Dennis Hartmann, CCIE No. 15651, CCVP, CCSI, CCNP, CCIP, MCSE, VCP, VCI, Cisco Data Center Network Design Specialist, is a Unified Communications consultant and a lead instructor at Global Knowledge. Dennis was first exposed to CallManager during the CallManager 2.0 time frame when Cisco acquired Selsius. He has worked for various Fortune 500 companies, including AT&T, Sprint, Merrill Lynch, KPMG, and Cabletron Systems.
Read his blog on the NetworkWorld.com Cisco Subnet site.