Hi Everyone,
According to my timeline, this week I'm supposed to implement the services
connectivity sub-module. I've spent the entire day looking into different
services and their protocols etc. I also looked into existing mechanisms and
came across something interesting and directly relevant to our work. It's
called Glasnost. Basically, it has a client/server architecture based on
flows to detect "differentiation" of different kinds of traffic by ISPs.
Differentiation is an umbrella term for blocking, throttling etc. Here's the
project website: http://broadband.mpi-sws.org/transparency/glasnost.php and
here's a link to a research paper about the system:
http://broadband.mpi-sws.org/transparency/results/10_nsdi_glasnost.pdf
The paper is a must read for everyone involved in the ICM project. Other
than the mechanism, it has some very nice design considerations that we
should follow as well.
In a nutshell, if we want to check if BitTorrent is being differentiated, we
would start two TCP flows to a server from the user client. One flow would
have BitTorrent headers and content in the payload while the second (sent
after an offset interval) would have random bytes in the payload. We would
run both flows for X time for the protocol to stabilize. If there's a
problem with Flow 1 and not Flow 2 then that would mean that Flow 1 is being
differentiated. This can also be used to check if there's any throttling of
Flow 1 as compared to Flow 2. One important point that they make is that
port number is not the only parameter that ISPs use to differentiate
services, in fact ISPs also employ techniques based on the content and
protocol behaviour to find out the type of the service. This is something
that we should consider as well.
So, this is what I propose. We should use the same mechanism for our service
connectivity tests. But that leads to a architectural question. What would
the measurement servers be in our case. Well that's something that we need
to decide. I think we have three options for the measurement servers: 1) The
super peers, 2) Server code hosted on M-Lab like platforms, 3) Existing
Glasnost servers.
What do you guys think?
--
Best,
__
Zubair
------------------------------------------------------------------------------
EditLive Enterprise is the world's most technically advanced content
authoring tool. Experience the power of Track Changes, Inline Image
Editing and ensure content is compliant with Accessibility Checking.
http://p.sf.net/sfu/ephox-dev2dev
_______________________________________________
Umit-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/umit-devel
