Renesys has spent some time analyzing Sandy’s impact on the routing table Monday night. They made an animation which shows routes being removed during the storm.
From the article:
Here’s another quick view of the impact on the routing table as Sandy came ashore Monday night. Each square represents the fate of a set of networks geolocated within a common tenth-degree square of the Earth’s surface — at these latitudes, that’s about 90 square kilometers.
At one end of the scale, the darkest green indicates better than 99.95% of the networks are available. At the other end, solid red indicates that more than 5% of the networks at that location have been removed from the global routing table, meaning that they can’t be reached by anyone.
Five percent doesn’t sound like much, but consider the Internet density in the affected areas! In fact, Manhattan’s outage rates were much higher — on the order of 10%, which is impressively low given the fact that ConEd cut power to much of the island. Silencing ten percent of the networks in the New York area is like taking out an entire country the size of Austria, in terms of impact on the global routing table. The 90% that survive are in data centers, running on generator power supplied by engineers who do not sleep much.
It’s striking to observe not only the impacts in NYC, Long Island, and New Jersey, but also peripheral weather-related outages in the Washington DC area, and up the I-93 corridor from Boston into New Hampshire. The Internet has become a sensor network in its own right for determining where storm damage is occurring — and since BGP routing converges in realtime, that information literally becomes available within a few seconds.
MrSeb writes“A team of researchers from MIT, Caltech, Harvard, and other universities in Europe, have devised a way of boosting the performance of wireless networks by up to 10 times — without increasing transmission power, adding more base stations, or using more wireless spectrum. The researchers’ creation, coded TCP, is a novel way of transmitting data so that lost packets don’t result in higher latency or re-sent data. With coded TCP, blocks of packets are clumped together and then transformed into algebraic equations (PDF) that describe the packets. If part of the message is lost, the receiver can solve the equation to derive the missing data. The process of solving the equations is simple and linear, meaning it doesn’t require much processing on behalf of the router/smartphone/laptop. In testing, the coded TCP resulted in some dramatic improvements. MIT found that campus WiFi (2% packet loss) jumped from 1Mbps to 16Mbps. On a fast-moving train (5% packet loss), the connection speed jumped from 0.5Mbps to 13.5Mbps. Moving forward, coded TCP is expected to have huge repercussions on the performance of LTE and WiFi networks — and the technology has already been commercially licensed to several hardware makers.”
iOS: Recommended settings for Wi-Fi routers and access points
The following Wi-Fi base station (or Wi-Fi router) settings are recommended for all iPhone, iPad, and iPod touch devices. These settings will help ensure maximum performance, security, and reliability when using Wi-Fi.
*) route - fix dst-prefix filtering did not return routes when routes with
different routing-mark were present;
*) wireless - improved nv2 stability;
*) winbox & webfig - added simple new version downloading & upgrading panel;
*) dhcp server - immediately store to disk changes for lease configuration;
*) lcd - improve graphs screen
*) lcd - improve touch screen (must /lcd reset-calibration)
*) smb - fix smb share mounting on linux systems
*) ovpn - fixed memory leak on disconnects;
*) userman - fix unpaid profile activation while authenticating;
*) sstp - fix high CPU usage on SSL handshake;
*) winbox - added ability to add time & date to dashboard;
*) metarouter - fixed lockups on RB110AH;
*) metarouter - fixed occasional lockups on RB450G;
*) ups - fixed problem connecting to USB device, introduced in 5.20;
*) quickset - added Wireless PTP Bridge mode;
*) fix MPLS MTU configuration usage;
*) dns - fix empty response;