Литература

[1] Cisco Voice Over IP. Student Guide -- Cisco Systems Inc, 2003

[2] Cisco IP Telephony. Student Guide. Version 3.3. -- Cisco Systems Inc, 2002

[3] Robert Padjen -- Cisco AVVID and IP Telephony. Design & Implementation -- Syngress Publishing Inc, 2001

[4] Paul J. Fong -- Configuring Cisco Voice Over IP. Second Edition -- Syngress Publishing Inc, 2001

[5] , сайт Cisco Россия