SerDes method and device having a protocol-agnostic in-band management channel
In-band communication methods and transceivers are provided to enable protocol-agnostic management channel. One illustrative in-band communications method includes: buffering an outbound data stream from a host-side receiver with a data stream buffer, the outbound data stream having a first bit rate; and providing a line-side data stream representing the outbound data stream with an additional word after every N words of the outbound data stream, the line-side data stream having a second bit rate derived from a fill level of the data stream buffer, the additional words including message words and idle words with adjacent message words potentially separated by a predetermined number of idle words.
1. An in-band communications method that comprises, in a local transceiver:
buffering an outbound data stream from a host-side receiver with a data stream buffer, the outbound data stream having a first bit rate; and
providing a line-side data stream having a second bit rate greater than the first bit rate, the line-side data stream representing the outbound data stream with an additional word after every N words of the outbound data stream,
the additional words including message words.
2. The in-band communications method of claim 1 , wherein the second bit rate is derived from a fill level of the data stream buffer.
3. The in-band communications method of claim 1 , wherein the additional words further include a predetermined number of idle words that separate adjacent message words, the predetermined number being greater than zero.
4. The in-band communications method of claim 3 , wherein the idle words include synchronization information.
5. The in-band communications method of claim 3 , further comprising:
storing a packet of message words in a transmit buffer, the packet including a first message word,
wherein the additional words include a message preamble separated from the first message word by the predetermined number of idle words.
6. The in-band communications method of claim 3 , wherein the predetermined number of idle words is greater than one.
7. The in-band communications method of claim 3 , wherein N is 10 4 or greater.
8. The in-band communications method of claim 3 , further comprising, in the local transceiver:
receiving a line-side data stream representing an inbound data stream with an extra word after every N words of the inbound data stream, the extra words including receive message words and idle words, with adjacent receive message words separated by the predetermined number of idle words;
storing the receive message words in a receive buffer; and
providing a host-side data stream representing the inbound data stream without the extra words to a host-side transmitter.
9. The in-band communications method of claim 8 , wherein each of the idle words in the line-side data stream representing the inbound data stream includes a status field indicating whether a remote transceiver is synchronized to the additional words, and wherein each of the idle words in the line-side data stream representing the outbound data stream includes a status field indicating whether the local transceiver is synchronized to the extra words.
10. The in-band communications method of claim 9 , further comprising: using a finite state machine to establish synchronization with the extra words by scanning the line-side data stream for idle words occurring after every N words of the inbound data stream.
11. An in-band communications transceiver comprising:
a data stream buffer configured to buffer an outbound data stream from a host-side receiver, the outbound data stream having a first bit rate;
insertion logic configured to create a line-side data stream representing the outbound data stream by inserting an additional word after every N words of the outbound data stream, the additional words forming a sequence including message words and idle words with adjacent message words separated by a predetermined number of idle words, the predetermined number being greater than zero; and
a line-side transmitter configured to transmit the line-side data stream at a second bit rate that is derived from a fill level of the data stream buffer.
12. The in-band communications transceiver of claim 11 , further comprising:
a transmit buffer configured to store a packet of message words, the packet including a first message word,
wherein the sequence of additional words includes a message preamble separated from the first message word by the predetermined number of idle words.
13. The in-band communications transceiver of claim 11 , wherein the predetermined number of idle words is greater than one.
14. The in-band communications transceiver of claim 11 , wherein N is 10 4 or greater.
15. The in-band communications transceiver of claim 11 further comprising:
a line-side receiver configured to receive a line-side data stream representing an inbound data stream with an extra word after every N words of the inbound data stream, the extra words including receive message words and idle words, with adjacent receive message words separated by the predetermined number of idle words;
extraction logic configured to store the receive message words in a receive buffer and to store the inbound data stream in the data stream buffer; and
a host-side transmitter configured to transmit the inbound data stream without the extra words.
16. The in-band communications transceiver of claim 15 , wherein each of the idle words in the line-side data stream representing the inbound data stream includes a status field indicating whether a remote transceiver is synchronized to the additional words, and wherein each of the idle words in the line-side data stream representing the outbound data stream includes a status field indicating whether the extraction logic is synchronized to the extra words.
17. The in-band communications transceiver of claim 16 , wherein the extraction logic is configured to pause a write clock to the data stream buffer when storing a receive message word in the receive buffer.
18. The in-band communications transceiver of claim 16 , wherein the extraction logic is configured to implement a finite state machine for achieving and maintaining synchronization with the extra words.
19. The in-band communications transceiver of claim 11 , wherein the insertion logic is configured to pause a read clock to the data stream buffer when inserting an additional word.
20. The in-band communications transceiver of claim 11 , wherein the insertion logic is configured to implement a finite state machine for transmitting packets of message words with the predetermined number of idle words between the adjacent message words.