> I reviewed draft-ietf-lisp-ddt-08, and my memory is that the only > significant technical question was regarding the "D" bit in Map-Request > messages.
Let me try to make this more clear for you Dale. Thanks for the comment. > Thinking back on it, I believe that the difficulty I was having was with > the explanation of the D bit, not its functionality. In particular, a > DDT server can share a node and a listening port with a Map-Server. Yes, every Map-Server that is part of a child referral from a DDT-node is also a DDT-node. But the DDT-node does not process D=0 Map-Requests but does D=1 Map-Requests by responding with Map-Referral messages. A Map-Server sends Map-Referrals too. And usually a D=0 Map-Request is forwarded by Map-Servers to ETRs so they send Map-Replies. > Both of these servers process Map-Request messages, albeit with > different semantics. Hence the D bit in Map-Request messages is needed > to differentiate which server is to process a given Map-Request message. The reason I explained the above was that the D-bit tells the receiver of a Map-Request what type of message to return regardless of the colocation status of the servers. > My suggestion is that the document define the D bit in this way. Once > that is done, it's obvious for a particular client sending a particular > message whether the D bit should be set. Compare with the current Well depending on what type of device you are referring to as a “client”. Map-Resolvers are part of infrastructure and they are typically the only devices that send D=1 Map-Requests. And they are sending them because they know the Map-Request is going to a DDT node and that they want a Map-Referral as a response. > description, which speaks of the D bit as if it is a classification of > the sender of the Map-Request, which leads to conceptual problems It is not the classification of the sender. > because it requires the document to define the classification and ensure > that all possible clients are properly classified. > > (Ideally, I would advocate that a DDT Map-Request should have a > different type code than a Map-Server Map-Request. But I'm sure that it > is too late to put that fix into existing deployments.) They both have the exact same information, one just solicits a Map-Referral and D=0 doesn’t. Dino _______________________________________________ lisp mailing list lisp@ietf.org https://www.ietf.org/mailman/listinfo/lisp
