Re: Handling of IPcomp in IKEv2

[Avram Shacham <shacham@shacham.net>]

Henry,

The only comment: Compression algorithms in IPComp MUST be stateless.

Regards,
avram

> Date: Mon, 9 Dec 2002 12:14:04 -0500 (EST)
> From: Henry Spencer <henry@spsystems.net>
> To: IP Security List <ipsec@lists.tislabs.com>
> Subject: Re: Handling of IPcomp in IKEv2
>
> On Sun, 8 Dec 2002, Avram Shacham wrote:
> > Even with that option available, the vast majority of IPComp
> > implementations use the negotiated CPI (range 256-61439)  rather than the
> > well-known numbers...
>
> Most of the motive for this, I think, is that it's convenient to have a
> local object to hold state for compression -- the compression proper is
> usually stateless, but choice of algorithm, intelligent decision on
> whether to attempt compression, etc. require local state -- and negotiated
> CPIs let you give that state a number (although not very conveniently so,
> since the decompressor picks the CPI but it's the compressor that wants to
> keep state).
>
> I don't think any significant amount of the negotiation is being done to
> permit custom compression algorithms.
>
>                                                           Henry Spencer
>                                                        henry@spsystems.net
>
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