Testing Free's FTTH
French ISP Free has, over the years, gathered a core of fanatic customers who like to disect every announcement, product or performance data related to the company. You have Freenews, le Journal du Freenaute and undoubtedly others I don't know as well.
With Free opening its service in Montpellier a few weeks back, the people at Journal du Freenaute actually took a trip down to the south of France to test the service. They kindly agreed to let me translate the article they did about that test. I should add that I don't understand all the technical aspects of what I'm about to post, but I think it will be of interest to some of you...
Passing through Montpellier on Friday (Jan 25th) the Journal du Freenaute was able to have access to a working Optical Freebox and proposes the following bandwidth tests we performed on it.
The Optical Freebox we were able to test was connected to the Bérard ODF, detected four days ago (and whose inside photos we will show to you very soon).
This Freebox is absolutely identical (both in terms of hardware and firmware) to those installed for the early Free customers in Paris and Montpellier. The only difference is that it's connected directly to the Cisco Catalyst 4500 switch via a 20m cable, which ensures an optimal connection. However, considering that attenuation due to distance is minute on an optical fiber (compared to our good old copper pairs) we can consider that these performances do reflect the average performance of Free's current FTTH offer.
Latency tests (ping)
On thing we felt was interesting to know about these FTTH connections is the latency between the subscriber's computer and the optical switch in the ODF. Indeed the latency between the different routers in the network (to go from Montpellier to Paris, for example) will be identical whatever technology is used (optic fiber, copper, cable) to connect the subscriber to the rest of the network.
So we performed a ping from the PC connected to the Freebox towards the optical switch. Unlike with xDSL, where latency is 7-8 ms, it is here inferior to 1 ms (just like on a LAN). We then decide to perform a ping to a network equipment within Free's network in Montpellier, but outside the Bérard ODF (in this instance, a DNS server).
To our surprise, latency is still most often under 1 ms!
Bandwidth tests
As Frédéric Gander explained on our newsgroup yesterday, bandwidth over long distances can be slowed down by the TCP window. Therefore, in order to test the download, we adopted several techniques.
Traditional test: FTP transfer
First of all we wanted to test the potential bandwidth for FTP downloads. In order not to be limited by the distant server (bandwidth per connection limitations) or by the TCP windown, we launched several simultaneous downloads.
Cumulated FTP download rate: 10,9 Mo/s, ie. 87,2 Mb/s
Then we performed an upload test to a server located in Paris. One trial was enough to reach the maximum:
FTP upload rate: 5,6 Mo/s ie. 44,8 Mbit/s
Pure bandwidth tests with Iperf
Iperf is a software that allows to test a portion of a network by placing a server on one side and a client on the other. Iperf sends TCP packets over the link but does not write anything on the client or server hard drives which avoids being potentially limited by the drives' speed.
It is also capable of modifying the size of the client's and server's TCP window, which limits the potneital issues related to it. In this instance, the download rate was obtained without having to modify the size of the TCP window.
Before we left for Montpellier, we set up several Iperf servers on machines that are physically in Roubaix (OVH datacenter) using teh following command : iperf -s -w 500k
Here are the results obtained by running Iperf on the client with the following command: iperf -i 1 -w 500k -c server_ip
Download : a little over 94 Mbit/s
Upload : a little above 45 Mbit/s (no screen capture for this test, sorry)
Conclusion
These few tests demonstrate that the performances of the Optic Freebox are there and correspond (roughly) to the advertised characteristics : 100 Mbits download and 50 Mbits upload.
These rates should offer a true improvement of the quality and usage comfort of many services. With TV Perso, the quality of live broadcasts will be comparable to that provided by other Freebox TV channels. Another example, HD TV becomes accessible to everyone and on several terminals (HD box, multiple TVs etc.) with an optimal quality.
Another strong suit of the fiber connection is its reliability, which should allow the development of services like video surveilance, domotics, home medical assictance, etc.
Optic Fiber seems to fulfill its promise, and there is little doubt that its widescale deployment will allows the development of new applications no one is thinking of just yet...
- Find all our articles on Free's FTTH Offer here and other photos of the Optic Freebox in the Gallery."
