Summary of the invention
The technical problem to be solved in the present invention provides a kind of method and optical line terminal that carries out the optical network unit allocated bandwidth, saves the expense of upstream bandwidth.
In order to address the above problem, the invention provides a kind of optical line terminal that carries out the optical network unit allocated bandwidth, comprising: Bandwidth estimation module, bandwidth calculation module and bandwidth determination module; Described Bandwidth estimation module is used for estimating the up expense and the demand payload flow of described optical network unit and notifying extremely described bandwidth calculation module according to the upstream data flow of optical network unit; Described bandwidth calculation module, the up expense and the demand payload flow rate calculation that are used for according to the described optical network unit of described Bandwidth estimation module output are the bandwidth of described each professional container allocation of optical network unit; Described bandwidth determination module is used for being each professional container allocation bandwidth in the described optical network unit in the bandwidth of downlink frame.
Further, above-mentioned optical line terminal also has following characteristics:
Described Bandwidth estimation module is estimated the up expense overhead (n+1) of n+1 Dynamic Bandwidth Allocation cycle time network element according to following formula:
overhead(n+1)=Grant(n-1)-pm(n+1)-idle(n+1);
Grant (n-1) be meant n-1 Dynamic Bandwidth Allocation during the cycle described optical line terminal be the bandwidth of each the professional container allocation in the described optical network unit; Pm (n+1) is meant the upstream quantitative statistics value that n+1 Dynamic Bandwidth Allocation cycle time network element sends to optical line terminal; Idle (n+1) refers to the statistical value of n+1 Dynamic Bandwidth Allocation cycle time network element to the idle data of optical line terminal transmission, and n is the integer greater than 1.
Further, above-mentioned optical line terminal also has following characteristics:
Also comprise the main control module that links to each other with described bandwidth calculation module; Described main control module is used for determining the position of data in uplink frame of described each professional container of optical network unit; Described bandwidth calculation module, the position that also is used for according to each definite professional container of described main control module is that described optical network unit distributes bandwidth.
Further, above-mentioned optical line terminal also has following characteristics:
Described main control module also is used for just being arranged in order the position of each professional container in the same burst of uplink frame according to the priority of the professional container of described optical network unit; Perhaps, the professional container of limit priority is set in separately in the burst, the professional container of other non-limit priority is set in other one or more bursts.
Further, above-mentioned optical line terminal also has following characteristics:
Described bandwidth calculation module also is used to the distribution bandwidth of each professional container to be the multiple of 255 bytes; The expense that comprises the physical layer overhead byte for the bandwidth of the professional container allocation of the burst primary importance that is arranged in uplink frame.
Further, above-mentioned optical line terminal also has following characteristics:
Described bandwidth calculation module, also be used to the distribution bandwidth of each professional container be the multiple of 255 bytes and deviant delta byte and, delta is less than 239 integer greater than 16; For the value of delta in the bandwidth of each professional container allocation does not fall into value under the condition in the check byte scope satisfying bursty data.
In order to address the above problem, the present invention also provides a kind of method of carrying out the optical network unit allocated bandwidth, comprise: up expense and the demand payload flow of estimating optical network unit according to the upstream data flow of optical network unit, up expense and demand payload flow rate calculation according to described optical network unit are the bandwidth of each professional container allocation in the described optical network unit, are each professional container allocation bandwidth in the described optical network unit in the bandwidth of downlink frame.
Further, said method also has following characteristics:
Estimate the up expense overhead (n+1) of n+1 Dynamic Bandwidth Allocation cycle time network element according to following formula:
overhead(n+1)=Grant(n-1)-pm(n+1)-idle(n+1);
Grant (n-1) be meant n-1 Dynamic Bandwidth Allocation during the cycle described optical line terminal be the bandwidth of each the professional container allocation in the described optical network unit; Pm (n+1) is meant the upstream quantitative statistics value that n+1 Dynamic Bandwidth Allocation cycle time network element sends to optical line terminal; Idle (n+1) refers to the statistical value of n+1 Dynamic Bandwidth Allocation cycle time network element to the idle data of optical line terminal transmission, and n is the integer greater than 1.
Further, said method also has following characteristics:
Described optical line terminal is determined the position of data in uplink frame of each professional container in the described optical network unit; And be that described optical network unit distributes bandwidth according to the position of each professional container of determining.
Further, said method also has following characteristics:
Optical line terminal just is arranged in order the position of each professional container in the same burst of uplink frame according to the priority of professional container in the described optical network unit; Perhaps, the professional container of limit priority is set in separately in the burst, the professional container of other non-limit priority is set in other one or more bursts.
Further, said method also has following characteristics:
Described optical line terminal is the multiple of 255 bytes for the distribution bandwidth of each professional container; The expense that comprises the physical layer overhead byte for the bandwidth of the professional container allocation of the burst primary importance that is arranged in uplink frame.
Further, said method also has following characteristics:
Described optical line terminal is 255 bytes for the distribution bandwidth of each professional container multiple and deviant delta byte with, delta be less than 239 integer greater than 16; For the value of delta in the bandwidth of each professional container allocation does not fall into value under the condition in the check byte scope satisfying bursty data.
The invention provides a technical scheme of in GPON, supporting uplink burst and FEC function, the realization that this technical scheme can the desired correlation function of supported protocol; Healthy and strong performance when this scheme has guaranteed transmitting uplink data again when reducing uplink burst data stream expense.Among the present invention, when determining the optical network unit bandwidth, the bandwidth with reference to distributing before this sub-distribution makes the distribution of this bandwidth more excellent.
Embodiment
In order to describe the present invention in detail, the Principle of Communication of OLT and ONU among the present invention is described with Fig. 3 and Fig. 4.
As shown in Figure 3, ONU receives the input data and comprises stable data stream (Constant Bit Rate, be called for short CBR) and data flow (the Variable Bit Rate that happens suddenly, be called for short VBR), be buffered in the memory and and give OLT by the DBRU report reporting with the data in buffer amount, after OLT receives, obtain the bandwidth of distributing into each ONU according to the DBA algorithm, ONU sends the upstream data of some according to the data volume decision of preserving in the bandwidth that is assigned to and the memory to OLT, and the data volume of this upstream data is one minimum in the OLT pairing data volume of upstream bandwidth of distributing and all buffer data sizes.
Fig. 4 has described the sequential relationship of OLT and ONU communication.In (n-1) individual DBA cycle, ONU reports DBRU to report the concurrent capable flow of serving; N DBA cycle, OLT is according to the statistical value of DBA algorithm and DBRU report and uplink traffic, carry out the DBA computing and obtain the bandwidth of distributing into each TCONT among the ONU, so that ONU sends upstream data in (n+1) individual DBA cycle, obviously, the DBRU demand that reports of ONU will just can be responded at two DBA week after dates.
As shown in Figure 5, the optical line terminal that carries out the optical network unit allocated bandwidth in the present embodiment comprises main control module, Bandwidth estimation module, bandwidth calculation module, bandwidth determination module.
Main control module is used for determining the position of data in uplink frame of each professional container of optical network unit.Concrete, just be arranged in order the position of each professional container in the same burst of uplink frame according to the priority of professional container in the described optical network unit; Perhaps, the professional container of limit priority is set in separately in the burst, the professional container of other non-limit priority is set in other one or more bursts.
Main control module also is used for notifying the maximum of the bandwidth that current optical network unit can be assigned with and the information such as priority level of optical network unit to bandwidth calculation module; Also be used for the sequential that control bandwidth computing module and bandwidth determination module are operated.
Bandwidth estimation module is used for estimating the up expense and the demand payload flow of described optical network unit and notifying to bandwidth calculation module according to the upstream data flow of optical network unit.
Bandwidth calculation module, the up expense and the demand payload flow rate calculation that are used for according to the optical network unit of Bandwidth estimation module output are the bandwidth of described each professional container allocation of optical network unit, and the position of each professional container of determining according to described main control module is that described optical network unit distributes bandwidth.
Concrete, Bandwidth estimation module is estimated the up expense overhead (n+1) of n+1 Dynamic Bandwidth Allocation cycle time network element according to following formula:
overhead(n+1)=Grant(n-1)-pm(n+1)-idle(n+1);
Grant (n-1) be meant n-1 Dynamic Bandwidth Allocation during the cycle described optical line terminal be the bandwidth of each the professional container allocation in the described optical network unit; Pm (n+1) is meant the upstream quantitative statistics value that n+1 Dynamic Bandwidth Allocation cycle time network element sends to optical line terminal; Idle (n+1) refers to the statistical value of n+1 Dynamic Bandwidth Allocation cycle time network element to the idle data of optical line terminal transmission, and n is the integer greater than 1.
The estimation of optical network unit demand payload flow is a prior art, repeats no more.
Bandwidth calculation module makes bursty data not fall into the interior condition of check byte scope, also be used to the distribution bandwidth of each professional container to be the multiple of 255 bytes, the bandwidth of professional container allocation that is arranged in the burst primary importance of uplink frame comprises the expense of PLOU byte; Perhaps, for the distribution bandwidth of each professional container be the multiple of 255 bytes and deviant D byte and, D is less than 239 integer greater than 16; For the value of D in the bandwidth of each professional container allocation does not fall into value under the condition in the check byte scope satisfying bursty data.
The bandwidth determination module, be used for being each professional container allocation bandwidth in the described optical network unit in the bandwidth of downlink frame, generate the table of articles of each professional container, this professional container of indication is allowed to send the zero-time and the concluding time of upstream data in the table of articles in uplink frame, and by sending module this information is notified to optical network unit by downlink frame, notify it to send the time and the position of upstream data.
Among the present invention, the method of carrying out the optical network unit allocated bandwidth comprises: estimating the up expense of optical network unit according to the upstream data flow of optical network unit, is the bandwidth of each professional container allocation in the optical network unit according to the up expense and the demand payload flow rate calculation of optical network unit; It in the bandwidth of downlink frame each professional container allocation bandwidth in the optical network unit.
Concrete, estimate the up expense overhead (n+1) of n+1 Dynamic Bandwidth Allocation cycle time network element according to following formula:
overhead(n+1)=Grant(n-1)-pm(n+1)-idle(n+1);
Grant (n-1) be meant n-1 Dynamic Bandwidth Allocation during the cycle described optical line terminal be the bandwidth of each the professional container allocation in the described optical network unit; Pm (n+1) is meant the upstream quantitative statistics value that n+1 Dynamic Bandwidth Allocation cycle time network element sends to optical line terminal; Idle (n+1) refers to the statistical value of n+1 Dynamic Bandwidth Allocation cycle time network element to the idle data of optical line terminal transmission, and n is the integer greater than 1.
Also determine the position of data in uplink frame of each professional container in the optical network unit in the optical line terminal.For example, comprise two bits in the information of the professional container of each of indication, one is SOB (start ofburst), and one is EOB (end of burst); Wherein SOB is that the corresponding TCONT of 1 expression is the beginning of a burst; EOB is that the corresponding TCONT of 1 expression is the ending of a burst.If current TCONT is in the foremost of the TCONT of ONU chained list, SOB should be configured to 1 so; If current TCONT at the TCONT of ONU chained list backmost, LOB should be configured to 1 so; If current TCONT is in the centre of the TCONT of ONU chained list, SOB and LOB should all be configured to 0 so, as shown in Figure 6A.The included TCONT of SOB and EOB has just formed burst data of uploading in chained list; And if only if, and SOB is set at 1 o'clock, the bandwidth that OLT just can distribute PLOU to use for this TCONT, and other TCONT will share this PLOU byte.
Optical line terminal is that optical network unit distributes bandwidth according to the position of each professional container of determining.Mode one can just be arranged in order each professional container position in the same burst of uplink frame according to the priority of professional container in the optical network unit; Mode two can also be set in the professional container of limit priority separately in one the burst, and the professional container of other non-limit priority is set in other one or more bursts.
Three TCONT of ONU1 are respectively Class1, type 2 and type 3, and three TCONT of ONU2 are respectively Class1, type 4 and type 5, and wherein the TCONT of Class1 is very high to the requirement of the shake of the data of transmission in actual applications; In the method for salary distribution of the mode one as shown in Fig. 6 B, thereby ONU1/ONU2 has formed the minimum that a burst has reached the PLOU bandwidth cost of system respectively.Shown in Fig. 6 C in the method for salary distribution of mode two, two ONU have formed four burst, two foremosts that all formed two burst independently for the TCONT of type1 and be arranged in chained list, such configuration mode, though brought certain overhead, guaranteed that effectively two are dithered as zero for the TCONT of type1.But below only just illustrate the diversity of TCONT in the distribution locations of uplink frame burst, specific implementation is including but not limited to above giving an example.
By the formula of describing in the said method as can be known, no matter whether the FEC function enables, in Bandwidth estimation module, directly can accurately estimate the expense of the data uploaded with formula (1), because in a frame, other bandwidth except payload and data all are taken as expense, comprising: PLOU, PLOAM, DBRU, GEM header, FEC CRC etc.
At when the FEC function is enabled, the beginning of upstream data and the sign of ending can not drop on the verification zone of FEC, the present invention proposes following two kinds of implementations;
Mode one: the multiple that is 255 bytes for the distribution bandwidth of each professional container; The expense that comprises the PLOU byte for the bandwidth of the professional container allocation of the burst primary importance that is arranged in uplink frame.
When the FEC function is enabled, bandwidth calculation module rounds up the distribution bandwidth of each TCONT and normalizes to the multiple of 255 bytes, simultaneously can do fine setting because of section to bandwidth, thereby the sign of the beginning of data and ending does not drop on the verification zone of FEC when guaranteeing that the final multiple that distributes the bandwidth of going down to be 255bytes allows FEC open at the bandwidth determination module; The specific implementation step is as follows:
Bandwidth calculation module produces two kinds of TCONT allocation result:
1.SOB=1 TCONT, comprise the expense plo_bytes of PLOU in the bandwidth of distribution
Bandwidth calculation module is distributed bandwidth=255n+plo_byte-3
2.SOB=0 TCONT, do not comprise plo_bytes in the bandwidth of distribution
Bandwidth calculation module is distributed bandwidth=255n
In the bandwidth determination module, at the afterbody of each frame, because the byte of afterbody is limited, the bandwidth that belongs to some TCONT may be cut into two; When the bandwidth determination module is handled, two kinds of situations are arranged:
If the TCONT for SOB=1 does not cut into slices, distribute the stop-start=255n-3 of the bandwidth of going down so; If section, first is at the stop-start=255m-3 of the bandwidth of the clauses and subclauses of present frame, second clauses and subclauses stop-start=255 (n-m)-3 that belongs to next frame, and second access clauses and subclauses get in the total bandwidth (plo_byte-3) byte for the PLOU expense with distributing.
If the TCONT for SOB=0 does not cut into slices, so stop-start=255n; If section, first clauses and subclauses stop-start=255m, second clauses and subclauses stop-start=255 (n-m)-3, and second access clauses and subclauses got (plo_byte-3) byte for PLOU expense usefulness in total bandwidth.
That is to say, as long as the access entry length of band plo_bytes is exactly 255n-3, otherwise be exactly the 255n byte.
Mode two: for the distribution bandwidth of each professional container be the multiple of 255 bytes and deviant delta byte and, delta is less than 239 integer greater than 16; For the value of delta in the bandwidth of each professional container allocation does not fall into value under the condition in the check byte scope satisfying bursty data.
In specific implementation, the distribution bandwidth of each TCONT also can be the form of 255n+delta (16<delta<239), and wherein delta is a parameter that can dispose; Bandwidth calculation module will guarantee that start and stop do not drop in the check byte scope when distributing bandwidth, and last delta of whole burst is greater than 16 and less than 239 bytes.In case concrete implementation method is to find that stop just drops in the check byte scope stop is carried out the requirement that backward fine setting makes it protocol compliant; Be exemplified below: such as an ONU has three TCONT, is respectively t1, t2 and t3; The bandwidth that bandwidth calculation module calculates is 250bytes, 30bytes and 220bytes, the stop pointer of t1 should be fine-tuning to the 255bytes place so, the stop pointer of t2 should be at (255+30) bytes place, and the stop pointer of t3 should be at (255+30+225) bytes place.The frame place will not drop on the check byte scope with start and stop be that principle continues to carry out similarly fine setting for the second time in section place to the bandwidth determination module to passed the bandwidth come by bandwidth calculation module striding; Concrete step can when burst does not finish, be calculated the pointer position of each TCONT referring to Fig. 7, if the stop pointer of a certain TCONT drops in the verification zone, overabsorption tconti one point bandwidth then is adjusted to its stop pointer beyond the verification zone.After burst finishes, be judged as bandwidth that TCONT distributes when the intersection of front and back frame, check among the burst whether the stop pointer of the TCONT of a frame is moved to the verification zone in the back, if, to its stop pointer fine setting.Can see that at Fig. 7 in case the bandwidth of certain TCONT is cut into slices, the stop pointer of whole TCONT of a frame is because the start pointer has made zero again and may need to readjust so in the back.
In superincumbent two kinds of methods, first method distributes the granularity of bandwidth bigger, and bandwidth waste is many; The two-wheeled trim process process more complicated of the bandwidth of second method.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.