[luau] localhost connections

[Jimen Ching]

On Wed, 20 Mar 2002, whenever wrote:
>layer 3(network) is where your connection happens, layer 2(data link) is
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>where arp is at, would it try to resolve a MAC for the localhost ?

If I remember the OSI model correctly, the connection happens at layer 2,
the data link layer.  Layer 3, the network layer, is where all of the
routing occurs.  Hense, the name 'network'.

I think the OSI model was derived from a connection oriented protocol.
IP is a connection-less protocol.  In the OSI model, when you want to
communicate between hostA and hostB, you ask layer 3 to find a route
between these two hosts.  Then you ask layer 2 to establish a connection.
Then you use layer 1 to make the physical/virtual connection.

This is the reverse of how TCP/IP works.  The connection is established in
TCP, which is above IP.  Also, the 'T' in TCP stands for transport.  But
the transport layer is layer 4 in OSI.  Thus, TCP/IP is a combination of
layer 4, 3 and 2.  TCP provides two services; connection (data link), and
transport.  IP provides the routing (network).  So to map TCP/IP to OSI
accurately, we would need to break TCP into two pieces, and put IP in the
middle.

The more I learn about the TCP/IP stack, the more I think it was poorly
designed.

--jc
--
Jimen Ching (WH6BRR)      jching at flex.com     wh6brr at uhm.ampr.org