Just to clear up some mis-assumptions I've probably made, can you share additional information regarding your setup? A diagram and any configuration information would be helpful. Good things to know:
1) What devices you are connecting
2) End-to-end latency
3) What protocol you are using to transfer the file
4) Whether or not any other traffic is traversing the link, and if so, what kind and how much (even if it's just "three guys and the Queen playing Farmville")
5) Have you performed any traffic sniffing, and turned up anything odd (unusual number of duplicate ACKs, etc)
6) Distance between the sites
7) Type of fiber used
I Have connected two server 2008 back to back using a NIC of 1G for testing, i copied 25GByte within 6 Mts , now where the matter of buffering and windowing?pls explain???
Okay, and based on your earlier message, there is an 802.1q trunk on the link between the sites, correct? Just wanted to check a couple of other things:
1) I'm assuming that each end station is attached directly to the 6509. Each end station is connected via a 1Gig Ethernet link, correct?
2) Copy/paste of 100G file...this is a Windows copy/paste? (CIFS)
3) Have you confirmed there are no speed/duplex mismatches between any of the devices?
4) What do the interface counters (errors, specifically) show when you view each of the interfaces (both ends of the trunk, and the two end-station interfaces)?
5) How many stations are on the vlan with the two stations in question, and how many vlans are traversing the trunk?
The RTT seems very good (2ms b/w end stations). Quickest thing that pops out in my mind in that case would be port mismatch somewhere (someone's going half-duplex).
Sorry, it's getting difficult to determine remotely based on what you're seeing. JosephDoherty has made great suggestions in his last post, and probably best to focus on checking those out rather than me confusing the issue with additional changes. I'll keep an eye out in case something springs out at me.
Best of luck! -Ed
There is a software named as iperf which can be used for testing bandwidth across the two sites and I think its a freeware. Try it if possible and let us know the results.
@ Edwin.... In any of my rarest of the rare thoughts I could have never imagined that TCP communication could be compared to feeding a baby. It was amazing.. and I m glad that I came across...