FC3 with BEFSR11 Linksys router slow connection

[Bob Chiodini]

On Mon, 2005-03-21 at 08:59 -0600, David Hoffman wrote:
> On Mon, 21 Mar 2005 09:40:24 -0500, Shawn Iverson <shawn at nccsc.k12.in.us> wrote:
> > On Monday, March 21, 2005 7:54 AM Bob Chiodini wrote:
> > >>
> > >
> > >Shawn,
> > >
> > >Have you verified that both the router side and the PC side have the
> > >same speed and duplex settings.  ethtool or mii-tool should help on the
> > >PC side.
> > >
> > >Bob...
> > >
> > >
> > 
> > I think that you are on to something.  That would explain the errors
> > showing up in ifconfig:
> > 
> > RX packets:49595 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:61048 errors:41 dropped:0 overruns:0 carrier:41
> > 
> > My box is 100/Full Duplex.  If the Linksys is 100/Half Duplex, receive
> > packets will arrive without errors, but transmit packets may or may not
> > hit the Linksys at the right time and result in errors, correct?
> > 
> > Next chance I get, I will change the server's link speed and see what
> > happens.  If this is the problem, I would find it to be quite odd
> > because the XP machine that I used for testing is also 100/Full, so why
> > wouldn't have it been affected?  Furthermore, since I also tried putting
> > a 10/100 autosensing switch between the server and the Linksys to check
> > for speed/duplex problems, why would the server still be having trouble?
> > 
> > --
> > 
> 
> Well, first thing to remember is rule number one of networking...
> "You are only as fast as your slowest link".
> 
> If you have a Cable or DSL modem on the other side of the Linksys, you
> know that you are not going to be getting more than 10Mbits of speed
> through them. DSL here in Houston (depending on what level you want to
> pay for) is either 1.5Mbits, or 6.0 Mbits. Cable throughput will vary,
> but usually isn't going to be more than that.
> 
> So is there any reason for your FC3 machine needs a 100Mbit connection
> to the switch?
> 
> Also, the auto-sensing switch might let your FC3 machine do a Full
> Duplex connection to the switch, but if the Linksys is only
> Half-Duplex (while it SHOULD work fine) then having the FC3 at FD
> might not make a difference too.
> 
> Just some things to think about.


Shawn,

Having one end full duplex and the other half, will work some of the
time.  Typically we see about 50% packet loss reported from ping.  Yours
seems much worse.

Your assumption above seems correct.  What do your logs say?  What kind
of interface is it (what driver)?  My autonegotiation experience with an
older Realtek 8139 and a dlink switch were pretty dismal.  I also have
not been successful getting an integrated 3com in a Dell to play nicely
with our Cisco switch.  Usually it comes up half-duplex while the Cisco
is full-duplex.  Forcing it with mii-tool "usually" takes care of it.
At this moment, however; the carrier # is growing with the TX packets,
but everything says it's full-duplex.  This is a rawhide machine.

As to your other question, placing another switch between the server and
the Linksys and getting the same results may indicate a bug in the
driver.

Maybe someone can enlighten us about what the "CARRIER:" number is.  Two
out of three machines here report zero.  The third (noted above)
indicates a number in the same magnitude as TX packets number.

Bob...