Sucking Mud Through a Straw

Tom Kelliher, CS 318

Mar. 10, 2000




Read Chs. 23 and 24.

From Last Time

IP addresses, routing.


  1. Sharing the bandwidth.

  2. Protecting sensitive systems.

Coming Up

Socket programming

Sharing the bandwidth

  1. Hardware costs: constant dollars, exponential increase in power.

  2. Internet bandwidth costs: constant dollars, incremental increases:
    1. Typical ISP $20/month, 50 Kbps downstream, 33 Kbps upstream.

    2. @Home $40/month, 500 Kbps downstream, 128 Kbps upstream.

      ADSL more expensive, less bandwidth.

    3. @Work about $400/month.

    4. T1: $1,200/month (?), 1.5 Mbps (duplex?).

    These costs are fairly constant.

  3. Use is growing exponentially: MP3 today, DVD tomorrow.

  4. Here, the bottleneck shifts. Router today, T1 tomorrow.

  5. Expense.

  6. Conflict: ``work'' use vs. ``play'' use. The solution? (Multiple campus networks; multiple Internet connections.)

Another example: the firewall.

  1. If all campus systems are on the same network, how do you protect sensitive systems?

  2. External threats: use a firewall.

  3. Why allowing visibility to some machines is bad.

  4. Internal threats. Standard attacks. Password sniffing if telnet is used.

  5. The solution? ((different) Multiple campus networks; multiple firewalls, secure access applications, static IPs to ensure connections only from authorized systems.)

Thomas P. Kelliher
Fri Mar 10 11:58:38 EST 2000
Tom Kelliher