newbie ques : why does lan (ethernet) require ip address ?

According to TCP/IP model LAN (ethernet) works in network access layer (physical and data link in OSI) and IP address are in Internet layer (Network in OSI).....

But while setting a LAN we need IP address (considering a simple LAN with no Internet connection).

No part of ethernet goes in the internet layer but still we have to use IP addresses...

WHY?

Re: newbie ques : why does lan (ethernet) require ip address

i think (not sure) that we still need it, cause for a sending host to be able to send a certain msg, it needs the mac (physical) address of the destination host. and the only way for that is the ARP (Address Resolution Protocol), and this protocol uses the IP address of the destination to get the mac address.

do you know the answer?

If you are asking if the IP address is needed from
the physical point of view then the answer is NOT.
It is not needed. The old netware and even microsoft
internal networks using a different protocols than
TCP/IP. There is even another protocol I used a long
time ago(NOS) that was a packet network. Anyone
can have their own protocol and use as they please.
Only that now days the dominant protocol is TCP/IP
and it is used almost exclusively in all software even
if the card is not going to be connected, because will
use an address that will not interfere with other address
in internet since it will be internal.

Re: newbie ques : why does lan (ethernet) require ip address

u definitely need IP addresses. if u see ur LAN card, after it get installed, it install TCP/IP protocol. so u need IP addresses.


Naveed

Re: newbie ques : why does lan (ethernet) require ip address

This is simple ,let me explain from real life.In your apartment your door no is D1 and your neighbors door no is D2.These are MAC addresses.So when you want to say something to your neighbor its easy for you but PC do not know where it is .PC only knows the door number which is D2.So we uses IP and Subnet masks in our LANs.When your PC(10.0.0.4) wants to send message to another PC(10.0.0.6) first communicate with all PCs in your lan and asks What is the MAC address of PC with the IP address 10.0.0.6.Later it learns the MAC addressof the PC. So if there is a pc without IP address can not communicate with the others.

yes u can not work with out an IP even if you are not connected to the internet ,let say that u have a large Network with many no of Routers in it,and many subnetworks ,if one PC in certain subnetwork wants to communicate with another PC in another subnetwork ,here u need to send the MAC and IP addresses of the destination,while the destination MAC when passing the Router is always the next hop not the final destination MAC of the PC u want to communicate with from this point u can not communicate with the other PCs in the other subnetwork
another point that what ever the model is,the data unit within the layer must understand the upper layers protocol,while we have only one standard in both whether u use the internet or not ,here is also another reason for use of the IP while not connecting to the internet,wish the message could be arrived