Subject: Re: getting better throughput from mc0 ethernet interface
To: Bill Studenmund <email@example.com>
From: Russell McManus <firstname.lastname@example.org>
Date: 09/01/2002 20:02:45
Thanks for taking the time to respond. Good idea to test transfers
behind the firewall. Turns out that things are slow there as well.
I will try swapping network cables between the 7300 and the Linksys to
see whether this helps.
 As I mentioned earlier, other machines from behind the firewall
can download at expected speeds.
Bill Studenmund <email@example.com> writes:
> On 1 Sep 2002, Russell McManus wrote:
> > I've got 1.5.2 installed on a powermac 7300. Most things are working
> > beautifully, but I seem to be getting very slow downloads. I suspect
> > that the problem is that the mc0 interface is simplex.
> Nope. That speed is REALLY slow, and something is wrong, but SIMPLEX isn't
> it. Rummaging around in include files (/usr/include/net/if.h to be exact)
> we find:
> #define IFF_SIMPLEX 0x0800 /* can't hear own transmissions */
> That tells the Ethernet system to fake a packet reception when we send a
> packet that we really want to hear (like a broadcast packet).
> > /export/russe 2$ ifconfig mc0
> > ifconfig mc0
> > mc0: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> > address: 00:05:02:ce:73:66
> > media: Ethernet manual
> > inet 192.168.1.3 netmask 0xffffff00 broadcast 192.168.1.255
> > inet6 fe80::205:2ff:fece:7366%mc0 prefixlen 64 scopeid 0x1
> > The machine is behind a Linksys firewall/router. I suspect that the
> > router is not smart enough to do the right thing when a simplex client
> > is attached. Does anyone on the list have any ideas on how to debug
> > the problem?
> Try ftp'ing to the i386 box, and see how that does.
> Also, try checking the cable out. I'm trying to think of the other things
> folks have seen that give such horrid performance.
> Take care,