A cursory inspection of many papers on SOA would suggest that the solution required for connectivity in an SOA is an enterprise service bus (ESB). However, this white paper dives deeper into this area, to answer why you need one in an SOA, and what the ESB will do for you. It also addresses whether it is the only thing you need, and if all ESBs are pretty much the same, delivering a standard set of functions for a standardized environment.