On Wed, 4 Jul 2012, Chin Guok wrote:
Actually the IDCP has a single phase reservation workflow.
I stand corrected.
That is the reason why it explicitly only supports the chain model.
(going off topic here) Mmm... I do not see why that should restrict it to chain model. Sure tree will be somewhat oppertunistic, but as long as one can cancel the connections I do not see thep roblem. Could you eloborate? Anyway, my point was that we should be careful about trading a simpler model for a more complex one in order to gain potentially better fault handling. 2PC has problems as well, the main ones being coordinator failures and added implementation complexity. There is a middleground with oppertunistic methods (e.g., 3PC without the precommit - essentially pre-check + change without any blocking), which provide almost the same functionality but at a much lower implementation cost. It feels a lot like we are using 2PC for the sake of using 2PC. Best regards, Henrik Henrik Thostrup Jensen <htj at nordu.net> Software Developer, NORDUnet