Duplicate TCP ACKs and Retransmissions seen after upgrading from RHEL 5.5 to RHEL 5.8

Issue

• There was a brief period where TCP data input to us completely stopped for a few seconds and they saw a very high latency (2 - 4.5 seconds) for about 2 minutes." (This is reoccurring and happening intermittently)
• When sending to a system running RHEL 5.5 (2.6.18-194.32.1.el5) the system has no dropped packets and so sent no TCP duplicate ACKs and the sender was not required to retransmit
• When sending to a system running RHEL 5.8 (2.6.18-308.24.1.el5) the system is apparently dropping packets, is sending TCP duplicate ACKs and the sender is required to retransmit