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B/W & issues, general query..

Hi All,

I'm having a really strange issue with a remote site. I can't go into too much detail here, but essentially, we have a 10Mb connection to a remote site over a Layer 3 MPLS VPN (This is managed by our SP)

We have a Cisco 3750 switch at the remote site and only a handful of users. All routing is working correctly, clients on site can happily connect back to our DC's and all citrix sessions etc are working. So in essence, everything is great.

So, the issue is this.

If I copy a large 500MB file from a server in our DC to a machine on the site, I get a great response from the network and the link peaks at about 8Mbps during the transfer. If I start to copy a second file at the same time, the throughput drops to aboput 1.8 - 2Mbps and response times to the network switch on the site jump up to aroun 800 - 1000ms.

To make it stranger, if I copy muktiple small (4 - 10Mb) files at the same time to the site, I get the same results - B/W peaks at 2Mbps and switch onsite slos right down.

So, it seems that performing a single file copy (single flow?) to the site results in great performance, whilst attempting to copy multiple files (different flows?) causes the whole thing to rapidly deteriorate and become unuseable.

On top of this, the whole thing is packaged up into a proprietary VPN tunnel, so as far as the Service Provider can tell, everything is in one tunnel... (We have changed all VPN devices as part of this with no difference and have 10+ other sites with the same setup and no problems)

Now I appreciate that I have not given a huge amount of details here, unfortunately my hands are tied with regards to giving out configs or any further info, but has anyone experienced similar symptoms that may be able to shed any light on what could cause this sort of behaviour?

Any ideas much appreciated!




B/W & issues, general query..


The only thing I can tell you would be to start looking at your switches first. Make sure that all of the connections are negotiated/set at full duplex all throughout. Check for any errors on the link between you and the service provider, the switch and the destination device, and anywhere else that you think you're going through during a transfer. Also to troubleshoot the issue, you may want to remove any policies that you have in between you and the destination if any exist. It sounds like it's constrained to this one site, so I'd start there first.



HTH, John *** Please rate all useful posts ***
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