Hi, I've submitted an I-D for the out-of-band protocol I mentioned on the openafs-devel list a few weeks ago:
https://datatracker.ietf.org/doc/draft-deason-afs3-oob/ http://tools.ietf.org/html/draft-deason-afs3-oob-00 That draft is intended to represent the protocol that was actually used for the experimental/prototype implementation that is being used at one site. I am not sure if that is the protocol we want to agree on / standardize and use, though, due to a couple of shortcomings. One is that the OOB address negotation information (section 5.1 union AFSOOB_Challenge) is transmitted for every OOB transfer, which may be noticeably inefficient. Ideally I think we would advertize/negotiate this information separately, but this increases the complexity of the protocol. It will be annoying if we have to maintain yet another piece of per-server information that needs appropriate caching and invalidation, etc. The protocol as described requires a full RTT delay before the OOB connection can be made because of this (since we need to wait for the address info). But, this does simplify some error handling and other parts of the implementation, since if we get an Rx abort, we'll get it before we need to make the OOB connection. But we could still enforce this delay while still keeping the addressing information in separate RPCs, but then I would wonder what the benefit is; we might as well send the addressing info every time. The other limitation is that the "versioning" with the unions isn't very useful for future-proofing, since they're not extended unions. We could just change this to use extended unions and maybe use the standrd address types that will someday exist. With the current protocol I was just trying to keep the size down for the address info, so I could decode using xdrmem in the kernel with stack-allocated memory. But that's probably more of a hindrance in the long run. -- Andrew Deason [email protected] _______________________________________________ AFS3-standardization mailing list [email protected] http://lists.openafs.org/mailman/listinfo/afs3-standardization
