed-bandwidth more or less, thereby influence those business time delay and jitter-sensitive.If the fixed-bandwidth of an ONU is big more, it under the situation of frequent range finding, will affect to business so owing to the fixed-bandwidth loss that range finding causes is also just many more, damage quality of service (QOS).
Summary of the invention
In view of this, main purpose of the present invention is to provide the implementation method of finding range in a kind of ATM Passive Optical Network, makes that the reliability and the accuracy of range finding are higher, makes ONU can enter normal operating conditions fast after range finding, and then the normal operation of the system of assurance.
For achieving the above object, technical scheme of the present invention is achieved in that
The implementation method of finding range in a kind of ATM Passive Optical Network comprises the steps: at least
A. optical line terminal (OLT) is sent out the configuration messages of range finding to optical network unit (ONU);
B. optical line terminal (OLT) is opened ranging window, waits for that catching optical network unit (ONU) goes up the range finding physical layer operations maintenance management of sending out (PLOAM), and picks up counting;
C. optical line terminal (OLT) captures optical network unit (ONU) and goes up the range finding physical layer operations maintenance management of sending out (PLOAM), stops timing;
D. judge whether this delay value obtains at the appointed time,, then finish range finding if delay value does not obtain at the appointed time; If delay value obtains at the appointed time, judge again then whether this delay value is in the ranging window of being opened, if delay value is not in the ranging window of being opened, then finish range finding; If delay value is in the ranging window of being opened, then judge adjacent twice time-delay value difference more whether in fixed range, if not in fixed range, then the number of times of range finding failure adds one, judging whether three range finding failures then, enters step e; If adjacent twice time-delay value difference is in fixed range, then the number of times of ranging success adds one, judges whether three ranging success then, enters step f;
If e. three range finding failures then finish range finding and notice webmaster failure cause; Otherwise, return step b;
If f. three ranging success then enter step g; Otherwise, return step b;
G. optical line terminal (OLT) calculates and adjusts equivalent delay value according to the range finding result, and optical line terminal (OLT) issues the configuration messages that finishes range finding to optical network unit (ONU), and optical network unit (ONU) is received to beam back after this message and answered message;
H. optical line terminal (OLT) is received receiveing the response of optical network unit (ONU), notice webmaster ranging success, and the running status that ONU is set is a normal operating conditions; Otherwise optical line terminal (OLT) issues abnormal running message, notice webmaster failure cause, and finish range finding.
This method also further comprises the steps: if ranging success for the first time, and optical line terminal (OLT) is opened ranging window again by primary range finding result.
Stipulated time described in the steps d is 300ms.Fixed range described in the steps d is 2bit.Range finding result described in the step g is three results' that successfully find range a mean value.
By such scheme as seen, the implementation method of finding range in the ATM Passive Optical Network provided by the present invention, the judgement that in ranging process, has added the delay value legitimacy that range finding is obtained, and to the judgement of ONU running status, like this, just can make resulting delay value reliability of range finding and accuracy higher, can not cause ONU to insert error in data owing to the illegal property of delay value to OLT.Can make ONU can enter normal operating conditions fast after range finding, not response in time of ONU does not have influence on the normal process of OLT to ONU, and causes system's operation to go wrong after can not finishing because of range finding yet.In addition, the present invention can also add the processing of bandwidth compensation in ranging process, makes by the range finding window data of flooding to have an opportunity to send, and reducing the influence of ranging process to business, thereby reaches the purpose that improves QoS.
Description of drawings
Fig. 1 be G.983.1 in regulation with relevant OLT of range finding and ONU between concern schematic diagram between phase bit specifications point;
OLT was to the configuration messages schematic diagram that is issued by range finding ONU when Fig. 2 prepared to find range for the present invention;
Fig. 3 is for obtaining the configuration messages schematic diagram that legal time-delay back OLT issues to ONU;
Fig. 4 is transported to the response message schematic diagram of putting message for the legal time-delay of acquisition back ONU to OLT;
The flow chart that Fig. 5 realizes for distance-finding method of the present invention.
Embodiment
Relevant detailed description of the present invention and technology contents, conjunction with figs. is described as follows:
See also shown in Figure 5ly, ranging process of the present invention mainly comprises following several stages:
(1) OLT is by descending PLOAM cell, to being issued configuration messages by range finding ONU.As shown in Figure 2, configuration messages comprises up Rx control messages Upstream_Rx_Control, up Overhead Message Upstream_Overhead, distributes PON_ID message Assign_Pon_ID and authorized appropriation message Grant_Allocation.After these four message were handed down to ONU, tested ONU was according to the variation of the message traction state machine that receives, and up expense, PON_ID, data grant and the PLOAM mandate of disposing this locality according to message content.
(2) open ranging window.The purpose that ranging window launches is not allow ONU upwards to insert data a certain section bandwidth on the circuit, because the position of tested ONU is uncertain, so its optional position after the range finding PLOAM cell that OLT sends may appear at the range finding beginning.If in the ranging window of opening, fallen into cell of data, common PLOAM cell etc. when OLT receives, will obtain inaccurate range finding result.Therefore OLT does not send out permission any and gives ONU in one section bandwidth, to avoid the generation of above-mentioned situation.Generally, open for the first time ranging window and be the distance windowing then of estimating ONU, greatly about 15 kilometers, so just can open 10～20 kilometers window such as ONU; If but do not know that about position of ONU can open 0～50 kilometer window, would be substantially equal to Tconst.And the fixed-bandwidth of loss this moment can be remedied in the step of the 5th part bandwidth compensation.
(3) repeatedly the range finding delay value legitimacy of finding range is simultaneously judged.Carry out the range finding first time earlier, promptly the TC layer of OLT is caught ONU and is gone up the range finding PLOAM that sends out, and when catching back constipation bundle range-viewfinder, and judges whether this delay value is legal.Because G.983.1 if the regulation legal range finding delay value that obtains three successes is just thought and is obtained the delay value success, therefore, delay value is legal if find range for the first time, be that benchmark is opened less ranging window and carried out second, third time range finding just with the delay value that obtains for the first time, because this moment, the position of ONU was roughly determined, can reduce the taking of fixed-bandwidth, obtain judging its legitimacy behind the delay value.Each judge the range finding delay value whether legal main need to confirm following some:
A. judge whether to obtain at the appointed time delay value? suggestion 300ms is the maximum latency of response in G.983.1.If do not meet, must stop range finding at once.
B. judge the delay value obtain whether greater than the minimum value of ranging window, less than the maximum of ranging window because if the delay value that records has exceeded ranging window defined scope, the delay value that obtains is exactly illegal, just might cause gross error if still be considered to right value.Therefore, if do not meet, must stop range finding at once.
Within the specific limits whether the difference of c. judging the adjacent delay value that records for twice? it is definite that this certain limit is pressed bit, advises that G.983.1 the delay value to obtain for the first time is a standard, and the delay value that the back range finding obtains and its be the poor 2bit that is no more than relatively generally.
If the condition above not satisfying is so just thought when time acquisition delay value failure.If failure is just thought for three times to the range finding failure of this ONU.
(4) if obtained legal delay value, then OLT just issues a series of configuration messages to ONU and finishes whole ranging process.
After obtaining legal delay value, the configuration messages that OLT issues to ONU comprises as shown in Figure 3: range finding time message Ranging_Time, be handed down to this ONU with the delay value that records by this message; Configuration VP/VC message Config_VP/VC, configuration VP/VC is used for in-band communications; Whether stir VP message Churned_VP decision encrypts this VP.BER is message Ber_interval at interval, and how long decision ONU is to error code of OLT newspaper.Divide time slot authorization configuration message Divided_Slot_Grant_Config, the branch time slot License Value, the mini-slot that dispose this ONU meet length and side-play amount thereof.
If the range finding failure then issues release PON_ID message Deactive_Pon_ID, to the ONU deexcitation of appointment, so that this ONU can accept to find range next time.
Need to prove that ONU must respond Config_VP/VC, Churned_VP and Ber_interval, that is to say when ONU receives these message, send Acknowledge_Config_VP/VC, Acknowledge_Chumed_VP and Acknowledge_Ber_interval to OLT respectively, as shown in Figure 4.If ONU does not just think that to any bar response in them ONU is in the abnormal running state, then OLT issues Deactive_Pon_ID message, activates the ONU of appointment, and notice webmaster failure cause, finishes range finding simultaneously.If OLT receive ONU all receive the response, think that then the running status of ONU is a normal operating conditions, OLT notice webmaster ranging success, and the running status that ONU is set is a normal operating conditions.
The legal delay value that records according to three successes calculates range finding result's mean value, calculates Td value by this value again, and the Tconst value adjustment Td that should have with reference to this ONU.
In addition, the bandwidth that the present invention is lost in ranging process can be remedied by the method for bandwidth compensation, specific practice is exactly: the fixed-bandwidth size that is calculated loss by ONU, with this part bandwidth join in the highest constant bit rate of priority (CBR) dynamic bandwidth please formation in, distribute bandwidth to it again.So, the damage of the professional QOS that range finding can be caused is reduced to minimum, thereby guarantees professional QOS, also protects user's interests simultaneously.The separate case application of the method for this bandwidth compensation.
Claims (5)
1, the implementation method of finding range in a kind of ATM Passive Optical Network is characterized in that this method comprises the steps: at least
A. optical line terminal (OLT) is sent out the configuration messages of range finding to optical network unit (ONU);
B. optical line terminal (OLT) is opened ranging window, waits for that catching optical network unit (ONU) goes up the range finding physical layer operations maintenance management of sending out (PLOAM), and picks up counting;
C. optical line terminal (OLT) captures optical network unit (ONU) and goes up the range finding physical layer operations maintenance management of sending out (PLOAM), stops timing;
D. judge whether this delay value obtains at the appointed time,, then finish range finding if delay value does not obtain at the appointed time; If delay value obtains at the appointed time, judge again then whether this delay value is in the ranging window of being opened, if delay value is not in the ranging window of being opened, then finish range finding; If delay value is in the ranging window of being opened, then judge adjacent twice time-delay value difference more whether in fixed range, if not in fixed range, then the number of times of range finding failure adds one, judging whether three range finding failures then, enters step e; If adjacent twice time-delay value difference is in fixed range, then the number of times of ranging success adds one, judges whether three ranging success then, enters step f;
If e. three range finding failures then finish range finding and notice webmaster failure cause; Otherwise, return step b;
If f. three ranging success then enter step g; Otherwise, return step b;
G. optical line terminal (OLT) calculates and adjusts equivalent delay value according to the range finding result, and optical line terminal (OLT) issues the configuration messages that finishes range finding to optical network unit (ONU), and optical network unit (ONU) is received to beam back after this message and answered message;
H. optical line terminal (OLT) is received receiveing the response of optical network unit (ONU), notice webmaster ranging success, and the running status that ONU is set is a normal operating conditions; Otherwise optical line terminal (OLT) issues abnormal running message, notice webmaster failure cause, and finish range finding.
2, implementation method according to claim 1 is characterized in that: this method also further comprises the steps: if ranging success for the first time, and optical line terminal (OLT) is opened ranging window again by primary range finding result.
3, implementation method according to claim 1 is characterized in that: the stipulated time described in the steps d is 300ms.
4, implementation method according to claim 1 is characterized in that: the fixed range described in the steps d is 2bit.
5, implementation method according to claim 1 is characterized in that: the range finding result described in the step g is three results' that successfully find range a mean value.
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| CNB011153911A CN1152488C (en) | 2001-04-25 | 2001-04-25 | Method for measuring distance in passive optical ATM network |
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| CNB011153911A CN1152488C (en) | 2001-04-25 | 2001-04-25 | Method for measuring distance in passive optical ATM network |
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| CN1152488C true CN1152488C (en) | 2004-06-02 |
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Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100426741C (en) * | 2005-07-22 | 2008-10-15 | 中兴通讯股份有限公司 | Automatic configurating method for EPON net element device |
| CN1866804B (en) * | 2005-10-19 | 2011-04-20 | 华为技术有限公司 | Method for carrying out fault protection inversion on main stem optical fibre of passive optical network |
| CN101060369B (en) * | 2006-04-17 | 2010-09-08 | 华为技术有限公司 | A method and system for solving the errors under the PON PLOAM system |
| CN101291181B (en) * | 2007-04-19 | 2012-03-21 | 株式会社日立制作所 | Expandable passive optical network equipment having optical network unit with changeable mode |
| CN101290213B (en) * | 2007-04-20 | 2011-12-21 | 华为技术有限公司 | Optical fibre length measurement method, communication apparatus and communicating system |
| CN101179434B (en) * | 2007-10-24 | 2010-06-09 | 中兴通讯股份有限公司 | Automatic time-counting method in network management system |
| CN101465694A (en) * | 2007-12-19 | 2009-06-24 | 深圳华为通信技术有限公司 | Passive optical network system, optical line terminal, authentication information generation and authentication method |
| CN101247665B (en) * | 2008-03-25 | 2010-12-29 | 中兴通讯股份有限公司 | Method for improving gigabit passive optical network reliability |
| CN101257346B (en) * | 2008-04-02 | 2012-12-12 | 华为技术有限公司 | System, apparatus and method for acquiring light path fault location |
| CN101783975B (en) * | 2009-01-16 | 2013-06-12 | 华为技术有限公司 | Method, device and system for measuring distance in communication network |
| CN102075820B (en) | 2009-11-23 | 2015-05-20 | 中兴通讯股份有限公司 | Method and device for measuring distance in passive optical network |
| CN103427900B (en) * | 2012-05-18 | 2015-11-25 | 中国移动通信集团公司 | A kind of asymmetrical compensation of optical fiber, equipment and system |
| US11568420B2 (en) * | 2012-11-21 | 2023-01-31 | Verint Americas Inc. | Analysis of customer feedback surveys |
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