Comcast Service for Non-Cap Bandwidth

PC paul4004 at gmail.com
Tue May 29 16:18:37 UTC 2012


Hi Nabil,

DSCP tagging on inter-domain internet traffic is not expected to work (I
wouldn't expect this to work at any ISP, quite frankly, absent some very
special arrangements).

>From reading the article in the link below, it sounds like they are using
DSCP to ensure when a user has maxed their bandwidth allotment (say,
downloading the latest WOW update), that TV viewing is not disrupted.
Instead of providing QOS on it to do this, it seems they provide you an
included-with-the-service additional bandwidth allotment/connection not
related to your internet connection, much how normal video is sent.  In
theory, this service could work if you cancelled your internet.  In
reality, it probably won't.  Many providers do the same for VOIP traffic if
they have phone services, etc (which do often work with no internet
service).

I will say this -- I do telemetry data distribution which is nothing more
than a 1.5 megabit constant UDP stream (multicast anyone?  I wish).  The
amount of traffic I push is roughly ~350gb/month per site.  With hundreds
of business account sites on Comcast, Verizon, AT&T, cox, and others -- The
statistics don't lie.  The Comcast network has the least packet loss of the
bunch by a wide margin in many cases, and in my opinion, is the most well
built consumer broadband access network out there.  With forward error
correction, It's an extremely rare event that I see any requests for
retransmission, generally isolated to maintenance activities.

My suggestion?  Just send your data towards comcast from a Tier 1 ISP.  Get
it as close to your users (geographically) as you can, or use a CDN.  Then,
I think you will be fine.

As for the connectivity, you might find it a good idea to explore the
comcast paid peering/transit solution if comcast is your primary
destination and packet delivery is critical.  Heavy NDA requirements
resulting in lack of general pricing range input from the community every
time the question has come up on NANOG has kept me from inquiring about
paid peering.  But I will tell you just purchasing from the many transit
providers who do publish pricing has not resulted in any problems or
congestion, which is a good sign.



On Tue, May 29, 2012 at 9:25 AM, Livingood, Jason <
Jason_Livingood at cable.comcast.com> wrote:

> Mail formatting issue with my mail client again… Note that the 1st
> paragraph was quoted from Nabil...
>
> >I generate http test stream with DSCP code point 5 to match the Xbox
> service,
> > however Comcast is rewriting the packets as CS 1, even when serving out a
> > server at Soft Layer (paid peer).  This is why I ask for name of service
> Microsoft
> > is using, it is not the regular paid peering.
>
> [JL] Yeah, that won't work but that marking is just for byte counting
> (which per my other not does not really have any effect now anyway since
> the 250GB policy was suspended. See also
> http://blog.comcast.com/2012/05/the-facts-about-xfinity-tv-and-xbox-360-comcast-is-not-prioritizing.html
>
> For peering & interconnect, see:
> http://www.comcast.com/peering/?SCRedirect=true
> http://www.comcast.com/dedicatedinternet/?SCRedirect=true
>
> Thanks
> Jason
>



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