North American Network Operators Group|
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RE: Exodus/C&W Depeering
| Won't this just increase the distance and AS count for Exodus outbound traffic, | making Exodus hosting even less desirable? Only in the minds of people who are lied to by Exodus's detractors. I just spoke with the Invisible Hand of the Marketplace, and it signed (in BSL, so the translation may be off) the following: Usage-based billing: less performance -> less traffic -> lower bill. C&W surely does not want to present a lower bill to you, and thus may be motivated to figure out and correct what's going on. Exodus's customers moving less traffic could take a (hypothetical!) smaller bill to mean unpopular/stale content, or poor performance, possibly near the end user, possibly near the on-Exodus source; if the latter is suspected, distribute the content to elsewhere. (If the former, tell all the politicos you can to stop protecting local-loop monopolists!) A (hypothetical!) larger bill could likewise be taken as either increasingly popular content, or as better performance. A _correlation_ with a change in Exodus's routing policy is not the only possible cause -- someone elsewhere may have done something to widen an intermediate bottleneck. Remember that the AS path is only a trail of breadcrumbs used to avoid route-announcement loops. It is NOT a reliable indicator of the forwarding path towards the destination. An AS-to-AS "adjacency" within an AS path *may* be completely meaningless. You can draw no conclusions about performance (in terms of loss, delay, and delay variance) by examining an AS path, although someone might prove that for a given snapshot, from a given test location, there are strong correlations. Likewise, while from one particular vantage point, a "broader" peering policy correlates with better performance (in terms of things which actually affect goodput, namely loss/delay/delay variance), from other vantage points, there is an opposite correlation. This is not anything remotely like a proof that strict routing and forwarding hierarchy leads to better performance than relaxed routing and forwarding hierarchy, with respect to how traffic is attracted towards a given destination. (Note that one can have strict routing hierarchy, yet still observe a relaxed forwarding hierarchy: consider the case where people do not next-hop-self at LAN-style exchange points). Therefore, anyone predicting that the sky is falling, and big chunks are gonna hit Exodus's customers and C&W (or predicting something opposite) would be lying if he or she claimed to have a better view of the future of this peering policy change than the average employee of the psychic friends network. Sean.