Hello Moonesamy,
Thanks for your mail.
The 140 GGCs indeed represent the number of Google caches IPs included in the responses of the RIPE Atlas DNS queries and that we further geolocate with our methodology in Mauritius.
We are aware of inconsistency in geolocation databases [1]. But as of today the 10 data sources we used in this work are the only open ones that can be adopted for such purposes.
To carry out a sanity check, we even performed ping measurements with RIPE Atlas probes to select as country of the IP the one from which the mean of the RTTs to the said IP is the lowest.
We however do not have access to any ground truth data against which we can compare such results. Thus, the 140 GGC IPs are the results of the best effort in geolocation that can be done with open data sources as of today.
We are currently working on the journal version of the paper which would detect inconsistencies in geolocation with existing databases by comparing with a proprietary geolocation database.
Moreover, we only study the way IPs allocated by AFRINIC (and not all RIRs) are served by Google/CDNs. That is the reason why it may appear that the number of caches found in Mauritius is higher than the one in Other regions (or countries).
In this case, Google caches in the United Kingdom are shared to serve Africa.
We will look further into the dataset to shed more light on Mauritius in the extended version of this paper.
You can also access to the measurements data available in our technical report [2].
Hope this helps,
Thanks and regards,
Roderick
[1] I. Poese, S. Uhlig, M. A. Kaafar, B. Donnet, and B. Gueye. IP Geolocation Databases: Unreliable? ACM SIGCOMM Computer Communication Review, 41(2):53–56, 2011.
[2] R. Fanou, G. Tyson, P. Francois, and A. Sathiaseelan, Technical Report: African Content Measurement Campaign.
https://techrep_cdma:PDQ7Rjkj_at_fourier.networks.imdea.org/external/techrep_cdma/index/, June 2015
On 07 Jul 2016, at 17:10, Gareth Tyson <g.tyson_at_qmul.ac.uk> wrote:
> Hi there!
>
> Many thanks for the interest in our work :) I've cc'ed Roderick Fanou in (who was the lead author on the work). He'd like to shed some extra insight on the work.
>
> Cheers,
> Gareth.
>
> ---
> Dr. Gareth Tyson,
> CS 404 (Not Found),
> Electronic Engineering and Computer Science,
> Queen Mary University of London.
>
>
> From: S Moonesamy <sm+mu_at_elandsys.com>
> Sent: 07 July 2016 11:41
> To: Gareth Tyson; Arjuna Sathiaseelan
> Cc: mauritius-internet-users_at_lists.elandnews.com
> Subject: Paper about the web ecosystem
>
> Hello,
>
> I read your paper about exploring the African web ecosystem. It is a
> good initiative to have studies about the availability of the web
> content infrastructure in Africa as it is currently not possible to
> understand that given the lack of studies.
>
> I noticed an inconsistency in your data. It is implausible that
> there are 140 GGCs in Mauritius as it would mean that the
> infrastructure in Mauritius is at least three times better than what
> is available in the United Kingdom. The following might highlight
> one of the issues which affect the ecosystem:
> http://www.elandsys.com/~sm/one-km-international-travel.html Web
> performance in Mauritius is, in general, slow. There has been some
> improvements as people understand that what is considered as normal
> is in fact slow.
>
> Regards,
> S. Moonesamy
Received on Thu Jul 07 2016 - 15:25:39 PST