Re: ICMP ping effecting network flow?



On Thu, 11 May 2006, in the Usenet newsgroup comp.os.linux.networking, in
article <e40gdr$5l1$1@xxxxxxxxxxxxxxxxxx>, Roy L Butler wrote:

I was told by someone at a systems conference about 10 years ago that if
you ping a server over the Internet while downloading a file from it,
your download will take place quicker. I thought it was bogus then and
still kind of lean towards that. I see no difference from some simple
tests I've tried.

Anecdotal evidence - no observed difference. Why? Because the services
have nothing to do with each other. On the server, the 'ftp' or 'web'
server is an application running at the top of the networking stack. With
most operating systems, 'ping' (ICMP Echo) is a network service that is
part of the networking stack. At the client side, 'ping' is normally
just another application - which if anything is stealing CPU cycles that
could ordinarily be used for something more useful.

But, perhaps there's something to do with a common design of routers and
traffic flows that I just don't get.

As far as the routers are concerned, it's just another packet. An ICMP
packet _MAY_ be processed at a lower priority than TCP or UDP, because
ICMP is more used as an error, or diagnostic, while the others are
carrying "useful" data.

The guy who told me got a knowing nod from someone else and neither were
in a position to just be pulling legs.

Why not? Are you the "boss" that they dare not lie to? Or was their boss
present and would not take kindly to such humor?

Were they both wrong and just trying to sound smart? Any (real) info
would be much appreciated. It's tickled the back of my mind for a long
time. :)

Ten years ago - to late to do anything. The right thing to do AT THE TIME
would have been to ask them to explain why they felt this to be true.

Old guy
.



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