Kitz Forum

Broadband Related => Broadband Technology => Topic started by: Weaver on April 18, 2022, 07:24:40 AM

Title: PTM explained
Post by: Weaver on April 18, 2022, 07:24:40 AM

I’ve been looking for a well-written, understandable document about PTM framing as in VDSL2. (Also, iirc in theory possible in G.992.3/G.992.5, but in practice only seen in G.993.2 (VDSL2)). Something that even stupid people such as me can read. `anyone have any tips ?

Title: Re: PTM explained
Post by: burakkucat on April 18, 2022, 06:23:49 PM

I wonder if the "Ethernet in the First Mile (http://www.ethernetinthefirstmile.com/articles/WTC2002.pdf)" paper [1] might be worth a read?

[1] "Ethernet in the First Mile: an opportunity for xDSL?", Michaël Beck, et al, Alcatel Research & Innovation.

Title: Re: PTM explained
Post by: Weaver on April 18, 2022, 07:05:43 PM

Perfect. I found that ages ago, then `i lost it. `thank you very much!

Title: Re: PTM explained
Post by: burakkucat on April 18, 2022, 07:08:50 PM

The ITU-T G.993.1 Recommendation, Annex H, might also be worth a look. (It covers PTM-TC.)

Title: Re: PTM explained
Post by: burakkucat on April 19, 2022, 03:47:34 PM

I've now read through ITU-T G.993.1, Annex H, and am none the wiser . . .  ???  :(

Title: Re: PTM explained
Post by: Weaver on April 19, 2022, 04:15:34 PM

I was disappointed to only find a description of HDLC. I thought there was a much better, more modern and sophisticated encapsulated technique-63/64 or was it 64/65 byte ? Since HDLC can in pathological circumstances have a bloat expansion factor of 200% iirc this is not sane and more modern techniques fix this. Is this correct?

Title: Re: PTM explained
Post by: burakkucat on April 19, 2022, 04:52:06 PM

There are very few locations that provide details about PTM.

Most of those I found, searching using the string "Packet Transfer Mode", start by describing ATM in quite great detail and then, finally, mention PTM towards the end of the description.  :(