It seems like Skype’s never going to catch a break this Christmas season. After the outage that caused tens of millions of users to delay their calls and transactions, the free telephony company is facing yet another challenge, as Gradient Enterprises filed a patent infringement lawsuit against them.

Gradient claims to have invented network monitoring and security software that works in a decentralized way, which is essentially how Skype works. Filed last July 2004 and issued this year, U.S. patent no. 7,669,207 “METHOD FOR DETECTING, REPORTING AND RESPONDING TO NETWORK NODE-LEVEL EVENTS AND A SYSTEM THEREOF” is the basis of the suit.

Here’s the description:

A system for detecting, reporting and responding to network node-level occurrences on a network-wide level includes one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in the network.

An event detection system communicates network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents, and a reporting system disseminates from the one or more first mobile agents information describing the detected event to one or more other nodes.

It appears that the downtime has caused the plaintiff to file the lawsuit, as Skype goes on explaining how their network works and what caused the outage.  The hoiday down time and subsequent outage was troubling, and one of the worst instances Skype has faced in nearly 4 years.  This lawsuit merely emphasizes these troubles, as Skype looks to maintain a high profil and move forward independently with its IPO.  Meanwhile, the VoIP industry gets more diverse, with VocalTec launching new products in the midst of Skype’s developments.