[manet] DLEP pause extension

Rick Taylor <rick@tropicalstormsoftware.com> Tue, 20 March 2018 11:42 UTC

From: Rick Taylor <rick@tropicalstormsoftware.com>
To: "manet@ietf.org" <manet@ietf.org>, "lberger@labn.net" <lberger@labn.net>
Thread-Topic: DLEP pause extension
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Date: Tue, 20 Mar 2018 11:41:08 +0000
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Subject: [manet] DLEP pause extension
Precedence: list

Hi Lou,

I'm also having a re-read of the latest pause extension draft.

In general I like it, and think it's almost ready, but I have a couple
of comments:

* Section 3.1 Queue Parameters.  There seems to be a lot of reserved
space to align fields within the data item.  Is this strictly
necessary?  This sounds like an optimization to try to force sub-tlvs
to 8 byte alignment.  Given the DI is coming over TCP, I think this
might be a false optimization.  I know it prevents your diagram from
getting messy, but an arbitrary 28-bits of padding is just a bit weird.
 Given the large chunk of padding, why not make the scale 8 bits to
make implementers life a little easier?

* Section 3.1.  Rather than have the order of items be important
(unlike everywhere else in DLEP), I would prefer to have an explicit
QID in there somewhere.  The same applies to section 3.1.1 Queue
Parameter Sub Data Item.  You already introduce the Queue Index, why
not make it explicit for sanity?

Can I suggest the following DI layout instead, as I think it addresses
both my comments?


The format of the Queue Parameters Data Item could be:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Data Item Type                | Length                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Num Queues  | Scale (8!)    |          Reserved             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Queue Parameter Sub Data Item 1                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                ...                            :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Queue Parameter Sub Data Item n                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The format of the Queue Parameter Sub Data Item could be:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Queue Id     |             Queue Size Qn                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Num DSCPs Qn  |  DS Field Qn  |  DS Field Qn  |  ...          :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                          ...                  |  DS Field Qn  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Cheers,

Rick

[manet] DLEP pause extension Rick Taylor
Re: [manet] DLEP pause extension Lou Berger