CS 363
Winter 1999
Homework 1
Instructions:
- This homework is to be completed on your own, with no help from classmates or friends. Use all books and websites you can find as resources.
- This homework is due at 12noon on Thursday, 21 January, 1999.
- Completed homeworks should be e-mailed to
cs363@sadler.atd.depaul.edu Homeworks can appear in plain text as the body of the mail message or as an attachment. I can read Word ’97, html, and rtf formats.
Homework answers will be posted to the class website at the due time, so no late assignments will be accepted.
Problems:
- (10 points) Your company has just decided to install a network for the first time. You have been asked to specify configurations for your 120 servers. Because of heavy data load anticipated on the network, it’s essential that the servers keep up with significant amounts of traffic. Your manager has asked you to put together a "killer server" to keep up with the demand.
- Required Results: the server must be able to handle all the network traffic it receives "with reasonable response time."
- Optional Desired Results: Because some network segments are busy and others relatively idle, you’ve been asked to keep the hardware costs to a minimum. You need to make sure the server won’t slow the network down.
- Proposed Solution: Because of high demand on one segment, you’ve gotten approval to buy 32-bit bus-mastering NICs with additional RAM for all segments. Which results does the proposed solution produce? Why—explain in full?
- The required result and both of the optional desired results.
- The required result but only one of the optional desired results.
- The required result but neither of the optional desired results.
- The proposed solution does not produce the required results.
- (10 points) An advertising firm decides to install a network to link all the employee’s computers together. The company plans to introduce some video teleconferencing software across the board and plans to use e-mail and database applications heavily. Because of the anticipated load on the network, you want it to be as fast as possible.
- Required Result: The network must operate at speeds of up to 100 Mbps.
- Optional Desired Results: The cabling should be as inexpensive as it can be. Also, since you have to do the work yourself, you want it to be easy to install.
- Proposed Solution: You suggest using Category 5 UTP and hubs to connect all the workstations. Which results does this proposed solution produce? Explain in full.
- The proposed solution delivers the required results and both of the optional desired results.
- The proposed solution delivers the required results but only one of the two optional required results.
- The proposed solution delivers the required results but neither of the optional desired results.
- The proposed solution does not deliver the required result.
- (10 points) Berts, Inc., has decided to bring mobile computing to its field engineers. Each field engineer is to be supplied with a laptop, a portable fax/printer, and some kind of wireless transmission device.
- Required Result: Field engineers must be able to send and receive e-mail with employees at the headquarters operation.
- Optional Desired Result: The wireless technology chosen should be as cheap as possible. It should also be secure from electronic eavesdropping.
- Proposed Solution: The network manager recommends leasing a cellular link from GTE MobilNet for $2,500 a month, plus air time charges and encryption fees. Which results does this solution deliver? Explain.
- The proposed solution delivers the required result and both of the optional desired results.
- The proposed solution delivers the required results and only one of the two optional desired results.
- The proposed solution delivers the required results but neither of the optional desired results.
- The proposed solution does not deliver the required result.
- (10 points) On an Ethernet coaxial network, all users share the medium. Bob has just moved to your group (and network) from manufacturing, and he brought his ancient 80286 10MHz PC/AT with him. Bob’s system includes an equally decrepit NE 1000 Ethernet NIC. Knowing the overall performance of the network will be influenced by the speed of Bob’s computer, which of the following solutions makes the most sense, assuming you can’t replace his PC with a newer, faster model? Justify your choice.
- Replace the 8-bit NE 1000 with a 16-bit NE 2000.
- Replace the 8-bit NE 1000 with a 32-bit NE 3200 EISA card because EISA is backward-compatible with ISA, and you can enjoy the extra performance boost.
- Run a dedicated cable from the server to Bob’s machine and put him on his own network segment. That way, his laggard performance won’t affect anybody else.
- Buy a 32-bit PCI bus-mastering card and get Bob’s machine moving on the network as fast as possible.
- (10 points) You’ve just bought a fully featured new Pentium MMX PC. When you bring the machine into your test lab, you discover that all the interrupts your PCI Ethernet card can use (IRQ3, IRQ5, IRQ10, IRQ11, and IRQ15) are already taken by other devices, but IRQs 12 and 7 are available. Which of the following strategies is the most likely to produce a machine with a working network connection that preserves as much of the existing hardware as possible? Explain your answer in full.
- Read the manuals for the other adapters in the machine. If any of them use one of the IRQs the NIC needs and you can switch them to one of the open IRQs, your problem is solved.
- Remove all nonessential adapters and install the NIC. Then use whatever IRQs are available to install as many of the other adapters as you get working.
- Buy a PC card interface for your computer’s expansion chassis. Use a PC card NIC instead of the PCI Ethernet card you originally planned to use.
- Buy a serial-attached network interface. This will allow you to plug the network into your serial port and not have to change any of your other configurations. Who cares if the top speed of your serial port is 115Kbps?