It gives immense pleasure for presenting the first edition of this book to our esteemed readers. Contents of all the chapters have been presented in systematic and illustrative manner so that it becomes easy for even a beginner to understand it. I would like to thank all those who directly or indirectly contributed in making this venture a success. This book describe beginning material and terminology associated with routing protocols and describe the different routing protocols in terms of different aspects such as their convergence time, jitter, and traffic send and receive by using voice and video multimedia shown by graphical implementation using Optimized Network Engineering Tool (OPNET). To find the most appropriate routing protocol which leads the above features among them by providing simulation results using best effort and quality of service methods and also discuss parametric studies for the protocols. Finally, I thank the Almighty to bless me with the opportunities, strength, optimism and support. I thank my parents who have been a constant source of inspiration and encouragement.