Declan
Bialowas

Hassan
Peyravi

Computer
Communications Network

1/27/2018

Homework #1

1.There
are two reasons for using layered protocols which is that it breaks up the
problem in question smaller and more manageable pieces, as well as that
protocols can be changed more easily without affecting higher or lower layers
involved.

One
possible disadvantage of using layered protocols is the matter of redundancy
and overall lower performance comparatively.

 

2.
Message M

Layer 1— M + h

Layer 2— M + h + h = M + 2h

Layer 3— M + 2h + h = M + 3h

Layer n— M + (n – 1)h + h = M + n x h

  # of header bytes with n-layers and h bytes
per header=(n x h). The fraction of the network bandwidth filled with headers
is (n x h)/(M+(n x h)).

 

3.
The main difference between TCP and UDP would have to be the fact UDP is
connectionless while TCP is specifically connection oriented.

 

 

4.

Campus                                   Address
       Average Time       
Distance

Stanford
University               
stanford.edu         89  ms                2,518 miles

University
of California, L.A.  ucla.edu
            65 ms
             2,386
miles

University
of Utah
                 utah.edu
              48
ms               1,747 miles

Princeton
University
              princeton.edu
      34.6 ms            428 miles

Michigan
State University     msu.edu
               
21 ms              255 miles

            The findings indeed point to the
correlation between ping time and physical distance

 

5.            The image is 1024 x 768 x 3 bytes or 2,359,296 bytes. This is 18,874,368 bits. Over a 56-kbs(56,000 bits/sec) modem channel, it takes  18,874,368/56,000=337.042 sec. Over a 1-mbs(1,000,000 bits/sec) cable modem, it takes 18,874,368/1,000,000=18.874 sec. Over a 10-mbs(10,000,000 bits/sec) Ethernet, it takes 18,874,368/10,000,000=1.887 sec. Over a 100-mbs(100,000,000 bits/sec) Ethernet, it takes 18,874,368/100,000,000=0.189 sec.