In einer eMail vom 10.11.2009 08:04:50 Westeuropäische Normalzeit schreibt [email protected]:
the presentation slides are at: http://www.nanog.org/meetings/nanog44/presentations/Wednesday/Zhang_Wed_N44. pdf Quote from these slides: The problem: routing too flat solution: add more hierarchies in addressing & routing Yes, but do hierarchies right. There have been multiple hierarchical proposals which did the hierarchical aggregation in the wrong way. What it takes is a "sliding hierarchy" as provided by TARA so that each router is fairly in the middle of the hierarchy and never at the very rim. Analogy: Imagine a city map for Istanbul, Turkey, with a Western part containing each single street and an Eastern part being a highly aggregated road map for entire Asia. Or take Compact Routing studies which mentioned stretch factor 17 !!! Hierarchy is by no means a reason to enforce a path which is longer than the shortest one! Neither when being in the middle or at the rim ("Istanbul"). How many hierarchical levels is the right number? Who says "the less the better" is wrong. I have my doubts that the routing folks have a proper understanding wrt hierarchies. Heiner
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