Not Accepted After September 27Th

TDC 460

Homework #1

Autumn 2010

Not Accepted After September 27th

1. Match the functions in the table with the OSI layer and TCP/IP layer that performs them. If you cannot find a function in the lecture notes you may have to Google it. Be careful – some terms may sound generic but are actually specific terms used in a particular model.

Function OSI Layer TCP/IP Layer

data compression

definition of the electrical characteristics of a signal

dialog management

electronic mail

encryption and decryption

error detection

establishing and releasing a session

establishing and releasing a connection

file transfers

format conversions

multiplexing

routing

switching

token passing

2. Consider a CSMA/CD LAN with two workstations at the ends of a 1 km connection and with a data rate of 100 Mbps.

a. What is the time to send a frame of 1500 bits to another station, measured from the beginning of transmission to the end of reception? (Propagation time plus data transfer time) Assume a propagation speed of two-thirds the speed of light (copper wire).

b. If two stations begin to transmit at exactly the same time, their packets will collide. If each transmitting station monitors the bus during transmission, how long before it notices this collision, in seconds? How many bits will be transmitted during this time?

3. The address 43:7B:6C:DE:10:00 has been shown as the source address in an Ethernet frame. The receiver has discarded the frame. Why?

4. An Ethernet MAC sublayer receives 1510 bytes of data from the upper layer. Can the data be encapsulated in one frame? If not, how many frames need to be sent? What is the size of the data in each frame?

5. What is the ratio of useful data to the entire packet for the smallest Ethernet frame? What is the ratio for the largest frame?