On Fri, Dec 4, 2009 at 1:57 AM, Joel M. Halpern <[email protected]> wrote:
> As for what I want to identify, I tend to think that the identifier should
> correspond not to the physical node, but to the logical stack construct. A
> logical set of protocol machinery, stacked from the network layer up. A
> physical machine may have multiple of these. And in some cases, a single
> one of these may be operating across physical boundaries, if the coupling
> works right.
>
This is a model I could understand. In old terms, which many of this
community might not like, this 'logical stack' id is once used to be call
'node address'. And this exactly 'node address' is used to identify that
logical stack construct (from network layer up through transport up to the
app layer) AND, what is more important, is also used for 'routing'. Stating
again, one id, called 'node address' is used both for identifying a node AND
routing.
So, in this model, there's no two separate things like ID and Locator.
Whereas... the 'physical address', or in Internet terms 'PoA address', is in
fact the Layer 2 address, or MAC address.
So, you
- identify a (logical and physical) node by a 'node address'
- do you L3 routing based on this 'node address'
- in passing through sub-network or L2 network, you map this 'node
address' to 'L2 or MAC' address.
The flaw that the Internet had was to regard the IP address as the PoA
address. No. IP address should be the 'node address'. That is, if you have
to choose one of the two roles that IP address was thought to assume, i.e.
ID and Locator, it should be the 'ID' part we have to preserve. The name
'ID', though, is not the correct one, since in this (new but in fact old)
model, this 'ID' is also used as L2 routing. Therefore, the correct name
should be 'node address'.
Then what to do with the PoA part of IP address we gave up above? That PoA
part will exactly be the role of sub-network or L2 (or MAC) address.
So, to me, IP address is fine as it is now, only that I use IP address as
pure L3 'node address'. Or put it more correctly, 'sub-network independent
internetworking' node address.
Whereas the physical address you mentioned is to me, either
- subnetwork address or
- L2 address or
- MAC address
depending on what underlying service is available to my 'internetworking'
sublayer.
The whole confusion of the Internet has ever started to define IP address as
PoA address. No, it should be 'node address'. And there's no such thing as
PoA address, but subnetwork or L2 address.
I don't propose to throw away IP address. Rather keep it but use it only in
the context of the 'node address' (which term this community has associated
with ID).
Mostly, I like your idea of separation. Only that, your ID should not be a
new creation, but the IP address be used as ID, or more exactly, node
address. And leave everything else to the underlying layer's job or
property.
--
Regards,
DY
http://cnu.kr/~dykim
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