{"content":[{"text":"The ISP Column \n A column on various things Internet","bbox":{"left":0.687734,"top":0.079039,"width":0.24133499999999997,"height":0.037600999999999996}},{"text":"July 2021 \n Geoff Huston","bbox":{"left":0.817719,"top":0.150493,"width":0.11127600000000004,"height":0.03228400000000001}},{"text":"CDNs and Centrality","bbox":{"left":0.071764,"top":0.232408,"width":0.24087199999999998,"height":0.02148699999999998}},{"text":"On the afternoon June 17 of this year there was a widespread outage of online services. In Australia it impacted \n three of the country’s largest banks, the national postal service, the country’s reserve bank, and one airline \n operator. Further afield from Australia the outage impacted the Hong Kong Stock Exchange, and some US \n airlines. The roll call of impacted services appeared to reach some 500 services.","bbox":{"left":0.071764,"top":0.269938,"width":0.8572440000000001,"height":0.06421199999999999}},{"text":"The problems were first noticed at around mid-afternoon Australian Eastern Time and were not fully restored \n until four hours later. The question is of course what do these 500 affected enterprises had in common? Why \n were they fate-sharing in an outage? This was not the result of a deliberate attack. But it was related to the \n measures many of the Internet’s enterprises, both large and small, use to deflect the impact of such attacks. \n The answer is that they were all customers of Akamai and in particular Akamai’s Prolexic DDOS protection \n system. Akamai’s post-event response was:","bbox":{"left":0.071764,"top":0.350044,"width":0.857243,"height":0.09642499999999998}},{"text":"ABC News Report on Akami Outage","bbox":{"left":0.132238,"top":0.734322,"width":0.26246500000000006,"height":0.01603500000000002}},{"text":"\"A routing table value used by this particular service was inadvertently exceeded. The effect was an \n unanticipated disruption of service.\" \n https://blogs.akamai.com/2021/06/akamai-provides-prolexic-ddos-service-impact-update-status- \n resolved.html","bbox":{"left":0.132238,"top":0.766535,"width":0.7967560000000001,"height":0.06392700000000007}},{"text":"Yes, the Internet is still growing, and in the IPv4 network we are closing in on some 1 million routing entries, \n and in IPv6 the comparable number is now approaching 150,000 entries. Switching elements implement packet \n decision structures in various ways. Some use Ternary Content-Addressable Memory (TCAM), others use \n customized ASICS. The common objective here is to make a forwarding decision that is based on a lookup of \n a best match of the packet’s destination address to a routing entry drawn from this pool of some 1 million \n entries. And this lookup has to be as fast as we can possibly make it. If I am building a very high-speed switch","bbox":{"left":0.071764,"top":0.846641,"width":0.8572420000000001,"height":0.09614}}],"images_bbox":[{"left":0.132557,"top":0.478578,"width":0.52823,"height":0.239744}],"images_bbox_not_text_overlap":[{"left":0.132557,"top":0.478578,"width":0.52823,"height":0.239744}]}