Re: Aspera SCP software

[Ed Wilts <ewilts ewilts org>]

On Mon, May 16, 2005 at 05:36:16PM +0100, John Haxby wrote:
> Ed Wilts wrote:
> 
> >It does work well in practise.  The wide-area SAN people use the same
> >concept.  What appears to happen is that the transfers may go over UDP
> >instead of TCP so that you're not trying to ack every packet half-way
> >around the globe but can ack them in bunches.  The end result appears to
> >be a more consistent data flow.  
> > 
> >
> This sounds like windowing to me or am I missing something?  tcp(7) 
> talks about setting the global read and write windows to deal with high 
> bandwidth or high latency connections.   With large windows you don't 
> ack every packet, just every window'th packet don't you? (*)

So how would I go about implementing this for only a specific
destination?  One of the advantages of buying the Aspera solution, of
course, is that you plug it in and it works without too much hacking.
If they're all smoke and mirrors and we can implement something more
open yet supportable with a modern RHEL distribution (we're stuck at
RHEL 3 for now though), so much the better.

> (*) The default window size in DECnet was, years ago, 3 packets.  

Another VMS guy in the ranks!

> I won't embarrass the now defunct company in question by identifying
> them, let's just say that they should've read their manuals.

Feel free to try and embarrass me by telling me how to set this up
properly so that we don't have to buy a 3rd party product.  I'm willing
to learn.
 
        .../Ed

-- 
Ed Wilts, RHCE
Mounds View, MN, USA
mailto:ewilts ewilts org
Member #1, Red Hat Community Ambassador Program