Kitz Forum

Announcements => Site & Forum Discussion => Topic started by: ejs on April 24, 2016, 07:58:20 PM

Title: Feedback for the G.INP Retransmission page
Post by: ejs on April 24, 2016, 07:58:20 PM

http://www.kitz.co.uk/adsl/retransmission.htm

Thinking about how G.INP works in another thread, I also looked at the kitz page on G.INP retransmission. Particularly the bit on "How does G.INP / Retransmission work?"

Quote

3. Original data packets are sent over Bearer Channel 0 as normal.
...
6. Upon receipt of a re-request, the transmitting modem/DSLAM will retrieve the relevant DTU and resend over Bearer Channel 1.

I'm not sure point 6 is correct. The G.998.4 PDF says one latency path carries only overhead data, and the other carries only DTUs. So I think the re-transmitted DTUs get sent over the same channel they were originally sent over.

Title: Re: Feedback for the G.INP Retransmission page
Post by: kitz on April 24, 2016, 08:01:07 PM

Thinking about it you may be correct.
I have to go out now,  nor will I be around tomorrow.

I shall mark this thread as unread, then double check it when I get more time.

Thanks.

Title: Re: Feedback for the G.INP Retransmission page
Post by: WWWombat on April 30, 2016, 09:32:04 PM

I agree with @ejs here. Many (including me) originally thought bearer 1 was used to carry the re-transmissions, but it eventually became clear that it only really had room to carry some of the overhead.

Nowadays, I think that DTU's are only sent over bearer 0, for both original transmission and re-transmission.