A popular request we receive is for information on how to calculate message latency. Well, here it is. The handout <a href="http://computernetworks5e.org/blogs/blog/2013/09/03/handout-on-message-latency/latency-supp-2/" rel="attachment wp-att-194">Everything You Ever Wanted to Know About Message Latency</a> should do it. It details the latency model, approximations that are commonly used, and related quantities such as the round-trip time and bandwidth-delay product. Enjoy!