Sorry, these are all the sources
Blackman, J. (2005, April 1). Introduction to VOIP Technology. Retrieved from PC Mech: http://www.pcmech.com/article/introduction-to-voip-technology/
Cisco. (2002). How does network convergence support a business strategy? Cisco.
Converged Network Architecture. (n.d.). Retrieved from Protocols.com: http://www.protocols.com/pbook/converged_arch.htm
Limoncell, T. A., Hogan, C. J., & Chalup, S. R. (2007). The Practice of System and Network Administration, Second Edition. Addison-Wesley Professional.
McCabe, J. D. (2007). Network Analysis, Architecture, and Design. Morgan Kaufmann.
Nanos, A. (n.d.). Cost Reduction with a Unified Communications Solution. Microsoft.
Oppenheimer, P. (2012). Top-Down Network Design. Cisco.
Peterson, L. L., & Davie, B. S. (2011). Computer Networks, Fifth Edition: A Systems Approach (The Morgan Kaufmann Series in Networking). Morgan Kaufmann.
Blackman, J. (2005) is the first image source
Oppenheimer, P. (2012). Top-Down Network Design. Cisco. is the one from which the second image was created