Some truth about Comcast - WikiLeaks style

Owen DeLong owen at delong.com
Mon Dec 20 23:36:03 UTC 2010


On Dec 20, 2010, at 1:47 PM, Lamar Owen wrote:

> On Monday, December 20, 2010 03:44:33 pm Owen DeLong wrote:
>> The vast majority of residences are more than 5,000 and a good majority
>> are more than 10,000 cable feet from the CO.
> 
>> This means that average DSL speeds are sub-T1.
> 
> FWIW, I'm at 14-15 kilofeet from the CO, and am getting a solid 7Mb/s down and 512kb/s up.  The ISP has three tiers of DSL, and I'm at the lowest (which is probably the one that will work at my distance).  They also provide a 9M down / 768k up, and a 11M down / 1M up for slightly higher rates.  I'm told that the 11 down/1 up will work up to 12 kilofeet by their engineering. 
> 
Those are all still sub-T1 on the uplink and well below normal CMTS service
speeds. Low-end CMTS is around 15Mbps/7Mbps.

> I'm running a secondary administrative DSL at my employer's location at the full 7/.5 rate at a distance of nearly 18 kilofeet, the last 2 kilofeet being our inside plant of CAT3 CALPETH.  That is on a Cisco ADSL WIC in a 2651; show dsl interface atm0/0 shows a downstream rate of 6.8Mb/s and an upstream of 640kb/s.  Not bad for the distance.  Margins are good on both directions, being 12dB upstream and 8.5dB downstream.
> 
I'm happy for you. The AT&T cable plant in my neighborhood is unable to
sustain any better than 1.5mbps/384k on ADSL.

> My experience is that the downstream is mildy oversubscribed, and the upstream less so.
> 
> Their copper in my area is nearly new, they have spent the last five years or so refreshing and updating their copper outside plant.  

That helps a lot. It still doesn't compete with CMTS which was my point.

Owen





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