MacPro 3.1 bringing ethernet link down and up

I see those messages sometimes, and my Ethernet is working fine. Is yours?

Any packet losses when you ping the initiators?

The log messages are normal. I get the same messages. The problem lies in the iSCSI system. I suggest you take it up with the vendor.

I don't know. If anyone knows,the SAN vendor would. All I can tell you is that the log messages are not a manifestation of a problem. Maybe if you identify the product, someone else who uses it would be able to tell you something more helpful.

I have a MacPro 3,1 running 10.5.8 Server (Leopard, Not SL) - but a similar sounding problem. Periodically my logs show link being dropped for a few seconds and re-established.

Also, I see about 3%-5% packet loss pinging the machine - and not only at times when the log entries show loss of link. Sometimes pings go unanswered for a second - more often 3-6 seconds; occasionally as much as 25 seconds. This is happening seemingly randomly, every minute or so. I've tried different cables, different switch ports, and both built-in Ethernet ports. Nothing makes a difference.

I'm considering trying a PCIe NIC instead - but was wondering if anyone had seen this problem, and then had it go away with a more recent system upgrade. I'm wondering if taking the pain of installing Lion and rebuilding things is going to fix anything...

en0, 1-Gigabit, Full-duplex, No flow-control,

Also consider enabling flow control.

Also, I see about 3%-5% packet loss pinging the machine

That could be an indication that the physical port is going bad. There should be no measurable losses on a cable under 100 meters length.

What about the cable? Guess worth swapping that out to see if a new cable makes any difference, right?

I agree that it there should be zero packet loss.... all my other hosts have zero, including hosts on the same switch. In my case I tried different cables, different switch ports, both built-in NICs and manually configuring the Ethernet settings with and without flow control. The behaviour doesn't change.

The machine is 3 years old now. So yes, it could be a hardware failure somewhere high enough up the chain to affect both interfaces; but as originally noted by colbruA it seems suspiciously like a low-level driver thing.

In general the machine continues working fine - the network drops are generally brief enough to recover from - so if it was a desktop, you might not notice any problems. However, because I'm using it to serve an Ajax app that gets some brief bursts of intense connection activity, its causing noticeable problems.

I have a PCIe NIC on order; I am hoping that will behave better.

I see this same behaviour on my 3,1 Mac Pro. I have tried cables, switches, ports, manual IP addresses, etc. This was the case with 10.6 AND 10.7, both with fresh installs. I too have a network card on order to overcome this problem. I notice that this happens mostly under extreme load where all 8 cores are working and I am > 50MB/s in or out of the Intel chipset...but I agree everything points to a shoddy driver from Apple on this one.