Shawn Iverson wrote:
On Monday, March 21, 2005 10:00 AM David Hoffman wrote:
Well, first thing to remember is rule number one of
networking... "You are only as fast as your slowest link".
True, but even the 100baseTX/Full network at work must run as slow as
the dual T1 lines when connecting to the Internet, and those LAN to
Internet links experience no problems.
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?
Possibly.
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.
I performed a series of tests using mii-tool and found something strange
about the Linksys router. If the router is at 100 megabit full or half
(auto-sensing switch in between), regardless of what I set the speed and
duplex to on the Fedora box, I experience the same problems. The
connection is so slow it is nearly worthless, and the same layer 2
errors appear on the TX line. My first suspicion was the switch, but I
have tried several already; when I connect directly to the Linksys, I
still have the same trouble at 100 megabit.
I just discovered that it does work great, however, if I am connected
directly to the Linksys and use the mii-tool to force the connection
speed and duplex to either 10/half or 10/full. The Linksys auto senses
the server's setting and matches it after executing ifdown eth1 && ifup
eth1.
The kicker is that I need a switch between the router and the server
because it is sharing connections with other machines. The switches I
have are auto-sensing, so just as soon as I plug the Linksys into the
switch, it gladly jumps to 100/Full. The router setup page has no way
to force speed and duplex, AFAIK, so it is stuck at 100, leaving me with
the same problem with which I have been originally contending.
What could possibly be screwed up on the Linksys at 100 megabit as to
cause Linux to have so much trouble? Other operating systems, namely
Windows, are not affected. I am approaching a situation where I might
have to find an old 10baseT switch lying around somewhere and use it
instead. On the other hand, it bothers me because the BEFSR11 model is
fairly common, and who knows how many others could run into the same
trouble.
The trick is that autonegotiation is somewhat ill-defined. Windows
has hacks that work around issues such as you are having, but Linux
doesn't.
The solution is to force both ends to 100MbFD and turn off autosense.
We have similar issues with Cisco and Extreme Networks stuff on
occasion. I agree it "should work" but it often doesn't, so we don't
even let them start the discussion.
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- Rick Stevens, Senior Systems Engineer rstevens@xxxxxxxxxxxxxxx -
- VitalStream, Inc. http://www.vitalstream.com -
- -
- Where there's a will, I want to be in it. -
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