I was working with a issue, in which we were observing that the citrix application page is freezing intermittently for 5-10secs and again working without any discosnnections.
On troubleshooting I did nt observe any abnormal latency or packet loss on the GRE tunnel from source vlan till server destiantions.
The citrix traffic flows via a GRE tunnel to remote location then via plain internet flows to a internet facing citrix server behind a firewall.
On analyzing the traffic using Ethereal I have observed huge number of duplicate ACK packets and TCP retransmissions, hence i derived it has some thing to do with packet fragmentations.Hence I modified that TCP MSS size to 1400 from 1412.
Hence I modified the GRE tunnel configs as below
Router#sh run int tu 691
ip address X.X.X.41 255.255.255.252
ip mtu 1500
ip tcp adjust-mss 1400
tunnel source Loopback69
tunnel destination X.X.X.X
Still there is intermittent issue.Can you pls help me to find out where excatly the issue can lie.