3560s, 1gb network connection slower than 100 mbit

[lengoo]

Hi all,
We have Cisco 3560s and generally they work fine. However, what we've found is that when the workstations connection through it are running at 1 gbit speeds, the internet connection is very choppy and can take some time to download stuff. However, 100 mbit connected workstations don't have this problem.
To give an example, 100 mbit took 5 second to download a particular file and for 1 gbit (same file), it took about a minute!!!
I think this is because the firewall is connected at 100 mbit to the switch and the 100mbit machine obviously are running at same speeds. however, with 1 gbit machine, there is a speed mismatch.
How do I fix this? It only seems to affect Internet users, file to file copy for 1 gbit and 100 mbit work as expected (1 gbit is 10x faster than 100 mbit as expected)

Thanks!!

 

[jdeisenm]

Have you looked on the 3560 at the "show interface g0/x" output for the slow device?

Are there any errors?
What is are the speed and duplex settings on the switch port?
What kind of driver is on the client PC?
I've had to reset some Intel Pro 1000 back to auto negotiate.

 

[kcbell]

DO a show interface counter error to see what kind of errors associated with the port.

I would change the speed and duplex to auto and what is negotiated.

KCBell

 

[ADB100]

Do you have QoS enabled? In my experience the 3560 & 3750 begin to drop TCP traffic with WRED far to aggressively when the queue thresholds are reached. Cisco have addressed this is IOS releases 12.2(25)SEE1 and above, however the documentation has still not been updated.

I use the following queue-set thresholds:

mls qos queue-set output 1 threshold 1 800 800 50 3200
mls qos queue-set output 1 threshold 2 560 640 100 800
mls qos queue-set output 1 threshold 3 800 800 50 3200
mls qos queue-set output 1 threshold 4 320 800 100 800

The 1st value is drop threshold 1, the 2nd is drop threshold 2, the 3rd is the reserved bandwidth and the 4th is the maximum bandwidth. They are all specified as percentages, which might seem quite high (except the reserved value), however in previous IOS releases they were 8-times less - i.e.

mls qos queue-set output 1 threshold 1 100 100 50 400

Obviously if any of your interfaces are using queue-set 2 instead of the default queue-set 1 you need to modify that as well.

HTH

Andy

 

[lengoo]

HI All,
It affects all machines connected at 1 gbit.. I have no QOS installed.
Do you think it could be Flow control since data expectation from these machines would be at 1 gbit.. however, our connection to the firewall is 100 mbit and we have a 10 mbit pipe to the Internet.
Regards