In this talk I will discuss three open questions in the context of multi-source/ multi-terminal network communication via network coding. a) What is the maximum loss in communication rate experienced from removing a single unit capacity edge from a given network? b) What is the maximum loss in rate when insisting on zero error communication as opposed to vanishing decoding error? c) What is the maximum loss in rate when comparing the communication of source information that is ``almost'' independent to that of independent source information? Recent results including intriguing connections between the three questions will be presented. Based on joint work with Michelle Effros. *** Bio: Michael Langberg is an Associate Professor in the Mathematics and Computer Science department at the Open University of Israel. Previously, between 2003 and 2006, he was a postdoctoral scholar in the Computer Science and Electrical Engineering departments at the California Institute of Technology. He received his B.Sc. in mathematics and computer science from Tel-Aviv University in 1996, and his M.Sc. and Ph.D. in computer science from the Weizmann Institute of Science in 1998 and 2003 respectively. Prof. Langberg's research is in the fields of Information Theory and Theoretical Computer Science. His work focuses on the design and analysis of algorithms for combinatorial problems; emphasizing on algorithmic and combinatorial aspects of Information Theory, and on probabilistic methods in combinatorics.