Tom Worthington wrote: > Perhaps someone can answer a question about the current NBN "Interim > Satellite Service" (ISS): Why is compression OFF by default?
It's a reasonable design choice. Probably the one I'd make as it's a can of worms for little benefit. 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. There's the issue of packet loss, an amount of which has to be expected on a satellite link. If each packet stands alone then the effectiveness of compression will be small (it can't "learn" the patterns in the data from previous packets). If compression continues over multiple packets then the loss of a packet means that a number of subsequent packets also can't be decoded and are dropped. This in turn hints to the TCP algorithm that the loss was due to congestion, not media loss. -glen _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
