WO2010043128A1

WO2010043128A1 - Method and device for transmitting and receiving mapping overheads

Info

Publication number: WO2010043128A1
Application number: PCT/CN2009/072776
Authority: WO
Inventors: 沈瑶; 苏伟; 向俊凌; 骆彦行; 李扬; 丁炽武
Original assignee: 华为技术有限公司
Priority date: 2008-10-14
Filing date: 2009-07-15
Publication date: 2010-04-22
Also published as: CN101729188A; CN101729188B

Abstract

A method and a device for transmitting and receiving mapping overhead in an adaptive constant bit rate service are provided, in the field of optical transmission networks. They address the problem that the prior art can not provide the same adjustment ability for OPUk and OPUk-Xv and adjustment speed is slow. A method and a device for transmitting and receiving mapping overhead provide the same adjustment ability for OPUk and for OPUk-Xv, and perform arbitrary adjustment of the byte number value of user data within a definite range, through transmitting the variation value of the user data byte number in the OTN frame, conducting majority voting at the receiving end to obtain an accurate user data byte number, and performing flexible mapping adjustments. The technical solutions provided by the embodiments of this invention are suited for use in optical transmission network systems.

Description

Method and device for transmitting and receiving mapping overhead

Technical field

The present invention relates to the field of optical transmission networks, and in particular, to a method and apparatus for transmitting and receiving mapping overhead in an adaptive constant bit rate service.

Background technique

The Digital Wrapper defines an optical network frame format. As shown in Figure 1, each frame is divided into 4 rows and 4080 columns. Header 16 is the overhead area, tail 256 is the FEC (Forward Error Correction) check area, and the middle 3808 is the payload area for placing customer data. 1 to 7 of the first row area is placed overhead frame alignment byte, 8 to 14 is placed an optical channel transport unit (the OTUk) Overhead bytes; 2 ~ ⁴ 1 ~ I 4 lines as the optical channel data unit ( ODUk ) Overhead Byte; The 15th and 16th columns of the 1st to 4th rows place the Optical Channel Payload Unit (OPUk) overhead bytes. When X (X^2) 0TN frames are virtual concatenated, a new virtual concatenation overhead (VC0H) is added to 0PUk-Xv (X virtual concatenated OPUks).

In the mapping method of adaptive CBR (Constants Bit Rate) service, how to transmit the number of bytes Cn transmitted by the client signal in the 0TN frame period has become an important factor affecting the reliability.

In the prior art, a unified optical network frame format is provided for 0PUk/0PUk-Xv, and a new Cbyte field is defined, which illustrates that the transmission mode of Cn is adjusted by Cn in steps of 1 and is transmitted in three frames. Large number of judgments. The variation range of Cn is between Cn(min) and Cn(max). As shown in Figure 2, it is the 0PUK frame format, in which the 1st to 3rd rows of the 16th column are used to place Cbyte bytes to indicate the number of customer data bytes Cn transmitted in a 0TN frame period. A total of 3808 x 4 = 15232 bytes in the payload area, a total of 14 bits of length is required for indication, where Cbyte is allocated 3 bytes of space, which is sufficient to indicate the number of bytes of the client data. As shown in Figure 3, for the OPUk-Χν frame format, each Cbyte is allocated 3 bytes of space, and X Cbyte bytes are transmitted in each frame, and X virtual concatenations are sold (VC0H).

If you need to transfer multiple different Cn, you need to transfer at least 3 identical Cn continuously to change. The value of Cn, transmitting a new Cn. The receiving end makes a large decision on 3 frames to determine the correct Cn value. The definition of Cbyte is shown in Figure 4.

At the transmitting end of the optical network frame, the client data is stored in the data buffer (FIFO), and a Cn value is initialized, indicating that Cn customer data is to be read from F I F0 and placed in the optical network frame for transmission.

If the client clock slows down relative to the system clock, the data in the FIFO will gradually decrease, which will trigger the subtraction operation. The D bits in all Cbyte bytes will be inverted, the Cn value will be decremented by 1, and one less will be read from the FIFO. Bytes of customer data. If the client clock is faster than the system clock, the data in the FIFO will gradually increase, which will trigger the addition operation. The I bit in all Cbyte bytes will be inverted, the Cn value will be increased by 1, and one more will be read from the FIFO. Bytes of customer data.

If a new client signal is detected, the new client flag (NCF) in the Cbyte byte will change from "01" to "10", and the last 22 bits in the Cbyte byte will indicate a new one. Cn value.

In the prior art, the step size is adjusted to 1. The OPUk can provide a frequency offset compensation capability of plus or minus 65 ppm, and the OPUk-Χν can only provide a frequency offset compensation capability of one of the positive and negative 65 ppm X points. Therefore, adjusting with a step size of 1 does not provide the same adjustment capability for OPUk and OPUk-Χν.

Thus, in the prior art, the adjustment step size of Cn is limited to 1, not only the adjustment process is slow, but also can not provide the same adjustment capability for OPUk/OPUk-Xv; if it is necessary to transmit a changed Cn value, at least 4 frames are needed. In order to complete the adjustment, one frame transmission increase/decrease indication, and three frames transmit the changed Cn value. At the same time, it is necessary to cache the change of the amount of customer data during 4 frames, which increases the capacity of the cache.

Summary of the invention

The embodiments of the present invention can provide the same adjustment capability to OPUk and OPUk-Χν, and reliably transmit Cn and support flexible adjustment of Cn. Embodiments of the present invention employ the following technical solutions:

A method for transmitting mapping overhead in an adaptive constant bit rate service, comprising:

Obtaining a change value of the number of customer data bytes received in the current transmission frame period with respect to the reference value;

The above change value is placed into the optical channel payload unit overhead area; Generate an optical network frame and send it.

A method for receiving mapping overhead in an adaptive constant bit rate service, comprising:

Parsing the optical network frame;

Obtaining a change value of the number of customer data bytes in the current frame period relative to the reference value according to the parsing result of the optical network frame;

Obtaining the number of customer data bytes transmitted by the current frame according to the above change value and the above reference value. An apparatus for transmitting mapping overhead in an adaptive constant bit rate service, comprising:

a change value obtaining module, configured to acquire a change value of the number of customer data bytes received by the current transmission frame period relative to the reference value;

And a mapping overhead insertion module, configured to: put the foregoing change value into an optical channel payload unit overhead area; and generate a module, configured to generate an optical network frame and send the same.

An apparatus for receiving mapping overhead in an adaptive constant bit rate service, comprising:

a parsing module, configured to parse an optical network frame;

a change value obtaining module, configured to obtain, according to the parsing result of the optical network frame, a change value of the number of customer data bytes in the current frame period relative to the reference value;

And a quantity obtaining module, configured to obtain, according to the change value and the reference value, the number of customer data bytes transmitted by the current frame.

The embodiment of the present invention solves the problem that the same adjustment capability cannot be provided for OPUk and OPUk-Xv by providing a method for transmitting the change value of the number of bytes of the client data in the 0TN frame of the adaptive constant bit rate (CBR) service. Slow question. By passing multiple customer data byte quantity changes in the 0TN frame, the receiving end makes a large number decision, and the correct number of customer data bytes is obtained, thereby improving the reliability of data transmission. By transmitting the above variation values in the 0TN frame, OPUk and OPUk-Xv are provided with the same adjustment capability, and any adjustment of the number of customer data bytes in a certain range can be completed.

DRAWINGS

1 is a block diagram structure diagram defined in a digital encapsulation technique; 2 is a structural diagram of a frame format for transmitting Cbyte bytes in an optical network frame in the prior art; FIG. 3 is a structural diagram of a frame format for transmitting Cbyte bytes when two or more optical network frames are virtual concatenated in the prior art;

4 is a Cbyte byte structure diagram defined in the prior art;

FIG. 5 is a flowchart of a method for transmitting a mapping overhead according to Embodiment 1 of the present invention;

6 is a structural diagram of a Cbyte format defined in Embodiment 1 of the present invention;

FIG. 7 is a flowchart of a method for receiving a mapping overhead according to Embodiment 1 of the present invention;

8 is a block diagram of an apparatus for transmitting mapping overhead according to Embodiment 1 of the present invention;

9 is a block diagram of an apparatus for receiving a mapping overhead according to Embodiment 1 of the present invention;

FIG. 10 is a flowchart of a method for transmitting a mapping overhead according to Embodiment 2 of the present invention;

11 is a structural diagram of a Cbyte format defined in Embodiment 2 of the present invention;

FIG. 12 is a schematic diagram of a Cbyte generation state according to Embodiment 2 of the present invention;

FIG. 13 is a flowchart of a method for receiving a mapping overhead according to Embodiment 2 of the present invention;

14 is a block diagram of an apparatus for transmitting mapping overhead according to Embodiment 2 of the present invention;

FIG. 15 is a block diagram of an apparatus for receiving a mapping overhead according to Embodiment 2 of the present invention.

detailed description

The embodiments of the present invention can provide the same adjustment capability to OPUk and OPUk-Xv, and reliably transmit Cn and support flexible adjustment of Cn. The embodiment of the invention provides a method and device for transmitting and receiving mapping overhead in an adaptive CBR service.

Embodiment 1:

As shown in FIG. 5, the method for sending mapping overhead includes:

501. Obtain a change value of the number of customer data bytes received in the current transmission frame period with respect to a reference value.

The current transmission frame period and the number of customer data bytes received in the previous transmission frame period are obtained, and the number of customer data bytes received in the previous transmission frame period is used as a reference value. Specifically, the client data can be obtained by buffering the received customer data by performing the client clock in a 0TN frame period. Counting, obtaining the current transmission frame period and the number of customer data bytes received in the previous transmission frame period, taking the number of customer data bytes received in the previous transmission frame period as a reference value, and acquiring the current transmission frame period. The change in the number of customer data bytes relative to the reference value. In the 0ΤΝ frame, the client signal is placed in the payload area of the frame. At the transmitting end, the number of bytes Cn of the client data in a 0 frame period can be obtained by counting the client clock in a 0 frame period. In addition to counting by the clock, the current transmission frame period and the number of customer data bytes received in the previous transmission frame period can be obtained according to the change in the number of client data bytes in the cache, and the client received in the previous transmission frame period The number of data bytes is used as a reference value to obtain the change value of the number of customer data bytes received in the current transmission frame period with respect to the reference value.

The number of bytes in the current frame period is compared with the number of bytes in the previous frame period to obtain a change in the number of customer data bytes received in the current transmission frame period relative to the reference value. Record the number of customer data bytes Cn ( cur ) in the current 0TN frame period and the number of customer data bytes Cn ( pre ) in the previous 0TN frame period, according to Δ Cn = Cn ( cur ) - Cn ( pre ) The change value Δ Cn of the number of customer data bytes received in the current frame period relative to the previous frame. In different service types, the variation range of Cn can be calculated according to the system clock of 0TN, the customer clock, and the frequencies of both. If the Δ Cn transmitted in the optical network frame exceeds the variation range of Cn, then Cn ( pre ) Leave it unchanged and set A Cn to 0.

502. Place the change value into an optical channel payload unit overhead area.

In the 0TN frame, the 15th and 16th columns of the 1st to 4th rows are the optical channel payload unit (OPUk) overhead area. The OPUk overhead area includes a PSI-Payload S tructure Ident if ier and a Cbyte byte indicating the number of client signal bytes Cn transmitted in a 0TN frame period. When two or more frames are virtual concatenated, the OPUk also includes a virtual concatenation overhead (VC0H).

In order to transmit the Δ Cn value in the optical network frame, a Cby te format is defined in the embodiment of the present invention. The Cbyte consists of a new client flag, a flip indicator bit, and a message transfer bit. The new client flag is used to indicate whether a new client signal or a normal client signal is transmitted. The flip indicator bit is used to indicate whether the number of client signal bytes transmitted by the current frame is reduced or increased compared to the previous frame. Specifically used to transmit the Δ Cn value, where Δ Cn is the value of the number of customer data bytes received in the current transmission frame period relative to the reference value. As shown in Figure 6. The Cbyte is a space of a total of 24 bits occupying three bytes. The first two bits "CC" are new customer flags indicating a new client signal or a normal client signal; when CC = "01", it indicates that the frame transmits ACn values, and the third to nine bits place flip indication bits. , including an "ADJ" bit, 3 "bits and 3 "D" bits, the last 15 bits carry a Cn change value ACn every 5 bits; when CC = "10", it means that the frame is transmitted The Cn value, the last 22 bits carry a new Cn value.

When CC = "01", if the "ADJ" bit is inverted and "bit flips, then Cn is added. The remaining 15 bits carry a Cn change value ACn every 5 bits, indicating that the number of client signal bytes in the next frame is The number of client signal bytes of the current frame plus ACn; if the "ADJ" bit is inverted and the "D" bit is inverted, it is Cn minus operation, and the remaining 15 bits carry a Cn change value ACn every 5 bits, indicating the next frame The number of client signal bytes is the number of client signal bytes for the current frame minus ACn.

When CC = "01", it indicates a new client signal Cn, and the remaining 22 bits carry a Cn value indicating the number of client signal bytes transmitted in the current frame.

After obtaining the change value ACn of the number of client bytes in the current frame period relative to the number of client bytes in the previous frame, it is necessary to generate a corresponding Cbyte byte according to the Cn value and the ACn value, and insert the Cbyte byte into the OPUk overhead. In the Cbyte area.

The rules for generating Cbyte bytes are as follows:

1. When ACn=0, that is, the Cn value of the current frame does not change with respect to the Cn value of the previous frame. At this time, CC is set to "01", and the latter 22 bits are all 0.

2. When ACn>0, that is, the Cn value of the current frame is increased relative to the Cn value of the previous frame, the CC in the Cbyte of the current frame is set to "01", and the ADJ bit and the three I ratios are inverted to indicate that Cn is to be performed. Add operation, the next frame Cn value is the current Cn value plus ACn.

3. When ACn<0, that is, the Cn value of the current frame is reduced relative to the Cn value of the previous frame, the CC in the Cbyte of the current frame is set to "01", and the ADJ bit and the D bit are inverted to indicate that Cn is to be subtracted. The next frame Cn value is the current Cn value minus ACn. 4. If a new Cn value is generated when a new client signal is detected, then CC is set to "10" and the next 22 bits are used to indicate the new Cn value.

5. When the customer signal is abnormal, Cbyte enters the AI S (Alarm Indication S igna l) alarm state to indicate this abnormal condition. If the client signal is received normally, then Cbyte exits the AIS alarm state and generates a Cbyte byte according to the above rules 1 ~ 4.

503. Generate an optical network frame and send it. Since the variation value Δ Cn of Cn is transmitted in the optical network frame, the adjustment step size of Cn is no longer limited to 1, and OPUk and OPUk-Xv have the same adjustment capability.

As shown in FIG. 7, the method for receiving mapping overhead includes:

701. Analyze an optical network frame.

The receiving end parses the optical network frame sent by the sending end.

702. Obtain a change value of the number of client data bytes in the current frame period relative to the reference value according to the parsing result of the optical network frame.

The receiving end parses the optical network frame. If the first two bits in the Cbyte byte CC = "10", then the last 22 bits in the Cbyte byte indicate the Cn value of the current frame.

If the first two bits in the Cbyte byte CC = "01", then the 3rd to 9th bits in the Cbyte byte are the flip indication bits, and the last 15 bits represent an A Cn value every 5 bits.

By relying on this rule, the Cn value or Δ Cn value of the current frame can be derived from the overhead bytes of the optical network frame.

703. Acquire, according to the change value and the reference value, the number of client data bytes transmitted by the current frame.

When the first two bits of the Cbyte byte CC = "01", according to the last 15 bits of the Cbyte, the change value A Cn of the current frame relative to the number of client signal bytes of the previous frame can be obtained, the last transmission frame period The number of customer data bytes received in is the reference value.

If the ADJ bit flip in the Cbyte is detected, more than one I bit of the three I bits is inverted, and if more than one A Cn of the three A Cn transmitted are equal, it indicates that the Cn of the next frame is added, and the next The frame Cn value is the current Cn value plus A Cn. If the Cn value is within the normal range, then A legal Cn value that stores the Cn value. In different service types, the variation range of Cn can be calculated according to the system clock of 0TN, the client clock, and the frequencies of the two. If the Cn calculated according to the A Cn transmitted in the optical network frame is outside the variation range, Then it indicates that the transmitted A Cn has an error, the Cn value is illegal, and the Cn value is no longer stored.

If the ADJ bit flip in the Cbyte is detected, more than one D bit of the three D bits is inverted, and more than one A Cn of the three A Cn transmitted is equal, indicating that the Cn of the next frame is subtracted, and the next The frame Cn value is the current Cn value minus A Cn. If the Cn value is within the normal range, it is a legal Cn value, and the Cn value is stored.

If the Cbyte is detected in the AIS alarm state for 3 consecutive frames, the receiving end also enters the AIS alarm state; if more than 2 frames detect that ΔCn or Cn in the Cby te byte is out of the normal range, then the receiving end enters Cn. Lost state; if CC=10" in Cbyte bytes is detected for more than 2 consecutive frames, then the receiver is judged to enter the Cn lost state; if a single CC = "10" is detected, or CC = "01" and A Cn is normal Within the range, then it is judged that the receiving end receives the normal, receives the Cn value or the ΔCn value, and stores the Cn value.

Through the above process, the receiving end can obtain the Cn value from the received optical network frame, and obtain the byte number value of the client signal transmitted in one optical network frame. Using the Cn value in the next frame of the current frame, the data of the payload area of the optical network frame is restored according to the ∑-algorithm to the client signal data stored in the current frame, and the client signal clock is smoothly recovered, and the client signal is transmitted. If a Cn loss condition occurs, the data and clock are recovered according to the most recently received normal Cn value.

The embodiment of the present invention solves the problem that the same adjustment capability cannot be provided for OPUk and OPUk-Xv, and the adjustment speed is slow, by providing a method for transmitting the change value of the number of bytes of the client data in the 0TN frame of the adaptive CBR service. By transmitting multiple customer data byte number changes in the 0TN frame, the receiving end makes a large number decision, and the correct number of customer data bytes is obtained, thereby improving the reliability of data transmission. By transmitting the above change values in the 0TN frame, the same adjustment capability is provided for OPUk and OPUk-Xv, and any adjustment of the number of customer data bytes in a certain range can be completed.

An embodiment of the present invention provides an apparatus for transmitting a mapping overhead. As shown in FIG. 8, the apparatus for transmitting mapping overhead includes:

The change value obtaining module 801 is configured to obtain a change value of the number of customer data bytes received by the current transmission frame period with respect to the reference value.

The change value obtaining module 801 includes:

The buffer unit 804 is configured to obtain the current transmission frame period and the number of customer data bytes received in the previous transmission frame period, and use the number of customer data bytes received in the previous transmission frame period as a reference value.

The buffer unit 804 can specifically count the received client data, count the client clock in a 0TN frame period, and obtain the current transmission frame period and the number of customer data bytes received in the previous transmission frame period, and transmit the previous one. The number of customer data bytes received in the frame period is used as a reference value.

In the 0TN frame, the client signal is placed in the payload area of the frame. At the transmitting end, by counting the client clock in a 0TN frame period, the number of bytes Cn of the client data in a 0TN frame period can be obtained.

The comparing unit 805 is configured to compare the number of bytes in the current frame period with the number of bytes in the previous frame period to obtain a change value of the number of customer data bytes received in the current transmission frame period with respect to the reference value.

Record the number of customer data bytes Cn (cur) in the current 0TN frame period and the number of customer data bytes Cn (pre) in the previous 0TN frame period, according to ACn= Cn (cur) - Cn (pre) Obtain a change value ACn of the number of customer data bytes in the current frame period relative to the number of client data bytes in the previous frame. In different service types, the variation range of Cn can be calculated according to the system clock of 0TN, the customer clock, and the frequency of both. If the ACn transmitted in the optical network frame exceeds the variation range of Cn, then Cn (pre) remains. No change, set ACn to 0.

The mapping overhead insertion module 802 is configured to place the change value into the optical channel payload unit overhead area. In the 0TN frame, the 15th and 16th columns of the 1st to 4th rows are the optical channel payload unit (OPUk) overhead area. The PPU-Payload Structure Identifier is included in the OPUk overhead area. And a Cbyte byte used to indicate the number of client signal bytes Cn transmitted in a 0TN frame period. When more than two frames are virtual concatenated, the OPUk also includes a virtual concatenation overhead (VC0H).

In order to pass the Δ Cn value in the optical network frame, a Cby t e format is defined in the embodiment of the present invention. The Cbyte consists of a new client flag, a flip indicator bit, and a message transfer bit. The new client flag is used to indicate whether a new client signal or a normal client signal is transmitted. The flip indicator bit is used to indicate whether the number of client signal bytes transmitted by the current frame is reduced or increased compared to the previous frame, and the information transfer bit is used for transmission. Δ Cn value, where Δ Cn is the value of the number of customer data bytes received in the current transmission frame period relative to the reference value. As shown in Figure 6. The Cbyte—occupies a total of three bytes with a total of 24 bits of space. The first two bits "CC" are new customer flags indicating a new client signal or a normal client signal; when CC = "01", it indicates that the frame transmits ACn values, and the third to nine bits place flip indication bits. , including one ADJ "bit, three "I" bits and three "D" bits, the last 15 bits carry a Cn change value ACn every 5 bits; when CC = "10", it indicates the frame transmission It is the Cn value, and the last 22 bits carry a new Cn value.

The rules for generating Cbyte bytes are as follows:

1. When ACn=0, that is, the Cn value of the current frame does not change with respect to the Cn value of the previous frame. At this time, CC is set to "01", and the latter 22 bits are all 0. 2. When ACn>0, that is, the Cn value of the current frame is increased relative to the Cn value of the previous frame, the CC in the Cbyte of the current frame is set to "01", and the ADJ bit and the three I ratios are inverted to indicate that Cn is to be performed. Add operation, the next frame Cn value is the current Cn value plus.

3. When ACn<0, that is, the Cn value of the current frame is reduced relative to the Cn value of the previous frame, the CC in the Cbyte of the current frame is set to "01", and the ADJ bit and the D bit are inverted to indicate that Cn is to be subtracted. The next frame Cn value is the current Cn value minus ACn.

4. If a new Cn value is generated when a new client signal is detected, then CC is set to "10" and the next 22 bits are used to indicate the new Cn value.

5. When the client signal is abnormal, Cbyte enters the AIS alarm state to indicate this abnormal condition. If the client signal is received normally, Cbyte exits the AIS alarm state and generates Cbyte bytes according to the above rules 1 ~ 4.

The generating module 803 is configured to generate an optical network frame and send the same.

As shown in FIG. 9, the apparatus for receiving mapping overhead includes:

The parsing module 901 is configured to parse the optical network frame sent by the sending end.

The change value obtaining module 902 is configured to obtain, according to the parsing result of the optical network frame, a change value of the number of customer data bytes in the current frame period relative to the reference value.

The receiving end parses the received optical network frame. If the first two bits in the Cbyte byte CC = "10", then the last 22 bits in the Cbyte byte indicate the Cn value of the current frame.

If the first two bits in the Cbyte byte CC = "01", then the 3rd to 9th bits in the Cbyte byte are the flip indication bits, and the last 15 bits represent an ACn value every 5 bits.

The quantity obtaining module 903 is configured to obtain the number of customer data bytes transmitted by the current frame according to the change value and the reference value.

The quantity acquisition module 903 includes:

The storage unit 904 is configured to: place the received client received in the last transmission frame period The number of data bytes, which is used as a reference value.

When the first two bits of the Cbyte byte CC = "01", the change value A Cn of the current frame relative to the number of client signal bytes of the previous frame can be obtained according to the last 15 bits of the Cbyte, the last transmission frame period. The number of customer data bytes received in is the reference value.

The calculating unit 905 is configured to subtract/add the change value to the number of customer data bytes received in the previous transmission frame period to obtain the number of customer data bytes transmitted by the current frame.

If the ADJ bit flip in the Cbyte is detected, more than one I bit of the three I bits is inverted, and if more than one A Cn of the three A Cn transmitted are equal, it indicates that the Cn of the next frame is added, and the next The frame Cn value is the current Cn value plus A Cn. If the Cn value is within the normal range, it is a legal Cn value, and the Cn value is stored. In different service types, the variation range of Cn can be calculated according to the system clock of 0TN, the client clock, and the frequencies of the two. If the Cn calculated according to the A Cn transmitted in the optical network frame is outside the variation range, Then it indicates that the transmitted A Cn has an error, the Cn value is illegal, and the Cn value is no longer stored.

Through the above process, the receiving end can obtain the Cn value from the received optical network frame, and obtain the byte quantity value of the client signal transmitted in one optical network frame. Using the Cn value in the next frame of the current frame, the data of the optical network frame payload area is restored according to the ∑-algorithm to the client signal data stored in the current frame. Smoothly restore the customer signal clock and send the customer signal out. If a Cn loss condition occurs, the data and clock are recovered according to the most recently received normal Cn value.

Embodiment 2:

The embodiment of the invention provides a method for transmitting mapping overhead.

As shown in FIG. 10, the method for sending mapping overhead includes:

1001. Acquire a change value of the number of customer data bytes received in the current transmission frame period with respect to a reference value. The steps include:

10011. Obtain a quantity of bytes of the client data in the current 0TN frame period, and obtain a minimum value of the number of customer data bytes received in the transmission frame period according to the client clock and the local clock, and use the minimum value as a reference value.

In this step, the client data can be counted in a frame period, and the number of bytes of the client data in the current 0TN frame period is obtained, and the received frame period is received according to the client clock and the local clock. The minimum value of the number of customer data bytes, which is used as a reference value.

In the 0TN frame, the client signal is placed in the payload area of the frame.

At the transmitting end, the customer clock is recovered from the customer signal via the phase locked loop according to the input customer signal, and the customer data is stored in F I F0. The Cn value acquisition unit calculates the minimum value Cn (min) of Cn based on the customer signal clock and the local system clock, and transmits Cn (min) to the Δ Cn acquisition module with Cn (min) as a reference value.

Because the client signal is asynchronous to the system clock, the amount of data in F I F0 changes. When the number of bytes in F I F0 changes, the Cn value acquisition unit generates different Cn values depending on the number of bytes in the FIFO.

Comparing the number of bytes in the current frame period with the minimum value of the number of bytes, a value of the number of customer data bytes received in the current transmission frame period relative to the reference value is obtained. The Δ Cn acquisition module calculates Δ Cn based on the Cn value obtained by the Cn acquisition unit:

△ Cn = Cn _ Cn (min) Under normal conditions, the Cn value will change within a certain range, which can be generated by the Cn calculation formula corresponding to the service, or can be generated by the configuration. If the value of ACn exceeds the range of variation of Cn, the Cn adjustment is discarded and ACn is set to zero.

1002. The change value is placed into an optical channel payload unit overhead area.

In the 0TN frame, the 15th and 16th columns of the 1st to 4th rows are the optical channel payload unit (OPUk) overhead area. The OPUk overhead area includes a PSI-Payload Structure Identifier and a Cbyte byte indicating the number of client signal bytes Cn transmitted in a 0TN frame period. When two or more frames are virtual concatenated, the OPUk also includes a virtual concatenation overhead (VC0H).

In order to pass the Δ Cn value in the optical network frame, a Cbyte format is defined in the embodiment of the present invention. The Cbyte consists of a new customer logo and information transfer bits. The new client flag is used to indicate whether a new client signal or a normal client signal is transmitted, and the information transfer bit is used to transmit an ACn value, wherein the ACn value is a change value of the number of customer data bytes received in the current transmission frame period relative to the reference value. . As shown in Figure 11, the Cbyte—occupies a total of three bytes of a total of 24 bits of space. The first four bits "CC" are new customer flags that indicate new customer signals or normal customer signals. The CC bit is increased from two bits to four bits with respect to the first embodiment, and the increase of the CC bit is advantageous for enhancing the reliability of the Cbyte byte transmission. The 5th and 6th bits are temporarily reserved. The last 18 bits represent an ACn value every 6 bits.

When CC= "0110", if all the next 20 bits are flipped, it means that this frame is only an indication frame, and the Cn value is not transmitted. The ACn value is transmitted from the next frame, and the Cn value of the next frame still maintains the current Cn. value. When CC = "0110", if all the following bits are not inverted, the 5th and 6th bits are reserved, and the remaining 18 bits carry a Cn change value ACn every 6 bits, and the indication range of △ Cn is 0. ~63, The Cn value of the next frame is the current Cn (min) plus ACn. When CC = "1001", it means that the frame transmits a new Cn minimum value Cn ( min ), and the remaining 20 bits are all used to represent the Cn ( min ).

The calculated ACn is placed in Cbyte bytes for transmission, and three identical ACn values are transmitted in one frame. The receiving end can make a large number decision to determine the correct ACn value.

The Cbyte generation state machine can be used to determine the current Cn minimum value Cn (min). Determine the new service, or send the change value ACn of Cn to adjust the determined service. The Cbyte generation state opportunity generates the corresponding Cbyte byte and places it into the optical network frame for transmission.

As shown in Figure 12, it is a schematic diagram of the Cbyte generation state. The Cbyte generation state machine determines whether a new client signal is present or not based on the Cn minimum value fed by the Cn acquisition unit. If it is detected that the minimum value of Cn changes, then the service changes, new services appear, the Cbyte generation state machine is in the new client signal (NCF) state, and the Cn minimum value Cn (min) is placed in the generated Cbyte byte. The new customer flag CC = "1001", the last 20 bits of the Cbyte carry the new Cn minimum Cn(min). In order to ensure the correct transmission of the Cn minimum value Cn ( min ), it is necessary to transmit multiple identical Cn ( min ).

If it is detected that the minimum value of Cn has not changed, the Cbyte generation state machine jumps to the control (CTRL) state, and the transmission control frame indicates that the change value ACn of Cn is transmitted from the next frame. At this point, the new customer flag CC= "0110", the next 20 bits are all flipped.

After the control frame is transmitted, if the client signal is normal and no new client signal is generated, the Cbyte generation state machine enters the adjustment (ADJ) state and starts transmitting the change value Δ Cn of Cn. In the Cn adjustment frame, CC = "0110", the last 18 bits carry three identical ACn values, and each ACn value occupies 6 bits.

If the customer signal reception is abnormal, the Cbyte generation state machine enters the alarm (AIS) state, indicating an abnormal condition.

After generating the corresponding Cbyte byte, the Cbyte byte is inserted into the Cbyte area of the 0PUK overhead. In the next frame of the control frame, the control signal is read based on the Cn minimum value Cn (min) transmitted in the control frame, and Cn (min) customer data is read. In the next frame of the adjustment frame, the control signal is read according to the Cn change value ACn transmitted in the adjustment frame, and ACn customer data is read. The read client data is mapped to the payload area in the 0TN frame.

1003. Generate an optical network frame and send it.

As shown in FIG. 13, the method for receiving mapping overhead includes:

1301. Analyze an optical network frame.

The receiving end parses the optical network frame sent by the sending end. 1302: Acquire, according to the parsing result of the optical network frame, a change value of the number of customer data bytes in the current frame period relative to the reference value.

The receiving end parses the optical network frame. If CC = "1001" in the Cbyte byte of the received optical network frame, it is determined that the new service indicates Cbyte, and the last 20 bits carries the Cn minimum value Cn (min). If consecutive multiple frames receive the same Cn (min) and the value of Cn (min) is within the normal range, then Cn = Cn (min). Future business will be adjusted based on the Cn (min) until new business emerges.

If CC= "0110" in the received Cbyte byte, and the majority of the last 20 bits are flipped, then the frame is judged to be a control frame, indicating that ACn is carried in the next frame, and the next frame in the current frame The number of bytes in the payload area is still Cn (min).

After receiving the control frame, the adjustment frame is received, CC = "0110", from which the change value ACn of Cn can be obtained, where Cn (min) is used as the reference value.

1303. Obtain, according to the change value and the reference value, a quantity of client data bytes transmitted by the current frame.

When CC = "1001", the last 20 bits carry the Cn minimum value Cn (min). If consecutive multiframes receive the same Cn (min) and the value of Cn (min) is within the normal range, then Cn = Cn ( min ).

When CC = "0110", and most of the last 20 bits are flipped, then the frame is judged to be a control frame, indicating that ACn is carried in the next frame, and the word of the payload area is represented in the next frame of the current frame. The number of sections is still Cn (min).

After receiving the control frame, the adjustment frame is received, CC = "0110", from which the change value ACn of Cn can be obtained. By using a large number decision to determine a correct ACn value, the ACn value is used to calculate the current Cn value:

Cn = Cn ( min ) +△ Cn

If the last obtained Cn value is within the normal range, then it indicates that the Cn value is correct, and the Cn value is stored. The customer data and the client clock are recovered using the Cn value in the next frame of the current frame. The data of the 0PUK payload area is restored according to the ∑_ algorithm to the client signal data of the Cn value stored in the current frame, and the client clock is smoothly recovered, and the client signal is sent out.

If Cn ( mi n ) or A Cn is lost, the customer data and the customer clock are restored according to the most recently received normal Cn value.

The embodiment of the invention further provides an apparatus for transmitting mapping overhead.

As shown in FIG. 14, the apparatus for transmitting mapping overhead includes a change value acquisition module 1401, a mapping overhead insertion module 1402, and a generation module 1403.

The change value obtaining module 1401 is configured to obtain a change value of the number of customer data bytes received by the current transmission frame period with respect to the reference value.

The change value acquisition module 1401 includes a cache unit 1404 and a comparison unit 1405.

The buffer unit 1404 is configured to obtain a minimum value of the number of client data bytes received in the current transmission frame period and the number of customer data bytes received in the transmission frame period, and use the minimum value as a reference value.

The buffer unit 1404 can specifically count the received client data, count the client clock in a transmission frame period, and obtain the number of client data bytes received in the current transmission frame period and the client data bytes received in the transmission frame period. The minimum value of the quantity, which is used as the reference value.

In the 0TN frame, the client signal is placed in the payload area of the frame.

At the transmitting end, according to the input customer signal, when the customer is recovered from the customer signal through the phase locked loop Clock, and store customer data in FIFO. The quantity acquisition unit calculates the minimum value Cn (min) of Cn according to the customer signal clock and the local system clock, and transmits Cn (mi n) to the change value acquisition module, and takes Cn (min) as a reference value.

Because the client signal is asynchronous to the system clock, the amount of data in F I F0 changes. When the number of bytes in F I F0 changes, the quantity acquisition unit generates a different Cn depending on the number of bytes in the FIFO. The quantity acquisition unit can also obtain the number of customer data bytes Cn of the current transmission frame period by counting the client clock in one transmission frame period.

The comparing unit 1405 is configured to compare the number of bytes in the current frame period with the minimum value of the number of customer data bytes received in the transmission frame period, to obtain the relative number of customer data bytes received in the current transmission frame period. The value of the change in the reference value.

The change value acquisition module calculates Δ Cn based on the Cn value obtained by the quantity acquisition unit:

△ Cn = Cn _ Cn (min)

In the normal state, the Cn value will change within a certain range, which can be generated by the Cn calculation formula corresponding to the service, or can be generated by the configuration. If the value of A Cn exceeds the range of Cn, the Cn adjustment is discarded and A Cn is set to 0.

The mapping overhead insertion module 1402 is configured to place the change value into the optical channel payload unit overhead area. In the 0TN frame, the 15th and 16th columns of the 1st to 4th rows are the optical channel payload unit (OPUk) overhead area. The overhead area in the OPUk includes a PSI-Payload S tructure Ident if ier and a Cbyte byte indicating the number of client signal bytes Cn transmitted in a 0TN frame period. When two or more frames are virtual concatenated, the OPUk also includes a virtual concatenation overhead (VC0H).

In order to transmit the Δ Cn value in the optical network frame, a Cbyte format is defined in the embodiment of the present invention. The Cbyte consists of a new customer flag and information transfer bits. The new client flag is used to indicate whether a new client signal or a normal client signal is transmitted. The message transfer bit is used to transmit the A Cn value, where the A Cn value is the number of customer data bytes received in the current transmission frame period relative to the reference value. Change value. As shown in FIG. 11, the Cbyte occupies a total of 24 bits of space of three bytes. The first four bits "CC" are new customer flags that indicate new customer signals or normal customer signals. CC bit relative to the embodiment As one bit is increased from two bits to four bits, the increase in CC bits is advantageous for enhancing the reliability of Cbyte byte transmission. The 5th and 6th bits are temporarily reserved. The last 18 bits represent an ACn value every 6 bits.

When CC= "0110", if all the next 20 bits are flipped, it means that this frame is only an indication frame, and the Cn value is not transmitted. The ACn value is transmitted from the next frame, and the Cn value of the next frame still maintains the current Cn. value. When CC = "0110", if all the following bits are not inverted, the 5th and 6th bits are reserved, and the remaining 18 bits carry a Cn change value ACn every 6 bits, and the indication range is 0~63. The Cn value of the next frame is the current (3⁄4( 1^1 ) plus (1. When CC = "1001", it means that the frame transmits a new Cn minimum value Cn (min), and the remaining 20 The bits are all used to represent the Cn (min).

The Cbyte generation state machine can be used to determine whether the current Cn minimum value Cn (min) is used to determine a new service or to send a change value of Cn. ACn adjusts the determined service. The Cbyte generation state opportunity generates the corresponding Cbyte bytes and places them into the optical network frame for transmission.

As shown in Figure 12, it is a schematic diagram of the Cbyte generation state. The Cbyte generation state machine determines whether a new client signal is present or not based on the Cn minimum value fed by the Cn acquisition unit. If it is detected that the minimum value of Cn changes, then the service changes, new services appear, the Cbyte generation state machine is in the new client signal (NCF) state, and the Cn minimum value Cn (min) is placed in the generated Cbyte byte. The new customer flag CC = "1001", the last 20 bits of Cbyte carry the new Cn minimum Cn( min ). In order to ensure the correct transmission of the Cn minimum value Cn ( min ), it is necessary to transmit multiple identical Cn ( min ).

After the control frame is transmitted, if the client signal is normal and no new client signal is generated, the Cbyte generation state machine enters the adjustment (ADJ) state and starts transmitting the change value Δ Cn of Cn. In the Cn adjustment frame, CC = "0110", the last 18 bits carry 3 identical ACn values, each ACn value Take up 6 bits.

The generating module 1403 is configured to generate an optical network frame and send the same.

An embodiment of the present invention further provides an apparatus for receiving a mapping overhead.

As shown in FIG. 15, the apparatus for receiving mapping overhead includes a parsing module 1501, a change value obtaining module 1502, and a quantity obtaining module 1503:

The parsing module 1501 is configured to parse the optical network frame.

Parse the optical network frame sent by the sender.

The change value obtaining module 1502 is configured to obtain, according to the parsing result of the optical network frame, a change value of the number of customer data bytes in the current frame period relative to the reference value.

What is received after the control frame is the adjustment frame, CC = "0110", from which the change value ACn of Cn can be obtained, where Cn (min) is used as the reference value. The quantity obtaining module 1503 is configured to obtain the number of customer data bytes transmitted by the current frame according to the change value and the reference value.

The quantity acquisition module 1503 includes a storage unit 1504 and a calculation unit 1505.

The storage unit 1504 is configured to set a minimum value of the number of customer data bytes received in the acquired transmission frame period, and use the minimum value as a reference value.

The calculating unit 1505 is configured to add the minimum value of the number of customer data bytes received in the transmission frame period to the change value to obtain the number of customer data bytes transmitted by the current frame.

Cn = Cn ( min ) +△ Cn

If the last obtained Cn value is within the normal range, then the Cn value is correct and the Cn value is stored.

The customer data and the client clock are recovered using the Cn value in the next frame of the current frame. The data of the 0PUK payload area is restored according to the ∑_ algorithm to the client signal data of the Cn value stored in the current frame, and the client clock is smoothly recovered to transmit the client signal.

If Cn (min) occurs and ACn is lost, the customer data and the customer clock are restored according to the most recently received normal Cn value.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any person skilled in the art can easily within the technical scope disclosed by the present invention. Any changes or substitutions are contemplated as being within the scope of the invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

Claim

Obtaining a change value of the number of customer data bytes received by the current transmission frame period with respect to the reference value; and placing the change value into the optical channel payload unit overhead area;

Generate an optical network frame and send it.

The method for transmitting a mapping overhead according to claim 1, wherein the obtaining the value of the number of customer data bytes received in the current transmission frame period relative to the reference value comprises:

Obtaining the current transmission frame period and the number of customer data bytes received in the previous transmission frame period, and using the number of customer data bytes received in the previous transmission frame period as a reference value;

The number of bytes in the current transmission frame period is compared with the number of bytes in the previous transmission frame period to obtain a change value of the number of client data bytes transmitted in the current transmission frame period with respect to the reference value.

Obtaining the number of customer data bytes received in the current transmission frame period;

Obtaining a minimum value of the number of customer data bytes received in the transmission frame period according to the customer clock and the local clock, and using the minimum value as a reference value;

The number of bytes in the current transmission frame period is compared with the minimum value to obtain a change value of the number of customer data bytes transmitted in the current transmission frame period with respect to the reference value.

4. A method for receiving mapping overhead in an adaptive constant bit rate service, the method comprising:

Parsing the optical network frame;

Obtaining a change value of the number of client data bytes in the current transmission frame period relative to the reference value according to the parsing result of the optical network frame;

Obtaining a client data byte transmitted by the current transmission frame period according to the change value and the reference value Quantity.

The method for receiving a mapping overhead according to claim 4, wherein the obtaining the number of client data bytes transmitted by the current transmission frame period according to the change value and the reference value comprises: acquiring a previous transmission The number of customer data bytes received in the frame period, the number of bytes is used as a reference value;

The number of customer data bytes transmitted in the current transmission frame period is obtained by subtracting/adding the change value to the number of customer data bytes received in the previous transmission frame period.

The method for receiving a mapping overhead according to claim 4, wherein the obtaining the number of client data bytes transmitted by the current frame according to the change value and the reference value comprises:

Obtain a minimum value of the number of customer data bytes received in the transmission frame period according to the client clock and the local clock, and use the minimum value as a reference value;

The minimum value is added to the change value to obtain the number of customer data bytes transmitted by the current frame.

7. Apparatus for transmitting mapping overhead in an adaptive constant bit rate service, comprising:

And a mapping overhead insertion module, configured to: put the change value into an optical channel payload unit overhead area; and generate a module, configured to generate an optical network frame and send the same.

The apparatus for transmitting a mapping overhead according to claim 7, wherein the change value obtaining means comprises:

a buffer unit, configured to obtain a current transmission frame period and a number of customer data bytes received in a previous transmission frame period, use the number of customer data bytes received in the previous transmission frame period as a reference value, or obtain a current transmission frame. The minimum number of customer data bytes received in the cycle and the minimum number of customer data bytes received during the transmission frame period, and the minimum value is used as a reference value;

a comparing unit, configured to compare the number of bytes in a current transmission frame period with the number of bytes in a previous transmission frame period, or to transmit the number of bytes in a current transmission frame period The minimum value of the number of customer data bytes received during the frame period is compared to obtain a change value of the number of customer data bytes received in the current transmission frame period with respect to the reference value.

9. An apparatus for receiving mapping overhead in an adaptive constant bit rate service, the method comprising:

a parsing module, configured to parse an optical network frame;

a change value obtaining module, configured to obtain, according to a parsing result of the optical network frame, a change value of a quantity of customer data bytes in a current frame period with respect to a reference value;

And a quantity obtaining module, configured to obtain, according to the change value and the reference value, a quantity of customer data bytes transmitted by the current frame.

The apparatus for receiving a mapping overhead according to claim 9, wherein the quantity obtaining module comprises:

a storage unit, configured to place the number of customer data bytes received in the last transmission frame period obtained, use the number of bytes as a reference value, or place the number of customer data bytes received in the obtained transmission frame period The minimum value, which is the reference value;

a calculating unit, configured to subtract/add the value of the number of customer data bytes received in the last transmission frame period to obtain the number of customer data bytes transmitted by the current frame; or receive the received data frame period The minimum value of the number of customer data bytes plus the change value is the number of customer data bytes transmitted by the current frame.