Network Access via Tether and Other ISPs: A Comparison

Chris Murphy

For the past few years Tether, MIT's dialup IP service, has met the remote access needs of over 2000 users. However, there are times when people may need or want to use alternate methods to access the network, because of toll-call charges, traveling, or a desire for higher bandwidth. This article looks into some alternatives for network access, and discusses their pros and cons relative to Tether.

From a Distance
For users doing a lot of traveling or living outside the local calling area, getting an account with a nationwide or local Internet service provider (ISP) may make sense. There are a few potential problems with this approach, however.

First of all, some services at MIT are restricted to computers with MIT network addresses. Tether is part of the MIT network, and so these services work with no problem for Tether users. Users coming in from other ISPs, however, will not be able to access these services, which include software installers for packages such as Mac OS and Eudora, and commercial services such as Britannica Online. With some of these services (e.g., some installers), IS is working on ways to control access that would let MIT people from other networks install the software, when appropriate. For other installers and services, access restrictions may be beyond our control.

Another issue to be aware of when using an ISP is its connectivity to the Internet at large and MIT in particular. The path that traffic takes from an ISP to get to MIT may not perform well, resulting in poor response from services on campus. Unfortunately, this can be hard to quantify before subscribing to an ISP.

For travelers, having an account with a nationwide ISP can be quite useful when on the road. While the above comments still apply, they may not be of great concern. For example, not many users are likely to install software while on the road.

Most nationwide ISPs provide local numbers for much of the country, but you may find yourself needing to use an 800 number from time to time. ISPs often add a surcharge for the use of 800 numbers, which can be more expensive than a long-distance call into Tether. This is something to keep in mind as you weigh your options.

An alternative to a nationwide ISP account, especially for people doing less travel, is to get an MIT Calling Card (call x3-0122 for details). Calls are billed to an MIT account, which can be very convenient for the occasional traveller.

Cable Modems
A new connection option ­ cable modems ­ has appeared on the scene in the Boston area. Currently MediaOne is the only company offering cable modem access in the area, though it will likely be joined by RCN and Time Warner in the near future.

Cable modem service offers far higher speeds than analog modems (or ISDN): 1.5Mbps download and 300kbps uploads vs. approximately 45kbps downloads and 33.6kbps uploads for the newer V.90 modems. The previously mentioned issues about reaching some MIT services still apply. However, the extremely high speed and low cost ($40/month for current cable subscribers) make this a very attractive alternative.

There are other technologies on the horizon, such as ADSL, for high-speed access. It remains to be seen, however, how well these are deployed in this area, and what the costs will be.

A Word about Expired Certificates
Web certificates came to MIT about a year ago. Personal certificates expire, by default, after 365 days, which means many MIT users may begin to see "expired certificate" warnings. When this happens, you must delete the existing certificate and obtain a new one. For details, go to http://web.mit.edu/ist/help/cert.