On Thu, Feb 25, 2010 at 11:34 AM, Tom Keiser <[email protected]> wrote: > On Tue, Feb 23, 2010 at 2:21 AM, Derrick Brashear <[email protected]> wrote: >> Currently, this as well as the 2 types above it are unused and as far >> as I can tell, have been unused since at least afs 3.2. >> >> I'd like to propose the use of this for a peer to share its network >> and packet settings using registered tags and values, notably the >> number of jumbogram fragments a side is prepared to send and receive, >> and the maximum fragment size a side is prepared to receive (the goal >> being large packets) >> >> Before I write up a formal proposal on this I thought I'd float a >> trial balloon. Brief discussion in Edinburgh did not yield any major >> dissent though the proposal lacked any real meat at the time. >> > > Hi Derrick, > > This is intriguing. I have a few questions regarding interop. Given > that this packet type won't get a response from contemporary clients, > is the idea to handle this as an asynchronous negotiation, upgrading > if/when we receive a reply?
Yes. Well, upgrading if we choose to after receiving a reply. > Detecting peer version upgrades with this > scheme seems relatively easy: just resend the params packet > occasionally. However, I'm not entirely sure how to deal with peer > version downgrades. Do you have any ideas? Are we simply > anticipating that all uses of this negotiation scheme will lead to the > peer sending an abort if it downgrades to an earlier rx > implementation? Reduced performance (in cases where packets must be sliced into several buffers), downgrade-by-protocol-negotiation for fields where older limits applied, or aborts. We could codify that those requirements for a downgrade (that it be handled within protocol, still work if more slowly, or abort the connection) and I think it would be reasonable. -- Derrick _______________________________________________ AFS3-standardization mailing list [email protected] http://michigan-openafs-lists.central.org/mailman/listinfo/afs3-standardization
