Re: IP compression of entire datagram
Avram Shacham <shacham@cisco.com> Thu, 03 September 1998 00:45 UTC
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Date: Wed, 02 Sep 1998 17:43:26 -0700
To: Michael Giniger <mginiger@tiac.net>
From: Avram Shacham <shacham@cisco.com>
Subject: Re: IP compression of entire datagram
Cc: ipsec@tis.com, ippcp@external.cisco.com
In-Reply-To: <35ED63E7.37BB7B34@tiac.net>
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Michael,
At 03:27 PM 9/2/98 +0000, Michael Giniger wrote:
>Hi
>
>I was reading through the IP compression draft and it appears that the
>draft only intends for IP compression to be performed on the payload
>portion of IP packets. In the case of IP security gateways that
>operate in tunnel mode, is it correct (and standards compliant) to
>perform IP compression on the entire inner IP datagram instead of just
>the payload portion of the inner IP datagram?
Right, IPComp is applied to the IP payload and in the case of a tunnel the payload does include the inner IP header.
Example #1:
[IP2][IP1][TCP][data]
becomes
[IP2][IPCOMP][IP1][TCP][data]
****************** compressed
Example #2:
[IP2]
[ESP spi+replay+iv]
[IPCOMP]
[IP1] ** compressed
[TCP] ** compressed
[data] ** compressed
[ESP padding+next protocol+auth]
This subject was discussed on both ipsec and ippcp mailing lists in the past (recently during 5-98), in case you are looking for more information.
Regards,
avram
- Re: IP compression of entire datagram Avram Shacham