I don't have the right tech background, but here's an explanation...
A full T1 pipe running at 1.544 Mega bits per second costs about $2,500 per month, including content.
Fractional T1 pipes are sold at $385/month without content. A 128kbps guaranteed throughput with burst capability costs an extra $500/month.
Covad, Northpoint, US West, etc. sell SDSL 1 Megabit and 2 Megabit/sec. service and fractionalized service at prices of $60 to $200/month, BUT THEY DO NOT GUARANTEE SERVICE RATES.
These services use the oversubscription model.
The ISP model is simple. There are 2 pipes, the customer pipe and the backend pipe. The customer pipe is the pipe that goes from the Telephone company to you. The backend pipe goes from the ISP to the Internet cloud via the backbone provider (typically the Telco).
To operate a full T1 will cost the ISP $385/mo. plus $2500/mo. plus the monthly cost of his network and servers (about $500/mo).
The total cost is $3,385/mo.
How can you price it less? by oversubscribing.
divide by 80.
you get $42.81 cost. So US West, etc. make money by oversubscribing their backend. Your pipe may be big, but the backend is clogged, so you will not get much through your pipe connection.
another point.
Even at work, measure how fast you can download via ftp any file. You will see an average of 30kbytes to 80kbytes per second (240kbits to 640kbits). It is common knowledge that the Internet "cloud" is limited to about 400kbits speed. So even if you have a 7meg pipe, the content throughput will still come in at 400kbits/sec.
Example:
when Cable and Wireless took over the MCI Internet accounts, they switched backbones. When I hook up to the new account, my connection speed is 53kbits/sec. However my download is very slow at 200 bytes (1.6kbits) per sec. because the cwix backend pipe is full. My pipe to the cwix POP is clear. But the cwix pipe to the "internet cloud" is clogged.
The recent AtHome round of complaints from Fremont CA are the same type of complaints as the AOL busy signals, and the saying "World Wide Wait"
So, the answer to your ADSL clock timing question is "it depends".
If your connection is guaranteed, and your POP has the information, and you are 1 hop away from your POP, and no one else is on your pipe, then you will get the info quickly.
If your connection is not guaranteed, and your info exists at a server across the Internet Cloud, and you are multi-hops away from your POP, and there are tons of people on the cable modem line logging on to their mail server, then come back after dinner.
Hope this info helps.
BL |
