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Re: TO COMPRESS OR NOT TO CMPRS (please reply)



I have been hesitant to reply to this.

Network Systems presented compression as a feature for an ESP to the IETF
IPSEc group in san jose in 1994. NSC has since productized the proprietary
ESP that includes compression and pays royalties to IBM for this privilege.


We also have numbers on the compression ratios  in real world, long run
time situations, and even clearing the dictionary on every packet, we
average 2:1 compression of data. Even on most small packets, the overhead
of the encapsulationis removed by what compression there is.

(Sarcasm on) Frankly it is in our best interest that the status quo of the
IPSEC group's inability to converge on a compression standard continue
(Sarcasm off).

After igniting this issue, I would also suggest that this is not very easy
issue to resolve. 

Even if there is someone willing to claim that their compression is
unencumbered by patent, are they willing to indemnify you if someone claims
it is not? Our contract with IBM includes a statement that they would
defend us if their code violates someone else's patent. NSC made a
conscious decision to buy because our parent (StorageTek) has deep pockets
and would be deeply vulnerable if a claimed public domain compression
algorithm was not.

I do not know how to handle this.

jim

On Thu, Feb 27, 1997 7:57 PM, Phil Karn <mailto:karn@qualcomm.com> wrote: 
> >I support the use of compression but not in IPsec. It should be done up
> >higher, perhaps the transport level. It's better to compress the stream
> >of data before it's divided into packets than to wait and compress each 
> >packet. I'd rather see 50 packets then 100 smaller ones.
> 
> I feel exactly the same way. I've seen nothing that can beat the
> performance of gzip-style compress up above TCP, e.g., in SSH with the
> -C option.  The fact that gzip is widely distributed GNUware, free of
> patent concerns, is just icing on the cake.
> 
> Phil
> 
>