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



At 03:39 PM 2/18/97 -0500, C. Harald Koch wrote:
>In message <199702181014.LAA01115@kom30.ethz.ch>, Germano Caronni writes:
>> 
>> Compression allows for saving a valuable ressource.
>
>Which valuable resource is that? In my books, compression is a time-time
>tradeoff; the amount of time spent compressing v.s. the amount of time spent
>transmitting. As network bandwidths get higher and higher, compression gets
>more and more expensive.

The valuable resource is indeed bandwith. Clearly, to get the gain, you
have to be able to do the compression at a rate which lets you keep the
network pipe full. I would argue that as network bandwidths get higher and
higher, while the cost of compression gets more expensive (in terms of CPU
or dedicated coprocessors), the economic gain of the additional bandwidth
provided gets larger. In today's private T1/E1 leased lines, adding
compression at the PPP level provides anywhere from 2:1 to 4:1 (and some
even claim more) compression, providing substantial dollar savings over an
uncompressed leased line. Note that for these higher speeds, you're
typically talking about a router interface or some other dedicated WAN
interface box.

-Bob