Have recently upgraded the OS on my 2924XL switches to 12.0(5)WC3b from 12.0(5)XP. Following the upgrade, started receiving the RTD...error message. My topology has two fast ethernet interfaces on the switch connected to two fast ethernet interfaces on a 7500 series router which is running version 12.1(13). The switch interfaces are configured for trunking with ISL encapsulation. They are also fully duplexed. We have been running version 5XP for two years without any problems. What is our problem now and what can we do to correct it. Thanks for your assistance.