Re: [trill] I-D Action: draft-ietf-trill-over-ip-10.txt

Hi, all,

I'm confused by the TCP encapsulation shown.

If you place TRILL in TCP, you cannot ensure that the TRILL packets are
aligned with the TCP headers. TCP is a bytestream, not message-oriented.

I.e., you need to assume that TRILL packets could be split across TCP
segments or multiple TRILL packets (or portions thereof) could be
contained within a TCP segment. That means you will need a framing
protocol that identifies the start of TRILL packets, and you should
never assume that TRILL packets align with TCP segments.

If you want to try to assume alignment of some sort, you need to discuss
using RDMA, but that's a much bigger can of worms.

Finally, regarding the IANA considerations, IMO the distinction between
TRILL data and TRILL control needs to be indicated in-band, not via
different port numbers. Ports should be requested only for services that
are useful independently (RFC7605).

(frankly, IMO, this system has gone off the rails out of control; you
really ought to treat everything as running over Ethernet using the
TRILL shim and call it a day; the rest should already be sufficiently
handled by Ethernet-in-X encapsulation).

Joe

On 5/31/2017 3:24 PM, Donald Eastlake wrote:
> Hi,
>
> This revision has relatively minor changes to add an optional TCP
> based encapsulation.
>
> Thanks,
> Donald
> ===============================
>  Donald E. Eastlake 3rd   +1-508-333-2270 (cell)
>  155 Beaver Street, Milford, MA 01757 USA
>  d3e3e3@gmail.com <mailto:d3e3e3@gmail.com>
>
> On Wed, May 31, 2017 at 6:16 PM, <internet-drafts@ietf.org
> <mailto:internet-drafts@ietf.org>> wrote:
>
>
>     A New Internet-Draft is available from the on-line Internet-Drafts
>     directories.
>     This draft is a work item of the Transparent Interconnection of
>     Lots of Links of the IETF.
>
>             Title           : TRILL (Transparent Interconnection of
>     Lots of Links) over IP
>             Authors         : Margaret Cullen
>                               Donald Eastlake
>                               Mingui Zhang
>                               Dacheng Zhang
>             Filename        : draft-ietf-trill-over-ip-10.txt
>             Pages           : 41
>             Date            : 2017-05-31
>
>     Abstract:
>        The TRILL (Transparent Interconnection of Lots of Links) protocol
>        supports both point-to-point and multi-access links and is designed
>        so that a variety of link protocols can be used between TRILL
>     switch
>        ports. This document specifies transmission of encapsulated TRILL
>        data and TRILL IS-IS over IP (v4 or v6). so as to use an IP network
>        as a TRILL link in a unified TRILL campus. This document
>     updates RFC
>        7177 and updates RFC 7178.
>
>
>
>     The IETF datatracker status page for this draft is:
>     https://datatracker.ietf.org/doc/draft-ietf-trill-over-ip/
>     <https://datatracker.ietf.org/doc/draft-ietf-trill-over-ip/>
>
>     There are also htmlized versions available at:
>     https://tools.ietf.org/html/draft-ietf-trill-over-ip-10
>     <https://tools.ietf.org/html/draft-ietf-trill-over-ip-10>
>     https://datatracker.ietf.org/doc/html/draft-ietf-trill-over-ip-10
>     <https://datatracker.ietf.org/doc/html/draft-ietf-trill-over-ip-10>
>
>     A diff from the previous version is available at:
>     https://www.ietf.org/rfcdiff?url2=draft-ietf-trill-over-ip-10
>     <https://www.ietf.org/rfcdiff?url2=draft-ietf-trill-over-ip-10>
>
>
>     Please note that it may take a couple of minutes from the time of
>     submission
>     until the htmlized version and diff are available at
>     tools.ietf.org <http://tools.ietf.org>.
>
>     Internet-Drafts are also available by anonymous FTP at:
>     ftp://ftp.ietf.org/internet-drafts/
>     <ftp://ftp.ietf.org/internet-drafts/>
>
>
>
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