latency and possible window size issues across the world

[elmurado1]

Hi,

We've been having problems uploading files across Citrix to an OnBase dbase application. We are in Aus the Citrix farm is in US (CT). Latency is big issue-it is around 260-280ms. Uploading a 2Mb file times out after 4-5minutes. However, we can upload a 2Mb file via ftp to same physical location in US in 40-60s.

Nothing can be done about the latency(AFAIK) also load balancing by our ISP maybe causing the application to have problems reqeuencing packets? Not sure there.

We use SSl to go across Citrix.

Now I've setup a sniff and can see that there are lots of checksum errors(I'm assuming app layer encryption is the cause of that?)

Also, the window sizes advertsied by either end are vastly different-64320 from the client and 8192 from the server. Does this cause the kind of problems we are getting-ie the server is not 'keeping up' with the client? ie the client is ending data that is being buffered by the server but it cannot seem to acknowledge it fast enough-does that sound right?

[kamlesh.sharma]

well windows size can't be change manually. i think from server side you are having excessive CRC.

try using flow based switching nor per-packet so that packet reaching out of sequence problem can be solvedvia this.

Check MTU from server side and client side try to put it 1500 both side and across the network.

what is end-to-end bandwidth in your network.

check for CRC error both side and if any physical layer error you need to c-ordinate with your ISP.

HTH

[elmurado1]

Thanks dude.

I think that the app that we are using is having the issues-as far as we can tell there are no physical problems.

How can I check for CRC errors?

bandwdith on our side to the WAN is 2Mb/2Mb. On this side we are getting excellent throughput-as i said, uploading/downloading files to the same physical location but not via Citrix is fine. It's just across Citrix that we get these issues-specifically for bulk data transfer.

You said to use per-packet or flow based switching-I'm assuming you mean on the server side?

[kamlesh.sharma]

to check CRC you can use show interface command from both the side.

if it is related to citrix than really we have to look at it from server prospective.

if you have only one link of 2 mb than u don't need to be worry about per-destination or per-packet well by default it is per-destination untill and unless you configure anything on router's.