During the upgrade install, we noticed one of our TLAN and ELAN ports (same XPEC) had created a Loop in our LAN switches. We analyzed and deduced that a cable was reversed on the I/O ports (or so we rationalized). However, last week, after the system had been runnng for two weeks, it happened again, this time out of the blue. Due to an unfortunate issue with the XML file and security domains,our call server had completely collapsed with all gateways incapable of registering. (BTW - more patches coming on that one) Avaya was in pulling logs and we pointed out the switch loops that were occurring and they stated they had not seen it before. So, finding this note was refreshing because there might be a glimmer of thought that our LAN infrastructure is actually configured and working properly. Avaya is trying to recreate in the lab.