Re: [tsvwg] CC/bleaching thoughts for draft-ietf-tsvwg-le-phb-04

[Brian E Carpenter <[e-mail]>]

On 12/04/2018 13:25, Toerless Eckert wrote:
> On Tue, Apr 10, 2018 at 02:59:17PM +0200, Bless, Roland (TM) wrote:
...
 
>>> I) LE CC must ensure that if operating across a congested hop that
>>> is treating LE as BE, LE CC MUST NOT give LE traffic more bandwidth share
>>> than the competing BE traffic, and it SHOULD give it less share.
>>
>>> So i hope thats the uncontentuous part. Here is the interesting part:

Why is this needed when the text already says:

   A packet forwarded with the LE PHB SHOULD have lower precedence than
   packets forwarded with the default PHB, i.e., in the case of
   congestion, LE marked traffic SHOULD be dropped prior to dropping any
   default PHB traffic.  Ideally, LE packets SHOULD be forwarded only if
   no packet with any other PHB is awaiting transmission.

BE and LE PHBs should talk about queueing and dropping behaviour, not about
capacity share, in any case. It's clear that on a congested link, LE
is sacrificed first - peak hour LE throughput might be precisely zero,
which is not acceptable for BE.

     Brian