[LINK] web: The NBN satellite Malcolm Turnbull never wanted prepares for liftoff

[Craig Sanders]

On Wed, Sep 02, 2015 at 03:51:12PM +0930, Glen Turner wrote:
> There's not much uncompressed data by volume on the Internet. Sizeable
> data has already been compressed, often by an algorithm which performs
> better than a general-purpose compression algorithm -- JPEG, GIF, PNG,
> MP3, H.264 video, software packages.
> 
> In-flight compression of the remaining data is getting less and less
> effective. Consider the movement to serve all HTML over TLS. This data
> can't be compressed in-flight, as an encrypted stream should appear
> random.

also, most web-servers can be (and usually are) configured to compress
data on request from the client....and most browsers request compressed
data.

ditto for other kinds of servers - pretty much anything that routinely
transfers bulk quantities of data has the capability, or at leat the
option, of compressing data using compression algorithms like gzip or
lz4

rsync, for example, typically transfers data to/from remote hosts using
ssh, which both compresses and encrypts the data stream.

and, as you say, application-level compression algorithms like these
tend to be better than transit-level compression. and trying to
re-compress already compressed data like pictures or videos usually
just wastes CPU power and sometimes results in negative compression
levels (i.e. the qty of data transferred is greater than if you didn't
recompress it)


craig

-- 
craig sanders <cas at taz.net.au>