CIS656_105
Homework for 10/24/2001.

Read Comer I pp 177 - 195. (Ch 11).

Log on to a Unix system and read 
man nslookup  and 
man traceroute .

Recommended: Also  make a hardcopy and take it home.

(A good place to find help with Unix in the lab in GITC 2305. Much of
the time there are TAs available).

By using ping, check that you can not send a an IP packet with total 
size 2^(16) = 65536 bytes (65508 + 8 + 20), but that within NJIT 
you can send any size smaller packets.

By doing pings to 195.129.111.8 I found that packets with 16356 data
bytes (16356 + 8 + 20 = 16384 = 2^(14) total size, incl ICMP and IP
headers), or smaller, often returned, while larger packets never
returned.

Check that you find the same result.

Check whether you can find other destinations that have similar cutoff 
behavior.

Give what you think is the most plausible explanation for this phenomena.

Use nslookup to find the name of computer   195.129.111.8   .

Use traceroute and nslookup to find the names of as many as you can of
the routers in between a (one) computer in New Jersey and a (one)
computer across an ocean. (Use 195.129.111.8 if you do not have a more
interesting candidate).

---

For Oct 31 I plan to ask a question along the following lines:

Log on to a Unix system. Find its name and it's IP adress. Find another 
computer with almost the same address, therefore almost certainly on
the same network.
Hint: If you are in GITC 2305, do 
nslookup afs1 , nslookup afs2, etc., nslookup afs36. 
(Not all: just a few is enough).

(An alternative is to find the address of your computer and try ``close by'' 
addresses).

By using ping with various packet sizes, estimate the (usable) bandwidth 
of the network connecting the two computers. 

Teun Ott.