Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 3 Oct 1996 10:08:59 -0400 (EDT)
From:      "Graydon Hoare ()" <admin@multinet.net>
To:        freebsd-isp@freebsd.org
Subject:   Re: FreeBSD as a PPP server
Message-ID:  <Pine.BSF.3.91.961003095315.20647A-100000@house.multinet.net>
In-Reply-To: <199610030808.RAA25042@al.imforei.apana.org.au>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 3 Oct 1996, Peter Childs wrote:

> In article <52uk4s$hms@al.imforei.apana.org.au> you wrote:
> 
> : 2. Is there a real difference between user-mode ppp (iijppp?) and
> :    kernel-mode WRT performance?  I would think it would, especially as you
> :    add more serial ports.
> 
>  I guess so... The userland ppp code is quite slick but i haven't used
>  the kernel land stuff.

I can't argue with the case for uptime, but have you measured the data rate
your clients are capable of using user mode PPP? I have no experience in this
department cause there were already netblazers when I got here, but I'm
hazarding a guess that it will frustrate users to have high-priority system
management tasks taking user-mode runtime away from their traffic.  Doesn't
it make better sense for Syslog, radiusd and getty to be scheduled around the
packet flow, not in with it? I mean, bearing in mind that TCP has pretty
hefty acknowledge cycles, and a "little delay" in the last mile can cut the
effective throughput dramatically... Check it out, Unless the user code is
vastly superior (and here again I profess ignorance. I haven't read it, and
am not smart enough to know one way or another even if I had ;) I'll bet a
carefully configured PPP-server-kernel will give you much nicer results. 

As an aside to super ISP fogies: have you found your way toward optimized 
kernel configurations / driver configurations that could be added to fbsd 
FAQ/handbook under an "ISP" section? Might be nice.

-graydon <admin@multinet.net>





Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.3.91.961003095315.20647A-100000>