Subject: Re: This PMTU thread
To: NetBSD Networking Technical Discussion List <tech-net@netbsd.org>
From: Perry E. Metzger <perry@piermont.com>
List: tech-net
Date: 11/23/1998 14:30:42
I'm violating my own dictum. I'm replying one more time.

Greg A. Woods writes:
> [ On Tue, November 24, 1998 at 02:33:40 (+1100), Robert Elz wrote: ]
> > Subject: Re: This PMTU thread 
> >
> > Then do it, that part of your suggestion is OK, no-one is going to care
> > if your particular NetBSD based router runs like a dog and consumes Mb's of
> > state.
> 
> You haven't been paying attention Robert.  I'm talking about maybe a
> kilobyte per port at most.

Demon Internet in the U.K. was running NetBSD for its routers at the
big exchange point in London for a while as I recall. Lets assume that 
each of those machines was handling fourty or fifty thousand
simultaneous TCP connections transiting through. Thats, what, fifty
megabytes of state? Plus all the CPU for processing each packet? Plus
a giant cache miss for every single packet going by?

Even on modest networks we're talking about a lot of connections.

I imagine that many of UUNets big routers handle hundreds of thousands 
of simultaneous connections passing through them at "the same time".

Perry