Subject: Last Call: IP Payload Compression ...

From: "William Allen Simpson" <[email-masked]>
Date: Mon, 2 Feb 98 20:00:46 GMT

While I'm thinking about it (with regard to IP compression techniques),
I'd like to make a more formal objection to the IP Payload Compression.
The Last Call expired Jan 20, but the new draft (-05) went the exact
opposite of my informal recommendations.

This is a not unreasonable proposal.  The main problem is that the
authors are coming from the IPSec arena, and thus concieved this as
an extension to IPSec, rather than taking a more general approach,
and incorporating both Header and Data compression.

This draft suffers the same myopia that afflicts the Header Compression
with IPv6.  The authors come from a particular background, and have not
envisioned a more general solution.

But the worst problem, in my view, is that the draft does not stand on
its own.  It is dependent on ISAKMP, used by some in the IPSec WG.

In this recent draft, the compression numbers have been removed to the
ISAKMP DOI.  Instead, those numbers should remain in this document, and
the ISAKMP DOI should refer to this document.  All references to ISAKMP
should be removed!

That change would allow this document to be referenced by other WG
efforts, including L2TP, MobileIP, and TLS.

As in the Header Compression draft, terminology and typography could be
cleaned up considerably.  In addition, these folks could learn a bit
about grammar from the non-native English speakers that wrote the Header
Compression draft.  (heavy sigh)

[email-masked]
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---

From: Bob Monsour <[email-masked]>
Date: Mon, 02 Feb 1998 22:57:16 -0800

Bill,

If you have objections or recommendations regarding the IP Payload
Compression working group activities or the draft, I'd suggest copying them
to the wg list. If you've made informal recommendations, it's likely to be
news to those working on the drafts.

>and incorporating both Header and Data compression.

The wg was formed to solve the payload compression problem, not the header
compression problem. As the IESG is attempting to set up working groups to
solve specific problems and this was the scope agreed to with the area
directors involved. See the charter excerpt below.

>its own.  It is dependent on ISAKMP, used by some in the IPSec WG.

As stated in the charter for the wg:

The immediate problem the Working Group will address is the development
of a payload compression protocol for use in conjunction with IPSec.
The working group will develop its specifications to support both IPv4
and IPv6. Although the primary motivation for this WG is the need to
compress packets when IPSec is used, the WG will develop an
architecture that does not preclude its use with other potential
protocols or the absence of IPSec.

The working group will identify and document the mechanisms that allow
two communicating parties to negotiate the use of compression as well
as the compression format to be employed. The Working Group will
consider defining extensions to ISAKMP to support the negotiation of
compression parameters. Use of ISAKMP as the immediate effort shall not
preclude compression in the absence of IPsec.  Alternate negotiation
mechanisms (or even static negotiation), if appropriate, shall be
identified and extended as needed to accommodate the use of payload
compression functionality. Since compression will be negotiated,
existing implementations of IP will interoperate with implementations
that support compression.
[end charter excerpt]

>efforts, including L2TP, MobileIP, and TLS.

Why would TLS need to reference the IP payload specifications when TLS
already includes the capability to negotiate and deploy compression (even
though no algorithms have been defined for its use)? I would expect that in
the absence of IPSec, L2TP and MobileIP would make use of PPP compression.
If IPSec is present to protect those connections, then it would make sense
to use IPPCP.

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