Archive for the 'Topology' Category

2001:deba:7ab1:e::effe:c75

Tuesday, January 22nd, 2013 by Robert Beverly

[This blog entry is guest written by Robert Beverly at the Naval Postgraduate School.]

In many respects, the deployment, adoption, use, and performance of IPv6 has received more recent attention than IPv4. Certainly the longitudinal measurement of IPv6, from its infancy to the exhaustion of ICANN v4 space to native 1% penetration (as observed by Google), is more complete than IPv4. Indeed, there are many vested parties in (either the success or failure) of IPv6, and numerous IPv6 measurement efforts afoot.

Researchers from Akamai, CAIDA, ICSI, NPS, and MIT met in early January, 2013 to firstly share and make sense of current measurement initiatives, while secondly plotting a path forward for the community in measuring IPv6. A specific objective of the meeting was to understand which aspects of IPv6 measurement are “done” (in the sense that there exists a sound methodology, even if measurement should continue), and which IPv6 questions/measurements remain open research problems. The meeting agenda and presentation slides are archived online.

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IPv6: What could be (but isn’t yet)

Monday, June 4th, 2012 by Matthew Luckie

With IPv6 Launch approaching, there is increasing interest in measuring the readiness of the IPv6 infrastructure. A major concern, particularly for networks that source or sink content, is the performance that is achievable over IPv6, and how it compares to the performance over IPv4. A recent study by Nikkah et al. argues that data plane performance, as measured by web page download times, is largely comparable in IPv4 and IPv6, as long as the AS-level paths in IPv4 and IPv6 are identical.  We have confirmed these findings with our own measurements covering 593 dual-stack ASes: we found that 79% of paths had IPv6 performance within 10% of IPv4 (or IPv6 had better performance) if the forward AS-level path was the same in both protocols, while only 63% of paths had similar performance if the forward AS-level path was different.

Given the apparent importance of congruent AS-level paths in IPv4 and IPv6, we measured to what extent such congruence exists today, and how this has evolved historically. We measure IPv4 and IPv6 AS paths from seven vantage points (ACOnet/AS1853, IIJ/AS2497, NTT/AS2914, Tinet/AS3257, HE/AS6939, AT&T/AS7018, NL-BIT/AS12859) which have provided BGP data to Routeviews and RIPE RIS since 2003. The figure below plots the fraction of dual-stack paths that are identical in IPv4 and IPv6 from each vantage point over time. According to this metric, IPv6 paths are maturing slowly. In January 2004, 10-20% of paths were the same for IPv4 and IPv6; eight years later, 40-50% of paths are the same for six of the seven vantage points.

Fraction of identical dual-stack paths over time

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Shutting the phone network off while you’re running out of internet protocol numbers

Friday, January 20th, 2012 by kc

I ended 2011 with a short (20 December) visit to a pleasantly warm Washington, D.C. for my 5th FCC Technical Advisory Council meeting. Some of the discussions from the third meeting were extended, others cut off for lack of time. We spent over an hour on the suggestion made by the Legacy Transition working group two meetings ago to advise the FCC to move forward in sunsetting (although we shunned that term at this meeting — “It’s a new beginning, not an end!”) the public-switched telephone network (PSTN). Many questions have arisen repeatedly in the discussions over the course of the last two meetings (and two FCC workshops in between), notably, “What happens to the telephony numbering system?” The initial strategy was imprecise, “The numbering plan will continue to exist but governance and allocation process needs to be considered.” Another repeated question has been “What exactly do we mean by PSTN?”

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Model for Internet Evolution Predicts Consolidation in Tier-1 Transit Market

Friday, July 15th, 2011 by Amogh Dhamdhere

Although the outcome is not good news, it is gratifying to see the predictions of a model of the Internet ecosystem being validated by the real world. Specifically, the recent spate of ISP consolidations is precisely what our network formation model predicts. First, Level3 acquired Global Crossing in a deal valued at $3B. A few months later, Centurylink (QWEST) acquired Savvis for $2.5B. Our model predicts that this consolidation will continue unless ailing tier-1 providers find a new source of revenue to compensate for their losses on IP transit.

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CAIDA participation in IPv6 day

Sunday, June 5th, 2011 by kc

On June 8 2011 a group of content providers, including Google, Yahoo and Facebook, are going to dual-stack their content, in an event called World IPv6 Day. This trial will enable content providers to gain experience with increased levels of IPv6 traffic and gauge the extent and effect of broken dual-stack end-users. CAIDA is cooperating with RIPE NCC’s measurements on this day, providing a dozen Ark monitors to increase the number of vantage points from which RIPE will actively test a set of dual-stacked websites for levels of IPv6 support: existence of AAAA records; ping/ping6 response; traceroute/traceroute6; and HTTP reachability.

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Exhausted IPv4 address architectures

Tuesday, May 3rd, 2011 by kc

In light of available data on global IPv6 deployment, ISPs, and those who build equipment for them, have already accepted that multi-level network address translation (NAT, between IPv4 and IPv6 networks) is here for the foreseeable future, with all its limits on end-to-end reachability and application functionality, and its required unscalable per-protocol hacks. Whether “carrier-grade” NAT (CGN) technology supports a transition to IPv6 or becomes the endgame itself is irrelevant to the planning horizon of public companies, who must now develop sustainable business models that accommodate, if not support, IPv4 scarcity. I’ve heard a few notable predicted outcomes from engineers in the field.

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CAIDA’s IPv6 measurement and analysis activities

Friday, April 29th, 2011 by kc

In pursuit of more rigorous data on IPv6 deployment, CAIDA has undertaken four IPv6 measurement and analysis exercises: address allocation data; traceroute-based topology; DNS queries from root servers; and a global survey of network operators in 2008.

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annotated bibliography of IP geolocation papers

Saturday, April 23rd, 2011 by kc

Many applications require the association of Internet numbering resources with an accurate geographic label at some granularity. For some applications, knowing the country of origin might be sufficient; for others a more precise indication at state, city or zip code granularity, or even a specific latitude/longitude is needed.

However, which method(s) work best? Which database sources and services are most reliable, at what geographic resolutions? If a data source provides the geographic location of the owner of an IP address, is this location the same as the location where the device is actually broadcasting and receiving packets? And, if different, can the difference be quantified?

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Unsolicited Internet Traffic from Libya

Wednesday, March 23rd, 2011 by Emile Aben

Amidst the recent political unrest in the Middle East, researchers have observed significant changes in Internet traffic and connectivity. In this article we tap into a previously unused source of data: unsolicited Internet traffic arriving from Libya. The traffic data we captured shows distinct changes in unsolicited traffic patterns since 17 February 2011.

Most of the information already published about Internet connectivity in the Middle East has been based on four types of data:

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Caidagram: visualizing geographically annotated Internet measurements

Monday, February 28th, 2011 by Claudio Squarcella

I post this article to describe the results of my five month visit to CAIDA and UC San Diego, and to thank the organizations that collaborated to make this work possible.

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