Cable Companies and IP

Factual Questions
1

Excite@home is shutting down in Feb. Comcast & Cox use that as their entryway into the web for us who subscribe to them. They both have cable networks, which hey use for TV. AT&T did use Excite@home, but it had to set up its own network, and has mostly accomplished that.

What exactly does a cable company, such as Comcast, have to do to be a self-contained IP, complete with email and access to the web? It has the cables. Apparently, they lack the “network.” What does that mean? Does it mean they have to tie the cables together in some physical manner? In some electronic manner? Or what.

2

I am not a network engineer, but some of the things I believe must be in place:

Network routers
Servers
A hard connection to the actual Internet (think of the cable system as just the wiring inside a building)
Some sort of programming/software that permits two-way communication

Someone who knows what they’re doing would be a great help, but as we’ve all come to learn, it’s not absolutely necessary in the ISP game.

3

A closer analogy might be having a computer with a modem and a phone line…without an ISP, you can’t do anything with it (please, let’s not delve too deep into the analogy).

It’s reasonable to assume that there are already routers in place; presumably Comcast/Cox had been routing all traffic through a wide pipe (like an OC-5) to @home, which was then sending it out on the net.

In addition to a cable/router infrastructure, an ISP needs to provide:

Mail servers
News servers (although some ISPs are outsourcing or eliminating this)
Proxy servers (optional)
Filters (my ISP, Optimum Online, started filtering port 80 to restrict the growth of the Code Red worm)
DHCP & DNS servers (sometimes these are done with routers)
Redundant connections to the internet (preferably using separate carriers)
And, of course, tech support.

4

I posted this in the other thread before I noticed the double-OP.

Your local broadband provider provides only the “metropolitan area network” or MAN. This would let you talk to your neighbor, the guy down the street, or a business half-way across town, but it won’t let you get to the Internet. That’s what Excite@Home does: they provide the “wide area network” (WAN) connection that lets you get onto the Internet as a whole. Excite@Home owns (well, actually, leases, from AT&T) the network connectivity that lets cable modem users get anywhere on the world.

What is needed to be an Internet service provider is (a) some means for your customers to connect to you, (b) some means for you to connect to the rest of the Internet, and © a router to connect these two systems together. (Other things, such as email servers, are generally also used, but these are not absolutely fundamental to the basic function of providing network access.)

In the case of a dialup service provider, (a) is a modem rack and a lot of phone lines, (b) is a high-cap data connection, usually either a high-cap copper or optical fiber line directly to one of the large data backbone providers like WorldCom, Sprint, Qwest, or AT&T, and © is a device known as a “router”. The ISP’s routers concentrate the data from all its relatively low-speed user connections onto its high speed connections, and sort out the data coming back from those high speed connections for distribution to users.

In the case of a cable modem provider, the only thing that changes is the telephone-based network is replaced by the cable network. Instead of a modem rack and phone lines, the ISP installs what is called a “cable modem termination system” (CMTS) like the Cisco uBR7200. These devices pull the data packets off the cable the same way a telephone modem pulls them off a phone line. (A CMTS is basically a lot of cable modems smashed into one box.) Once the packets get to the ISP, they get treated the same way.

Excite@Home provided the routers and the high-speed data connections to each participating cable company (as well as some other services, like email and news). The cable companies merely provided the cable modem network. So, what the cable companies left in the lurch by Excite@Home have to do is obtain their own routers and their own high speed connections. For some, like AT&T, this is trivial: AT&T already owns a huge high-speed network and can easily repurpose or buy the necessary equipment. Others, like Cox, have to make arrangements with other companies to get the high-speed network access.