Articles By Doug Madory

Satellite Service Sets in Lebanon

Early last month, my blog "Pinning Down Latency" included this prediction:

In the coming weeks we expect to see a dramatic shift in transit as Lebanese providers move away from expensive and high-latency satellite service to IMEWE-based service.
Well, it didn't take long for this to play out.

Cyber Attack in Palestine?

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We can confirm reports of significant but sporadic Internet outages in the Palestinian Territories today.  As many as half of the routed networks of the Palestinian Territories were unreachable (withdrawn from the global routing table), possibly as a result of reported cyber attacks.  These outages are the largest we have observed all year for this country, which normally has a fairly stable Internet.  Impacted networks are located in both the West Bank and Gaza Strip.

 


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Large Outage in Pakistan

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For about 3.5 hours today, almost half of the Internet in Pakistan was down. Renesys observed 46% of the routed networks of Pakistan withdrawn from the global routing table between 19:37 and 23:02 UTC making this the largest Internet outage we have observed in the country in recent years.

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Pinning Down Latency

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Packet latency is a big issue in Internet-based applications (i.e. the stuff in the cloud). In conducting analysis on Internet infrastructure over the years, we have seen many patterns of connectivity. One such pattern that can wreak havoc on latency is "hair-pinning", a phenomenon where traffic takes an unnecessarily long physical path between two points on the Internet due to suboptimal routing. The increased distance results in increased latency, and the "lag" or "sluggishness" that users experience as a result can hinder latency-sensitive online applications whether they are financial trading applications or MS SharePoint. hairpins.jpg

Remember when the telephone company came to your house to hook up your phone and gave you a new phone number? This new number was how your friends and family were going to contact you. You counted on the telephone company to ensure that someone hadn't already been issued that number, because if they had, various problems would ensue. What would happen when your mom tried to call your number if it was also assigned to someone else? Could you directly call the other party to work out the problem? Well, in the BGP realm, something similar has been happening with autonomous system numbers (ASNs).

Organizations need an ASN to run BGP and route on the Internet. They are each assigned globally unique ASN(s) by their local Regional Internet Registry (RIR), who get them from IANA. A few weeks ago, the NANOG folks noticed that AS1712 had been registered by two different organizations (in France and Texas) that were both using the number to announce their separate network prefixes. ARIN issued a statement conveying that they were aware of the problem and were working to resolve it. We took a look at the data and found that AS1712 isn't the only dually-assigned ASN out there. In fact, even a root server didn't escape unscathed.

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Our weblog is written by a variety of Renesys employees. They run the gamut from senior execs and engineers to sales guys. Anyone who has something to say that could be informative or of interest to our customers and visitors, says it here.

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