[Iccrg] Testing ECN support for UDP flows

[Ingemar Johansson S]

Hi

Sorry for the cross-post, I would believe that it is best to reply to tsv-area only.

I have previously asked people regarding the support of ECN especially for UDP flows.. There seems to be a lot of uncertanities around this and in general it is difficult to get any clear view (if there is any ?)
So... how do I best test this on a larger scale ?

1) UDP port 7: The idea is to ping other host with UDP packets on port 7, some of the packets are ECT(0)/(1) marked, some are not. If I get things right, port 7 is not genarally enabled these days, are there any host around that are known to leave port 7 open. 

2) Modified STUN client: The idea is to do STUN requests to a number of STUN servers. Some of the STUN requests are ECT.

3) Setup a mesh of volountary hosts that installs a software that agrees to communicate via a specific port, the hack would need to implement some means to communicate NAT'ed addresses etc. This would require some logistic effort to gather up volounteers for the test-fest. 

Ideally the test should be able to tell if possible ECN issues are located close to the user (e.g firewalls, WLAN routers etc) or in the core-networks. Also I believe that running UDP would be beneficial even though I know some people have already tried with ICMP.

Which would be the best alternative in order to do such a test ?, comments/suggestions are welcome. 

Regards
Ingemar

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Ingemar Johansson 
Senior Research Engineer, IETF "nethead" 
EAB/TVK - Multimedia Technologies 
Ericsson Research Ericsson AB 
Box 920 S-971 28 Luleå, Sweden 
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