A number of OASIS members and supporters wanted the basic functionality as soon as possible (especially the pull functionality) as they have large user bases in the SME arena that need a lightweight intermittently connectable client to deal with major corporations. The OASIS ebMS Technical Committee decided to deliver the base mandatory functionality as soon as possible and to deliver the optional more complex/advanced/less-used functionality later.

Part 1 is mainly the mandatory functionality that we would expect all major vendor Gateway products to support (although some functionality will be optional on a relationship-by-relationship basis.

Part 2 will have all the more specialised functionality that will probably only be used in major organisations inter-trading e.g. large message handling, messaging routing/forwarding, multiple message bundling and additional transport level support. Although some of the functionality may be applied to the simpler trading environment such as the potential to ask for an individual message as part of a message pull request, this will likely be a special function to address a particular problem and not used as the normal general B2B solution.