🚀 go-pugleaf

> <sigh>  It's not just "one porn server" -- that's disingenuous spin by
> cable MSO's.  Data is data -- the problem is the same whether
> subscribers are running a webcam, uploading big PowerPoint
> presentations, mailing family photo albums, and/or mailing home videos.
> 
> Regardless, typically no one cable user can use a disproportionate share
> of capacity in any event 

Due to slotting/throttling algorithms, I assume.

>-- the issue is the total usage of the uplink
> and the lack of graceful degradation at the point of saturation. 
 
Understand.

What is the typical *total* amount of upstream bandwidth avail on a
given
segment?

We're getting closer to the key metric to compare cable with DSL: 
   *Upstream oversubscription rate*

If you look at ADSL at two different layers you get the following:

(Alcatel DSLAM has 576 ports, 256Kbps upstream cap, 45Mbps DS3 uplink)
Cust -> DSLAM: 576 * 256,000bps / 45,000,000 that's 3.2:1

(Aggregation router port might terminate 2-4K subs, 256Kbps upstream
cap, 45Mbps DS3 uplink)

2K:
Cust -> Aggregation Rtr: 2000 * 256,000bps / 45,000,000 = 11:1

4K:
Cust -> Aggregation Rtr: 4000 * 256,000bps / 45,000,000 = 22:1

So uplink oversubscriptiong is effectively somewhere between 10:1 and
25:1.

How do you think this plays out for cable modem?
-- 
-------------------------
Lawrence Baldwin
Protocol Scientist
678-624-0924
http://www.mynetwatchman.com - I'm under attack, now what?