> -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of Bill > Roome > Sent: Wednesday, October 03, 2012 9:53 PM > To: [email protected] > Subject: [alto] Should we require "numerical" and "ordinal" costs to be > consistent? > > Suppose an ALTO server supports both "numerical" and "ordinal" cost modes > for the same cost type. Should the protocol require that the values for > those two modes to be mutually consistent? > > And if we do want that, how should the requirement be worded? I'm tempted > to say > > "Let num(A,B) and ord(A,B) be the numerical and ordinal costs > for source PID A and destination PID B, respectively. > Then for all PIDs A, B, C and D, > num(A,B) >= num(C,D) implies ord(A,B) >= ord(C,D), > ord(A,B) >= ord(C,D) implies num(A,B) >= num(C,D), > num(A,B) <= num(C,D) implies ord(A,B) <= ord(C,D), > ord(A,B) <= ord(C,D) implies num(A,B) <= num(C,D)." > > Is that sufficient? [Dhruv Dhody>]
For most cost-type (routingcost, hop-count, delay etc) assertion made by Bill above seems correct. Lower the cost ~ better the rank (lower numerical value of rank that is) and vice-versa! But a future cost-type say - (Residual Bandwidth) where it could be opposite: lower the residual bandwidth ~ worse the rank! So I am kind of tempted to leave the protocol as it is without any assertion for any future extensions. What does the WG think? Regards, Dhruv _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
