Re: [L2tpext] Propagating IP/ECN field when L2TP sits between IP as both L2 payload and PSN

[Bob Briscoe <[e-mail]>]

Ignacio,

On 31/05/17 02:51, Ignacio Goyret wrote:
> Note that things are a bit more complicated in v2 because
> it transports PPP packets, which may include IP packets (or portions
> of PPP packets if using Multilink). I have no issue punting on L2TPv2
> details.
While going back over all the emails in this thread (I am writing up the 
next rev of the draft), the above point raised a couple of questions in 
my mind:

Q1. When you say "portions" of IP packets, does L2TPv2 fragmented these 
as per IP fragmentation so that each 'portion' has an IP header, or are 
they carved up in a PPP-specific way without IP headers on each?

Q2. Does L2TPv3 support PPP in the same way?

Q3. Are there other L2 protocols currently supported by L2TPv3 that can 
carve up IP packets so that there will not be an IP header at the start 
of each payload?

If framing boundaries might be different, I will need to refer to 
section 5.6 of draft-ietf-tsvwg-ecn-encap-guidelines 
<https://tools.ietf.org/html/draft-ietf-tsvwg-ecn-encap-guidelines-08#section-5.6> 
"Reframing and Congestion Markings", but I don't want to add complexity 
if it is not necessary.

Cheers


Bob

-- 
________________________________________________________________
Bob Briscoe                               http://bobbriscoe.net/