Lucent sued Microsoft in March 2006, claiming that technology inthe Xbox 360 used for decoding MPEG-2 files infringes Lucent's patent. Microsoft has now filed a countersuit claiming that two of Lucent's patents are invalid and alleging that Lucent has in fact infringed some Microsoft patents. Microsoft has also voiced its annoyance that Lucent started litigation without engaging in 'meaningful licence negotiations"?. That being said, lawsuits are themselves a form of negotiation.
Lucent has not yet sought an injunction preventing the sale of the XBOX 360, but doing so would certainly raise the stakes in the dispute and apply additional pressure to Microsoft.