i am a network engineer working in a indian s/w firm . recently i am alotted a new project which is based on voip. as this is a very small firm . there is not enough scope for guidance regarding this topic. i can only say the work i am going to do is on network programming . i have to work on sip , rtp and rtcp. so can anybody suggest me what are the things i must read . and in which area i have to master . again i have to design in c and c++ . for that from where i must begin and follow which online resources .