On Mon, Dec 22, 2008 at 10:05 AM, David Meyer <[email protected]> wrote: > "A system external"..."is likely". Really? Please explain.
David, What I proposed in TRRP, and I *think* what Robin proposed in Ivip, is that the choice to switch between locators should be driven by a heuristic system external to the protocol itself. The destination system uses this external heuristic to choose its locators, and the source system blindly follows the destination system's instruction. If the path between the source and destination locators is dead, it's up to the destination to figure this out (using the external heuristic system) and alter its locator to one that works. Examples of such a heuristic include: 1. I think my Internet link is bunged up, so I press the "switch locators" button and that alters my map entry. 2. A monitoring system at my network border polls external public probe sites and watches for retransmission in the TCP sessions which pass by it. If the failure rate exceeds the programmed threshold, it decides my Internet link is bunged up and alters my map entry to favor a different locator. 3. A globe-spanning Akamai-like system of testpoints builds a complex map of Internet path states. Combined with some basic information about the state of my connections to my ISPs, it can compute what will usually be a good current locator selection for me. I subscribe to this service. This approach addresses the locator liveness problem by substituting a heuristic for an algorithm. It accepts that while the result will usually be good enough it won't always be perfect and may rarely require intervention. Regards, Bill Herrin -- William D. Herrin ................ [email protected] [email protected] 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004 _______________________________________________ rrg mailing list [email protected] https://www.irtf.org/mailman/listinfo/rrg
