The book you mentioned is priced at $34.34 on Amazon.
I have over 20 years experience on VOIP and SIP and have great insight into the protocol.
We are a software company based in Mumbai specializing on telephony applications - Call Recording, Asterisk and Streaming. We have been working with several US call recording companies for the past more than 10 years. Besides SIP, we have deep understanding on most other VOIP protocols such as H323, UniStim, Skinny and MGCP. For Sip and Skinny we have built our own client that communicates with the Server and implements call recording.
We have been working on telephony for the past 30 years and have progressed from analog telephony to digital to VOIP. Although we do not possess training experience, I am sure our deep experience on telephony would ensure that your employees get a good understanding of the subject.
As we are based in India, the timings would also be suitable for your employees as well as us. Should you require these classes during US hours that would also be possible.
Feel free to let me know if you have any questions.
Thanks
Dave