Please Please Please Help!!!!!!

Divine

OK i am a third year I.T. with Multimedia student and one of my Subjects this year is Networking TCP/IP and all that other stuff. Now normally my grades are good at college and i find the work enjoyable but i seriously cannot get my head around this Networking crap.

Now my problem is that i have a major exam coming up soon and i got some past exam papers and have gone through them and have not dont too bad overall. However there are some question that i just cannot get no matter how hard i try.

This might sound like a major sob story but i dont wan to fail my third year over some crappy subject so im posting some of the questions here and id really appreciate any help with them.


Regards,



1 (a) Calculate the time (in seconds) it takes to transfer a 7
megabyte file across a network that operates at 14.4
Kbps, T1, 10Mbps, OC1, 100Mbps, and 2.4 Gbps.
(Show all calculations in your answer)

(b) Exactly how many class A, B and C networks exist?
Exactly how many hosts can a network in each class
have? Be careful to allow for broadcast as well as
class D and E addresses.

(c) Your companies have the following networks with a
requirement to sub-net as listed in the below table.
Network Number of sub-networks required
103.0.0.0 2
204.18.58.0 7
183.40.0.0 4
1. Calculate how many bits you require to implement
your sub-netting scheme.
2. List your sub-net mask.
3. List the range of hosts on each sub-net.
4. List the broadcast address on each sub-net.
5. Calculate the number of addresses you lose
through implementing your sub-net scheme

2
(a) Describe how traceroute determines the intermediate
routers between a source and destination. Use an
example that contains 8 routers to illustrate your
answer. What is the difference between the Microsoft
and Unix implementation?

(b) The diskless workstations from one vendor use
RARP to obtain their IP addresses, but always
assume the response comes from the workstation’s
file server. The diskless machine then tries to obtain
a boot image from that server. If it does not receive a
response, the workstation enters an infinite loop
broadcasting boot requests. Explain how adding a
backup RARP server to such a configuration can
cause the network to become congested with
broadcasts. Hint think of power failures.(Use
illustrations where appropriate in your answer, 80
words minimum)


3
(a) What is the single greatest advantage of having the IP
checksum cover only the datagram header and not
the data? What is the disadvantage? (60 words
minimum)

(b) Argue that fragments should have small non-standard
headers. Illustrate your answers with your proposed
new header format. (Use illustrations where
appropriate in your answer, 100 words minimum)


PLease please please help :-)

fractal

You aint stuck on em all are you?

Anything _in particular_ you're stuck on and I'll give you a hand..

Karoma

hehe. TI student? ;-)

Karoma

Originally posted by Divine

1 (a) Calculate the time (in seconds) it takes to transfer a 7
megabyte file across a network that operates at 14.4
Kbps, T1, 10Mbps, OC1, 100Mbps, and 2.4 Gbps.
(Show all calculations in your answer)

(different ways of doing it but..)
for each connection speed: convert the 7megabyte file into the relevant size (ie MB -> Kb (keep an eye on case b != B, and so on.also,to be sure: make a note of it on paper) and then calculate (divide)

(b) Exactly how many class A, B and C networks exist?
Exactly how many hosts can a network in each class
have? Be careful to allow for broadcast as well as
class D and E addresses.

google, books,etc. (calc from number of host bits -v- network bits...)

(c) -- you need a good tutorial on this: from the college or google...

the rest: google or comer's

Most of these questions were taken from Comer's Internetworking
With TCP/IP -- available from the library,amazon (cheap).. and the answers (some) on the WWW

seamus

As Fractal said, pick the questions from above, and tell us exactly what you don't understand about them. If you have absolutely no idea where to begin, then say that. If you have a rough idea of what to say, but aren't sure, then say that.

No-one will answer the questions, since you won't learn anything that way.

ando

just read a book and learn how to answer them. coming on here asking us to answer your questions is a bit sad

Divine

Yeah but you see im not really looking to understand them that much considering that once this year is over i will never be having anything to do with Networking again so all i really want is some help with the questions.

Then i can proceed to learn them off thus passing my exam. Thanks for the help there Karoma, il just try one of them and will you tell me if im right or not.

Cheers!!


7MB = 7000kb

7000/14.4 = 486.1

486/60 = 8.1 minutes.....is that right or am i just way off?

---

Fractal id really like a hand with part C of question 1, i know these play a major mart in TCP/IP routing so if you could clarify them somewhat for me id really appreciate it

Thanks everyone!

spongebob

Files are measured in Bytes Kb means Kilobyte
Data speeds are measured in Bits Kb means KiloBit

8 Bits in a byte
8 Bits in a byte
8 Bits in a byte
8 Bits in a byte
8 Bits in a byte
8 Bits in a byte
8 Bits in a byte
8 Bits in a byte
8 Bits in a byte

7Mb file =7000000 Bytes or 56000000 bits

a 14400 modem will d/l that in 3888 seconds or 64.81 minutes
a 100000000 network will d/l that in .56 seconds.

M

fatherdougalmag

Commonly overlooked but
1k = 1024 bytes
1MB = 1024k = 1,048,576 bytes = 8,388,608 bits
7MB = 58720256 bits

1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB
1024 bytes in 1k - 1024k in a MB



http://www.convert-me.com/en/convert/computer and set sig digs to 7

Capt'n Midnight

ROFL 8192b in a KB

Of course I take it you can ignore the overhead. (though the level of some of the other questions suggests you should at least mention that you are aware of it)

In the real world the full bandwidth is not available to data. Each packet of data also has destination and source address and port addresses and checksums etc. Then there are the ack nowledgement packets to confirm that each packet has been recieved. (Also on the data link will be other packets where machines identify each other and for general maintaninence ARP / DNS / WINS / SNMP etc. )

So the answer you get will be less than real world data speeds (unless the link uses compression..)

Rabies

Originally posted by Karoma
hehe. TI student? ;-)

i'm sure we could dig out our answer from last year to most of those questions but i'm know i'm too lazy don't know about karoma.

Most of these questions were taken from Comer's Internetworking
With TCP/IP -- available from the library,amazon (cheap).. and the answers (some) on the WWW

some of the questions can be found on the internet along with the some short answers, then just elaborate on it.

Karoma

too lazy.
i got penalised when we did 'em for including overhead and rount trip.. fecker.
they're pish easy. the rest (theory) is on the web and in the book.