  The Level-1 trigger of the CMS experiment at CERN has been designed to select
proton-proton interactions whose final state includes signatures of new physics
in the form of high transverse energy electrons, photons, jets, or high missing
transverse energy. The Level-1 trigger system process data in a pipeline
fashion at a rate of 40 MHz, has a design latency of 128 bunch crossings and an
output rate of 100 KHz. The design of this system is presented with emphasis on
the calorimeter triggers. After a long period of testing and validation of its
performance the Level-1 trigger system has been installed and commissioned at
the CMS experiment at CERN. Cosmic ray data and Monte Carlo events have been
used to compare the actual performance of the trigger with expectations from
off-line emulation models. Results from these studies are presented here. The
limitations of this system to cope with future luminosity upgrades of the LHC,
the Super-LHC, are discussed. The current CMS plan for a new CMS Level-1
trigger system at the Super-LHC is presented. The center point of the new
system is a Level-1 tracking trigger which uses data from a new CMS silicon
tracking detector.
