Some truth about Comcast - WikiLeaks style

Rettke, Brian Brian.Rettke at cableone.biz
Tue Dec 21 16:26:48 UTC 2010



Sincerely,

Brian A . Rettke
RHCT, CCDP, CCNP, CCIP
Network Engineer, CableONE Internet Services


"-----Original Message-----
From: Lamar Owen [mailto:lowen at pari.edu]

Interestingly enough, we've tried to do H.323 with some folks on a CMTS connection, and have yet to succeed in smooth video.  My testing on my home DSL, back when it was 1.5M/.5M (we got two free upgrades; the first one was to 5/.5 and the second to 7/.5) and our main link was an OC3 to a different provider, went well.  Never really figured out what it was causing the problems with the CMTS users; the effect was that the H.323 session would start up and negotiate at 384Kb/s, and a few seconds of video would traverse fine, and then the link would start dropping more and more frames until it died entirely; my testing on my slower DSL didn't have this problem, and traceroute showed an equivalent number of hops between.  The CMTS connection in use was an 8M down 1M up link."

The problem is probably not the connection speed, but congestion on the CMTS. If the downstream is saturated (too many people watching Netflix on a node) the available shared bandwidth may not be enough to support your real-time traffic. Which is a pretty good archetype for the discussion anyhow.





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