- By Jeff Field -
With the growing availability and popularity of cable modem service in many areas, a lot of people, Linux users included, are purchasing their own cable modems. This can save on monthly lease fees and other costs associated with leasing a cable modem from the provider. However, I recently picked up a leased 3Com 3CR29223 HomeConnect Cable Modem, and here are my experiences, including some curious behavior with Linux.
When the cable modem arrived, I was given instructions by my service provider, Comcast@Home. Comcast said it should be simple -- I would just plug it in and everything would work. So, I disconnected the old Motorola cable modem that I have had for a couple years now; that one was not only huge, but capped out at a 15k upload speed. The procedure for installing the new modem was much like the old one -- patch cable into my hub's uplink port, coax into the back, power connection to my surge supressor. Comcast said it would take up to two hours for it to connect -- it was actually around an hour and a half.
Once the modem had grabbed a connection, I tried to grab my IP, but no luck. So, I called Comcast, and customer service told me I would have to change the name on my PC and read the other four machines. (Yes, I pay for extra IPs, and I know a router would probably serve me better.) Comcast never said this would be necessary -- my entire internal network was based off those particular addresses and IPs. So I ordered the new addresses and set everything up. This is when I ran into an interesting problem under Mandrake Linux; previously, I could just pick up the IP via DHCP, but something happened when the change occured, and I had to manually set up the network configuration. Once that happened, I brought up eth0 and noticed the packet light on my NIC going, a good sign indeed. I SSHed into a shell at one of my ISPs, which confirmed that everything was running properly.
The modem itself does everything I could want -- it sits behind my desk, it blinks, and it stays connected. It has a number of status lights, something my previous modem did not have (beyond power and connection status), but they are of limited use. One is a transfer light, which is more annoying than useful, because it blinks almost constantly, the other is some sort of "programmable" light that your ISP can set to blink when certain things happen, such as when you get email.
We received the 3Com modem as a free upgrade because Comcast was phasing out the old Motorola we were leasing previously. Even if we had purchased our last modem, we would still have to upgrade now. The problem for early adopters of cable modems is that they may be forced to upgrade to these new DOCSIS-complaint modems. DOCSIS is a common protocol for cable modems to speak to cable providers. Earlier modems probably did not support DOCSIS. For people who bought a cable modem, this means shelling out another $200 for a modem. For people who leased, it simply means a call to your cable provider and a couple of hours downtime. In the end it seems worth it - many old modems had caps on upload speed (the cap on my modem was 15KB/second) and these caps have probably been removed, in my case increasing my upload speed to as much as 120KB/second. That is an 8-fold increase in speed.
So, the real decision comes down to this - should you lease, or should you buy your modem? For our service, it is an extra $8 a month if we lease the modem. One benefit to leasing is that if the modem breaks or becomes obsolete, the company will provide you with a new one, no matter how long after you begin leasing it. And in our case, leasing paid off. At $8 a month for a little over two years, the cost is a little less than buying this new modem -- so, if I get another modem (via upgrade or broken modem) in the next two years, I will again at least "break even" on the deal. With a purchased modem, it would cost $32 a month, only slightly more than a dial-up ISP and a second line to run it on, but if the modem breaks I'm on my own.
The modem is excellent. It has yet to disconnect or have any service issues since I got it a few weeks ago. The service is also very nice. For those few dollars over what you'd pay for a standard ISP, you get 24/7 connections and all sorts of extra bandwidth, something many Linux users can appreciate, especially when updating all those nice large packages over the Internet.
If you are in the market for cable service, and have decided to purchase your own modem, check out the 3Com 3CR29223 HomeConnect; it is a relatively inexpensive model that has been very reliable for me. It can be found for around $250 on Pricewatch.