Transmission apparatus
View Patent ↗A transmission apparatus is disclosed, which performs positive/negative stuffing with 8-bit/10-bit (8B/10B) codes being kept intact while retaining the normality of 8B/10B codes and the continuity of running disparity (RD) without termination of 8B/10B codes of a plurality of Gigabit Ethernet (GbE) signals received. The apparatus then executes multiplexing and separation after synchronization of the plurality of signals, thereby achieving the “transparent” transport of management information which is contained in the 8B10B codes between user devices.
1. A transmission apparatus for receiving a plurality of encoded user signals and for multiplexing the plurality of encoded user signals to thereby convert these signals into a single multiplexed signal, said apparatus comprising:
a multiplexer performing multiplexing without altering contents including codes of the plurality of encoded user signals, and for sending the resulting multiplexed signal to a transmission path;
a receiver receiving a multiplexed signal from another transmission apparatus via such multiplexed signal's associated transmission path and for separating the multiplexed signal into a plurality of encoded user signals without changing code contents of the multiplexed signal; and
a synchronization processor performing synchronization processing with a block, which consists only of contiguous and adjacent ordered sets /C/, running disparity value is kept noninverted at an start and an end, by insertion or deletion of said block with respect to said code in detecting that an auto-negotiation ordered set is included in the plurality of encoded user signals and that the auto-negotiation ordered set has a data pattern whose running disparity value is kept noninverted at an start and an end, wherein said code is an 8B/10B code and /C/ is defined by the 8B/10B code, and wherein the received signal is an Ethernet signal.
2. The transmission apparatus according to claim 1 , wherein said synchronization processor performing synchronization processing includes an extractor extracting data of 8B/10B code, a checker unit checking whether the extracted data is an ordered set /C/ or /I/ as defined by the 8B/10B code, a writer/reader writing and reading a received user signal into and from a buffer memory without decoding it into the 8B/10B code, a comparator comparing a read address with a write address and for adjusting a next read address position when an address difference between said read address and said write address is in excess of or below a predefined threshold level, and a read address determiner determining, when a need arises to adjust the read address position, the read address position from said address difference and a check result of said received data without loosing continuity of Running Disparity of the 8B/10B code.
3. The transmission apparatus according to claim 1 or 2 , further comprising:
an extractor extracting 8B/10B code data from each of the plurality of received signals made up of 8B/10B codes and for performing, when inserting or deleting data with respect to a stream of received data during execution of stuff synchronization in order to absorb a rate difference between input and output data, stuffing-based synchronization without generating and delivering abusive data violating rules of the 8B/10B code or the continuity thereof.
4. The transmission apparatus according to claim 1 or 2 , further comprising:
an extractor extracting 8B/10B code data from a plurality of received signals made up of 8B/10B codes respectively, and for determining from the extracted data that an identical ordered set is continuously received within a predetermined length of time period; and
a synchronization processor determining, upon insertion or deletion of data with respect to a received data stream during execution of stuff synchronization, data without inversion of a Running Disparity value of 8B/10B code before and after the data to be inserted or deleted, thereby to perform stuff synchronization without damaging every information contained in the 8B/10B code.
5. The transmission apparatus according to claim 1 , wherein said apparatus further comprises:
a converter converting data other than a code containing a comma pattern making up an ordered set into another value without terminating the 8B/10B code with respect to a plurality of received signal configured from 8B/10B codes;
a detector detecting said changed value after separation of a multiplexed transferred signal, and for identifying a port to which the separated data belongs;
an outputter outputting the separated signal to each port based on the identification information; and
a demultiplexer enabling recovery of said changed value to its original value.
6. The transmission apparatus according to claim 1 , wherein said apparatus further comprises:
a multiplexer uniquely determining, with respect to a plurality of received signals made up of 8B/10B codes, an area to be mapped in units of said plurality of received signals with a start of a frame within a fixed length frame being as a reference without terminating the 8B/10B code;
a multiplexer mapping said plurality of signals made up of the 8B/10B codes respectively into this determined area respectively without altering contents of such data;
a demultiplexer receiving a multiplexed signal configured from a fixed length frame with the plurality of 8B/10B code-configured signals being accommodated therein and for detecting a start position of the fixed length frame;
a demultiplexer separating, from the fixed length frame, such plurality of signals respectively from an area with said plurality of 8B/10B code-configured signals being stored therein;
a demultiplexer identifying, based on a relative positional relationship between the start position of the detected fixed length frame and a position at which the separated data have been mapped, a port to which a respective one of the separated data belongs without adding any modification to the plurality of 8B/10B code-configured signals; and
an outputter outputting, based on the identified information, a plurality of separated 8B/10B code-configured signals to respective ports.
7. The transmission apparatus according to claim 6 , wherein the fixed length frame for mapping the plurality of 8B/10B code-configured signals is an optical transport network (OTN) frame.
8. The transmission apparatus according to claim 6 , wherein the fixed length frame for mapping the plurality of 8B/10B code-configured signals is a synchronous digital hierarchy (SDH) frame.
9. The transmission apparatus according to claim 6 , wherein the fixed length frame for mapping the plurality of 8B/10B code-configured signals is a synchronous optical network (SONET) frame.
10. The transmission apparatus according to claim 1 or 2 , wherein the 8B/10B code-configured signal is a signal of 1000BASE-X.
11. The transmission apparatus according to claim 1 , wherein the /C/ contains a data indicative of an operation mode.
12. The transmission apparatus according to claim 1 , wherein the /C/ contains a data indicative of an operation mode which is exchanged between client devices.
13. The transmission apparatus according to claim 1 , wherein the auto-negotiation ordered set is according to the 8B/10B code in IEEE802.3Z.