[133975] in North American Network Operators' Group
Re: Some truth about Comcast - WikiLeaks style
daemon@ATHENA.MIT.EDU (Owen DeLong)
Mon Dec 20 18:37:12 2010
From: Owen DeLong <owen@delong.com>
In-Reply-To: <201012201647.22870.lowen@pari.edu>
Date: Mon, 20 Dec 2010 15:36:03 -0800
To: Lamar Owen <lowen@pari.edu>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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.
>=20
>> This means that average DSL speeds are sub-T1.
>=20
> 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.=20
>=20
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.
>=20
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.
>=20
> Their copper in my area is nearly new, they have spent the last five =
years or so refreshing and updating their copper outside plant. =20
That helps a lot. It still doesn't compete with CMTS which was my point.
Owen
