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New Member

Samba Filetransfer Slow after enable of MLS QOS

Hi all

At the moment we are implementing VOIP (Alcatel) in our company. Since I activated globally on the switches ?MLS QOS? Samba Filetransfer is very slow. All other applications are running with same speed as before (Filetransfer from Windows, Ftp from Unix)

Throughput from Samba:

With MLS QOS enabled about 790 kbytes

With MLS QOS disabled about 9700 kybtes

I have Cisco 6506 (Version 12.2(18)SXF) and 3560 (Version 12.2(25)SEB4) and HP-UX 11.11. and 11.23 running




Re: Samba Filetransfer Slow after enable of MLS QOS

Try upgrading your 3560s to a later IOS, e.g. 12.2(25)SEE1 as you may be hitting CSCsc96037: "CAT3560 / 3750:QoS causes slow TCP performance"

"Configuring Quality of Service on a CAT3560 or CAT3750 running any IOS can cause certain TCP applications such as NFS to run slower.

This issue will be resolved in Cisco IOS 12.2(25)SEE1."

HTH. Please rate helpful posts!

New Member

Re: Samba Filetransfer Slow after enable of MLS QOS

I have the same problem here with SMB transfers on Windows. It only occurs if copying large amounts of data (>100MB) from a GigabitEthernet port (uplink as example) to a FastEthernet port. It does NOT happen when the data is copied using two GBit or two FastEthernet ports!

transfer rate with mls qos: about 5MByte/s

transfer rate without mls qos: about 10MByte/s

c3750 IOS 12.2(25)SEE2 ip base.

It seems there's the same problem on our c3560.

we tested a similar configuration with Catalyst 3550 and the problem doesn't exist on this platform.

Btw, our QoS configuration is very simple, it just marks the Voice traffic and voice signaling traffic with the correct DSCP and treats everything else as best effort. Voice traffic is mapped to the priority queue, Signalling to another queue and best effort to yet another queue.



New Member

Re: Samba Filetransfer Slow after enable of MLS QOS

I found a solution. But I am not sure if this is a good solution.

Raising the max threshold for the best-effort queue substantially:

mls qos queue-set output 1 threshold 3 100 100 100 800

does the trick for me. The last number raises the maximum threshold of the respective output queue-set.

These parameters are unfortunately not very well documented. The manual states that the maximum value for the maximum-threshold is 400 percent, but the switch accepts values up to 3200. I am not sure if the value is relative to the other queues.

Again, I'm not sur if this has an impact on the quality of service, couldn't get a proof about that.



Re: Samba Filetransfer Slow after enable of MLS QOS

Started a new thread based on the information in this thread. Are there any new developments on this? Did the (mls qos queue-set output 1 threshold 3 100 100 100 800) work out?

New discussion.