Urgent Help for some questions

Need some urgent help here with some questions

1)Why 48-bit Ethernet address is assigned, when we have IP addresses for each machine?

2)Discuss whether the modem and the codec are functional inverses (i.e., could an inverted modem function as a codec, or vice versa)?

3)A broadcast network is one in which a transmission from any attached station is received by all other attached stations over a shared medium. Examples are a bus topology local area network, such as Ethernet, and a wireless radio network. Discuss the need or lack of need for a network layer (OSI layer 3) in a broadcast network.

4)
a)How is the Channel access problem resolved in Token Ring Network?

b)How are the Acknowledgements handled in a Token Ring Network?


i hereby say thks first

hmm are we doing your homework for you ?

1. You use ethernet addresses AND ip addresses because your hardware doesnt speak IP, it speaks ethernet.. read about the OSI layers for a longer description.

2. --- eh ?

3. -- You need to tell each station who the packet is actually meant for

4. -- By stealing the remote.. actually by passing around a token, whoever has it gets to talk...

5. -- Nobody remembers

You're welcome

hi...hmmm homeworks...missed them but don't liked them...hehehe

anyway:

1. sahihr is right... www.faqs.org/rfcs/rfc826.html

2. i believe that the modem and codec are not inversely the same..although they have the same function, and that is to convert something...the difference lies on what they convert... a modem, as far as i know, converts an analog signal from a telephone line to a digital signal enough for the computer to understand (1s and 0s or binary) in the same manner the modem converts a digital signal to an analog one, that could be transmitted over the copper wire since digital signals won't last that long when transmitted; or simply put, a modem is an ADC and a DAC at the same time. as for the codec (coder - decoder)..as i've learned through electronics communications, these are some ways and means on how to transfer information between two or more communicating party. and a codec is sometimes used to generate the signals that are wanted for either transmission or reception but it does not changes the state of the signal...what i mean is that if a codec is used to alter a signal, the signal's properties could change (ex. phase and orientation) but its state of being remains unchanged. so if its a digital signal it would remain an digital signal. usually a codec is used on a communication setup...specifically in digital communications...

3. a broadcast network is as you've said a x'mission from any station which is received by all stations. there is a need for the network layer in the OSI model in a broadcast network since data in a network describe above goes to all nodes, but not all nodes requested that data. only the requesting node would accept the transmitted data. so how does the transferred data knows that it has the right node? it is by the Network layer of the OSI model that makes this possible otherwise, ther would be a lot of unwanted data given to each node.

4.as for questions for number 4...refer to the link

www.cisco.com/univercd/cc/td/doc/cisintw...tokenrng.htm#xtocid5


hope that this helps...

Thanks alot man to both sahirh and jhun for the help
actually those questions are a few of the questions from my homework ya , i try to find the answer but fail
thks again