nanog mailing list archives

Re: Observations of an Internet Middleman (Level3)


From: "Livingood, Jason" <Jason_Livingood () cable comcast com>
Date: Fri, 16 May 2014 14:58:57 +0000

On 5/16/14, 7:56 AM, "Vinny Abello" <vinny () abellohome net> wrote:

I think he's questioning why packets from speedtest.comcast.net have CS1
if everything is supposedly equal, and what that is used for. A quick
Wireshark shows that to be true right now running to your Plainfield, NJ
speedtest site, and my network peers directly with Comcast.

I'm kind of curious too. What is the purpose of this? Is it the
traditional purpose of CS1 to be less than best effort or something
else? If this is the case it seems Comcast would be purposely putting
themselves at a disadvantage in speed tests when congestion is
involved... or is this possibly on purpose to make peering problems look
even worse during congestion?

Ah! That makes sense now. CS1 is used internally to mark best effort
Internet traffic. This has often caused confusion when folks see our
markings. If folks want to send me any data off-list that you think merits
further investigation, let me know (never know if something someplace is
an honest config error).

Jason


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