[e2e] use of MAC addresses

[Detlef Bosau]

Fahad Dogar wrote:


> I think this is one very valid answer to my question.  My question was
> not on whether we should do away with MAC addresses. As has been
> rightly pointed out in this thread there is no need to do this ---
> both from cost and efficiency point of view. I was interested in
> knowing whether we can do this in 'theory' i.e. if we can identify an
> interface by an IP address then in theory we should be able to reach
> that interface without requiring any other form of identification.

I think, Joe correctly refered to the MAC layer and MAC protocol.

> You have right mentioned the need for another address during the phase
> when the IP address is not assigned (DHCP). Any other alternative

DHCP is one very special issue.

IP is an abstraction. IP based internetworks are an abstraction. They 
_hide_ any subnetwork specific technology / requirement from upper layers.

Nevertheless, the subnetworks themselves exist. Wether we have a Token 
Bus system which frequently solicits new terminals to join the network 
or whether we have a PSTN which needs (phone) numbers for dialing and 
reaching a peer - either way, subnetworks exist and so do their 
requirements.

It is something _hidden_ by IP and it is something taken care of by 
subnetworks. From a top down perpective, the only function provided by a 
packet switching network is to convey a packet from terminal A to 
terminal B. And you don´t care about how this is achieved. In fact, the 
capability of conveying a packet from terminal A to terminal B in a 
subnetwork is the only requirement for this subnetwork to be part of an 
internetwork.

Unfortunately, this argument might not work the other way round.
Being capable of having an IP address migth be not sufficient for a 
subnetwork to work.

Detlef





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