Subject: [dtn-interest] Comments on draft-irtf-dtnrg-dgram-clayer-00

From: Elwyn Davies <[email-masked]>
Date: Mon, 14 Jan 2013 19:17:35 +0000

Comments on DGRAM convergence layer draft
(draft-irtf-dtnrg-dgram-clayer-00):

Issues:
s2:
> TCP, a logical choice, guarantees reliability and provides congestion
>    control.  Congestion control is vital to the continued functioning of
>    the Internet, particularly for situations where data will be sent at
>    arbitrarily fast data rates.  Because the Bundle Protocol offers
>    neither congestion control nor reliability, TCP is the RECOMMENDED
>    choice for its encapsulation.  draft-irtf-dtnrg-tcp-clayer
>    [I-D.irtf-dtnrg-tcp-clayer] defines the method for transporting
>    bundles over TCP.
It strikes me that if we are  going to RECOMMEND TCP then this statement
belongs in the TCP document rather than here.  Actually what we doing is
not really RECOMMENDING it but pointing out that you can build a simple
congestion-friendly CL over a TCP transport with particular
characteristics (reliability, in-order delivery, etc) - but if you have
a convergence layer that already has some of the characteristics of TCP
then you don't need to (indeed, should absolutely not) use TCP as
transport as you will get conflict.
 
Editorial/Nits:
s3.1: Probably worth an aside to record that jumbograms are mostly of
the pink elephant variety.

s3.2, para 1: Should include that the recommendation for TCP or LTP
applies to IP based networks only.  There are other networks...
Bluetooth, AX25, etc.

s3.3, last line: s/every LTP segments/every LTP segment/

Regards,
Elwyn