JP5322029B2 - Virtual concatenation SQ processing method, transmission apparatus and transmission system thereof - Google Patents

Description

  The present invention relates to an SQ processing method for virtual concatenation, its transmission apparatus and transmission system, and more particularly to an SQ processing method for virtual concatenation in SDH / SONET transmission using multi-frames in H4 byte format, its transmission apparatus and transmission system. About.

  The demand for higher speed data communication services and QoS (Quality of Service) has been increasing as communication network infrastructure has become more broadband in response to the recent increase in Internet demand. One of the multiplex transmission systems satisfying this is SDH (Synchronous Digital Hierarchy) / SONET (Synchronous Optical NETwork). SDH / SONET are defined as international standards in ITU-T Recommendation G.703 and Telcordia Recommendation GR-253-CORE, respectively, and have the advantage of effectively multiplexing not only various high-speed services but also existing low-speed services. . In particular, Ethernet over SDH / SONET technology (EoS) that accommodates Ethernet signals (Ethernet is a registered trademark) is widely used for SDH / SONET signals, and ITU-T's G.707 VCAT (Virtual Concatenation) Newly standardized.

  The advantage of VCAT is that it treats discrete paths as a single virtual concatenation group (VCG) and does not depend on a single VC path, which is a conventional information collection unit for SDH / SONET signals, or contiguous concatenation. The bandwidth can be provided. Examples of single VC paths include VC-4 and VC-3, and examples of contiguous concatenation include VC-4-4c and VC-4-16c. Furthermore, each VC path which is a member of the VCG can independently pass through a plurality of transmission paths having different distances as well as the same transmission path. This is because each VC path forms a multiframe using the H4 byte defined in G.707 of ITU-T, so when the arrival time is different via different transmission paths This is because the phase difference between the VC paths can be detected and the phases can be aligned.

  In Patent Document 1, when a failure in a specific path is detected in the receiving side circuit, only data from the normal path excluding the failed path is multiplexed to restore the data, and in the transmitting side circuit, the failure state of the receiving side circuit is set. There is a description that data is transmitted using a normal path when a failure occurs in a part of a plurality of paths in the virtual concatenation by not assigning data to the failed path.

  In Patent Document 2, a data portion of an STM payload signal including physical channels constituting one or more groups of virtual concatenation is stored in the phase adjustment memory 12 for each physical channel by MFI value, There is a description that the reading of the data portion stored in the phase adjustment memory is started based on reception of the MFI value equal to the MFI value for comparison within a predetermined time limit Tmax by the timer in the physical channel.

JP 2003-188845 A JP 2003-333007 A

  However, as described above, in the VCG, each VC path forms a multiframe using the H4 byte, and the SQ number specified by this is defined as 0 to 255. For this reason, when one VCG is composed of multiple VC-3 groups (or multiple VC-4 groups), the number of members is limited to a maximum of 256 members, and the upper limit of transmission capacity when using VCAT There was a problem that the value was limited to VC-3-256v (or VC-4-256v).

  An object of the present invention is to provide a virtual concatenation SQ processing method, a transmission apparatus, and a transmission system for a virtual concatenation that configures a VCG having 256 members or more by changing the H4 byte format.

The virtual concatenation SQ processing method of the present invention is a virtual concatenation SQ processing method in SDH / SONET transmission using multi-frames in the H4 byte format,
When mapping the packet data to the SDH / SONET signal by virtual concatenation using the H4 byte format, the first SQ is set with the upper bit of the H4 byte of the predetermined frame number of the even-numbered multiframe in the H4 byte format. The second SQ is specified by the upper bit of the H4 byte of the predetermined frame number of the odd-numbered multiframe, and the SQ is specified by a combination of the first SQ and the second SQ.

The transmission apparatus of the present invention is a transmission apparatus that performs SDH / SONET transmission using multiframes in the H4 byte format,
A packet processing unit that encapsulates an input Ethernet signal and outputs packet data;
When mapping the packet data to the SDH / SONET signal by virtual concatenation using the H4 byte format, the first SQ is used in the upper bits of the H4 byte of the predetermined frame number of the even-numbered multiframe in the H4 byte format. An SDH / SONET processing unit that designates the second SQ with the higher order bits of the H4 byte of the predetermined frame number of the odd-numbered multiframe, and designates the SQ by a combination of the first SQ and the second SQ;
It is characterized by having.

  In the present invention, it becomes possible to increase the maximum number of members of the VCG, and it is possible to provide a high quality and large capacity communication service.

It is a block diagram which shows the transmission system containing the transmission apparatus concerning one Embodiment and 1st Example of this invention. It is a figure which shows the multi-frame by the H4 byte format concerning one Embodiment of this invention. It is a figure which shows the multi-frame by a H4 byte format. It is a figure which shows the SDH / SONET signal by the VCAT system using a H4 byte format. It is a figure which shows the multi-frame by the H4 byte format concerning the 2nd Example of this invention. It is a figure which shows the multi-frame by the H4 byte format used when using LCAS. It is a figure which shows the SQ value by the combination of SQ1 and SQ2. It is a figure which shows the multi-frame by the H4 byte format concerning the 3rd Example of this invention.

  In FIG. 1, the relay transmission apparatus 2-1 and the relay transmission apparatus 2-2 have SDH / SONET transmission capability using multiframes in the H4 byte format shown in FIG. In this embodiment, Reserved (“0000”) of 1st Multiframe number 13 in Multiframe number shown in FIG. 2 defined in ITU-T G.707 is newly defined as Sequence indicator SQ, and this is used. . In this embodiment, the SDH / SONET transmission device is equipped with an SQ (Sequence indicator SQ) processing method that can specify a larger number of VCG members than the conventional virtual concatenation (VCAT) technology, enabling faster data transmission. And

  The relay transmission device 2-1 accommodates an Ethernet signal transmitted from the Ethernet device 1-1 in an SDH / SONET signal, and transmits it to the relay transmission device 2-2 through a transmission path. At this time, the SDH / SONET processing unit 23-1 maps the packet data to an SDH / SONET signal by the VCAT method using the H4 byte format shown in FIG. For example, in the case of VC-3 (or VC-4), as shown in Fig. 4, the H4 byte consists of 16 frames and one multiframe, and 256 1st multiframes (16 x 256 = 4096) are 2nd multiframes Configure. Further, SQ indicates a member of the VCG, and each upper 4 bits (each bit 1 to 4 == four bits) of the H4 byte of frame numbers 13, 14 and 15 (13th, 14th and 15th frames) in each 1st multiframe. SQ bits 1 to 4, 5 to 8, and 9 to 12 (12 bits in total) specify one of 4096 numbers. As a result, the maximum value of the VCG configuration member is 4096, and the upper limit value of the transmission capacity is VC-3-4096v (or VC-4-4096v).

  On the other hand, the relay transmission apparatus 2-2 demaps the received SDH / SONET signal by the SDH / SONET processing unit 23-2, and transmits the extracted Ethernet signal to the Ethernet device 1-2.

  In this way, in this embodiment, when a transmission capacity of VC-3-256v (or VC-4-256v) or more is required, the maximum VC-3 can be obtained by performing multiframe processing using a new H4 byte format. Transmission up to -4096v (or VC-4-4096v) is possible.

In this application, H4 byte Reserved (“0000”) of 1st Multiframe number 13 in the multiframe of FIG. 2 defined in ITU-T G.707 is used as the Sequence indicator SQ bit. 2 ^{(8 + N)} SQ values can be specified by expressing SQ by adding N bits to Reserved (“0000”) in the multi-frame, and the maximum transmission capacity at that time is VC It can be increased to -3-2 ^{(8 + N)} (or VC-4-2 ^{(8 + N)} ). As a result, a high-quality, large-capacity communication service can be provided.

Hereinafter, more specific examples will be described.
[First embodiment]
FIG. 1 is a block diagram showing a first embodiment according to the present invention. The two Ethernet devices 1-1 and 1-2 have ports 11-1 and 11-2 for performing a function of transferring a frame defined by IEEE802.3 and an Ethernet interface, respectively. The two relay transmission devices 2-1 and 2-2 have ports 21-1, 21-2, packet processing units 22-1, 22-2 and SDH / SONET processing units 23-1, 23-2, respectively. Accommodates and extracts Ethernet signals for SDH / SONET signals.

  In FIG. 1, in the virtual concatenation transmission system according to the present embodiment, the port 11 of the Ethernet device 1-1 and the port 21-1 of the relay transmission device 2-1 are connected via a cable. Similarly, the port 11-2 of the Ethernet device 1-2 and the port 21-2 of the relay transmission device 2-2 are connected via a cable. The SDH / SONET processing unit 23-1 of the relay transmission device 2-1 and the SDH / SONET processing unit 23-2 of the relay transmission device 2-2 are connected through a transmission path. VCG31 means a group of VC paths configured by a plurality of VC-3 sets (or a plurality of VC-4 sets) by VCAT technology.

  Further, although not shown, each Ethernet device 1-1 and 1-2 is connected to other devices that transmit and receive Ethernet signals. The Ethernet device 1-1 transmits a signal to be transmitted to the Ethernet device 1-2 (and its subordinates) among the Ethernet signals received from other devices connected to the own device to the relay transmission device 2-1. Conversely, the Ethernet device 1-1 transmits the Ethernet signal transmitted from the Ethernet device 1-2 (and its subordinates) received from the relay transmission device 2-1 to the corresponding other device connected to the own device. Send. The operation of the Ethernet device 1-2 is exactly the same, and the codes of the Ethernet devices 1-1 and 1-2 and the relay transmission apparatuses 2-1 and 2-2 may be replaced with each other.

  The relay transmission device 2-1 accommodates the Ethernet signal received from the Ethernet device 1-1 in an SDH / SONET signal and transmits it to the relay transmission device 2-2 through the transmission path. On the contrary, the relay transmission device 2-1 extracts the Ethernet signal from the SDH / SONET signal received from the relay transmission device 2-2 through the transmission path, and transmits the Ethernet signal to the Ethernet device 1-1. The operation of the relay transmission apparatus 2-2 is exactly the same, and the codes of the Ethernet devices 1-1 and 1-2 and the relay transmission apparatuses 2-1 and 2-2 may be read from each other.

  The packet processing units 22-1 and 22-2 of the relay transmission devices 2-1 and 2-2 are input from the Ethernet devices 1-1 and 1-2 connected through the ports 21-1 and 21-2. The Ethernet signal is encapsulated using, for example, ITU-T G.7041 GFP (Generic Framing Procedure). According to GFP, various protocols such as Ethernet can be flexibly and efficiently mapped to a transmission network such as SDH / SONET. The packet processing units 22-1 and 22-2 transmit the encapsulated signals to the SDH / SONET processing units 23-1 and 23-2. On the other hand, the packet processing units 22-1 and 22-2 decapsulate packet data such as GFP received from the SDH / SONET processing units 23-1 and 23-2, convert them into Ethernet signals, and convert the port 21-1 , 21-2 to the connected Ethernet devices 1-1 and 1-2.

  The SDH / SONET processing units 23-1, 23-2 of each relay transmission device 2-1, 2-2 send the packet data encapsulated in the packet processing units 22-1, 22-2 of its own device to the SDH / SONET signal It is housed in VCG31 composed of At this time, multi-frame alignment is performed using the H4 byte format defined in FIG. SDH / SONET processing units 23-1 and 23-2 are SDH / SONET processing units 23-2 and 23-1 of relay transmission apparatuses 2-2 and 2-1 that face the SDH / SONET signal of VCG31 via a transmission line. Send to. The SDH / SONET processing units 23-1 and 23-2 are also connected to the VC paths constituting the VCG 31 received from the SDH / SONET processing units 23-2 and 23-1 of the opposite relay transmission apparatuses 2-2 and 2-1. The packet data is taken out and transmitted to the packet processing units 22-1 and 22-2 of its own device. In this way, the virtual concatenation transmission system can transmit the frame from the Ethernet line to the remote Ethernet line using the SDH / SONET network.

  Next, the operation of this embodiment will be described. Here, a case where an Ethernet signal is transmitted from the Ethernet device 1-1 to the Ethernet 1-2 will be described as an example. The operation when transmitting Ethernet from Ethernet device 1-2 to Ethernet device 1-1 is exactly the same, and the codes of Ethernet devices 1-1, 1-2 and relay transmission devices 2-1, 2-2 are mutually connected. You can replace it.

  The Ethernet signal output from the Ethernet device 1-1 is input to the relay transmission device 2-1, and is input from the port 21-1 to the packet processing unit 22-1. The packet signal encapsulated by the packet processing unit 22-1 is input to the SDH / SONET processing unit 23-1, mapped to the STM frame along with the overhead for transferring maintenance operation information, and output to the SDH / SONET line Is done. Here, the insertion of multiframe information, which is one of the overheads for transferring maintenance operation information, will be described.

  The SDH / SONET processing unit 23-1 maps the packet data to an SDH / SONET signal using the H4 byte format shown in FIG. In other words, the lower 4 bits of each H4 byte (bits 5 to 8 = bits 1 to 4 of MFI1) specify one of 16 (0 to 15) frame numbers in one multiframe, and each upper 4 bits of frame numbers 0 and 1 (Each bit1 to 4 = 8 bits of MFI2 bits 1 to 4 and bits 5 to 8 in total) specify one of 256 multiframe numbers. Also, SQ is the upper 4 bits of each H4 byte of frame numbers 13, 14 and 15 (13th, 14th and 15th frames) in each multiframe (each bit1 to 4 = SQ bits 1 to 4, 5 to 8 and Specify any number of 4096 SQs (9 to 12 in total 12 bits).

  On the other hand, the relay transmission apparatus 2-2 inputs the received SDH / SONET signal to the SDH / SONET processing unit 23-2. The H4 byte is read from the Overhead information terminated here, and based on this, the multi-frame and SQ number which are constituent elements of VCG are extracted. Next, phase matching for each VC path is performed using a multiframe, and finally, rearrangement and demapping of payload data of each VC path is performed according to SQ. In this way, packet data (packet data encapsulated with GFP or the like) transmitted on the opposite side is restored. The packet processing unit 22-2 decapsulates the packet data from the SDH / SONET processing unit 23-2, converts it into an Ethernet signal, and transmits it to the Ethernet device 1-2 through the port 21-2.

As described above, in this embodiment, when a VC-3 (or VC-4) path is configured according to a required bandwidth of transmission data, VCG is configured to map transmission data to each frame of each path in the VCG. Then, a new SQ bit is defined in the identification information (H4 byte) for indicating the position and transmission order in the VCG and used. Based on the identification information using this format, mapping of transmission data and demapping of received transmission data are performed for frames of each path. As a result, the upper limit of the VCAT transmission data bandwidth can be set to VC-3-4096v (or VC-4-4096v), which is larger than the conventional VCAT technology recommended by ITU-T G.707. You can build VCG with capacity.
[Second embodiment]
In the first embodiment described above, the SDH / SONET processing units 23-1 and 23-2 use a part of the H4 byte Reserved (“0000”) defined in G.707 of ITU-T as a sequence. Newly used as indicator SQ. In the present embodiment, the upper limit value of the number of VCG constituent members is increased without additionally defining Sequence indicator SQ. The diagram showing the basic configuration and operation of the virtual concatenation transmission system and transmission apparatus of the present embodiment is the same as the configuration of FIG. 1 used in the description of the first embodiment.

  The SDH / SONET processing units 23-1, 23-2 map the packet data to SDH / SONET signals using the H4 byte format shown in FIG. In other words, the lower 4 bits of each H4 byte (bits 5 to 8 = bits 1 to 4 of MFI1) specify one of 16 (0 to 15) frame numbers in one multiframe, and each upper 4 bits of frame numbers 0 and 1 (Each bit1 to 4 = 8 bits of MFI2 bits 1 to 4 and bits 5 to 8 in total) specify one of 256 multiframe numbers. As shown in FIG. 4, VC-3 (or VC-4) combines 16 frames of H4 bytes to form one multiframe, and 256 1st multiframes (4096 frames) form a 2nd multiframe. SQ is specified using two values SQ1 and SQ2 as shown in FIG. First, 256 in the upper 4 bits of each H4 byte of frame numbers 14 and 15 (14th and 15th frames) of even-numbered multiframes (each bit1 to 4 = SQ1 bits 1 to 4, 5 to 8 total 8 bits) Similarly, the upper 4 bits of H4 byte of frame numbers 14 and 15 (14th and 15th frames) of odd-numbered multiframes (each bit1 to 4 = bits 1 to 4, 5 of SQ2) Specify up to 256 SQ2s in 8 bits (~ 8). Then, as shown in FIG. 7, an SQ value is designated by a combination of SQ1 and SQ2. In this way, SQ can take 256 × 256 = 65536 values.

  Incidentally, one of the technologies using VCAT is LCAS (Link Capacity Adjustment Scheme). LCAS is stipulated in ITU-T recommendation G.7042, and it is possible to perform bandwidth increase / decrease by adding / deleting VCG members without interruption. Thereby, flexible band increase / decrease is possible. Fig. 6 shows the H4 byte format used when using LCAS, as defined in ITU-T G.707.

A point of caution when LCAS is applied to the second embodiment is the use of the member status bit in the H4 byte format when LCAS shown in FIG. 6 is used. Conventionally, the member status is defined as 8 bits in one multiframe. Since 1 bit indicates the status of one VCG member, the status of 8 members can be indicated in one multiframe. Since 256 multi-frames are completed, the upper limit of the member status is 8 × 256 = 2048. For this reason, when LCAS is applied to the second embodiment, 65536 SQ values can be specified, but the member status is limited to 2048, so the maximum number of VCG members is 2048. It will be.
[Third embodiment]
In the present embodiment, when LCAS is applied to the second embodiment, a member status bit is newly defined as shown in FIG. When the H4 byte format shown in FIG. 8 is used, the status of 28 VCG members can be transmitted in one multiframe, and the status of VCG members up to 28 × 256 = 7168 can be transmitted. As a result, the maximum number of VCG members is 7168, and the maximum transmission capacity when LCAS is applied to the second embodiment is VC-3-7168v (or VC-4-7168v). In this paper, when LCAS is applied to the second embodiment, all of the reserved status (“0000”) in the H4 byte format shown in FIG. 6 is used as the member status bit, but all the member status bits are necessarily used. There is no need. Although not shown, for example, when N bit member status is added to the H4 byte format of FIG. 6, the status of 8 + N VCG members can be transmitted in one multiframe, and the maximum transmission capacity at that time is VC-3- (8 + N) × 256v (or VC-4- (8 + N) × 256v).

In each of the embodiments described above, Reserved (“0000”) in the conventional H4 byte format is newly defined as a Sequence indicator SQ, and SDH / SONET transmission by multi-frame processing using this is performed to maximize the VCG. For example, it is possible to increase the number of members up to 4096 when 4 bits are added or 2 ^{(8 + N) when} N bits are used, and a high quality, large capacity communication service can be provided.

  The present invention is used for a transmission apparatus and a transmission system having an SDH / SONET transmission capability using a multi-frame in the H4 byte format.

1-1, 1-2 Ethernet equipment
2-1, 2-2 Relay transmission equipment
21-1, 21-2 ports
22-1 and 22-2 Packet processing section
23-1, 23-2 SDH / SONET processing part
31 VCG

Claims (5)

An SQ processing method for virtual concatenation in SDH / SONET transmission using multi-frames in H4 byte format,
When mapping the packet data to the SDH / SONET signal by virtual concatenation using the H4 byte format, the first SQ is set with the upper bit of the H4 byte of the predetermined frame number of the even-numbered multiframe in the H4 byte format. Virtual concatenation characterized by designating, designating a second SQ with an upper bit of the H4 byte of a predetermined frame number of an odd-numbered multiframe, and designating an SQ by a combination of the first SQ and the second SQ SQ processing method. The virtual concatenation SQ processing method according to claim 1 ,
An SQ processing method for virtual concatenation, wherein a reserve bit in the H4 byte format when LCAS is used is added as a status bit. A transmission device that performs SDH / SONET transmission using multiframes in the H4 byte format,
A packet processing unit that encapsulates an input Ethernet signal and outputs packet data;
When mapping the packet data to the SDH / SONET signal by virtual concatenation using the H4 byte format, the first SQ is used in the upper bits of the H4 byte of the predetermined frame number of the even-numbered multiframe in the H4 byte format. An SDH / SONET processing unit that designates the second SQ with the higher order bits of the H4 byte of the predetermined frame number of the odd-numbered multiframe, and designates the SQ by a combination of the first SQ and the second SQ;
A transmission apparatus. The transmission apparatus according to claim 3 , wherein
The SDH / SONET processing unit adds a reserve bit in an H4 byte format when LCAS is used as a status bit. A transmission system comprising the transmission device according to claim 3 and an Ethernet device connected to the transmission device.

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