On 8/20/2011 17:38, clipka wrote:
> Nonsense. There's no connection-oriented networking in the classic Ethernet,

What machines does the broadcast address connect to? Guess what? That's what 
they're connected to.

That's the sort of connection I'm talking about, which is important for 
management and maintenance and routing. Indeed, the lack of management 
features is exactly why people went to star topology ethernet, precisely 
because ethernet, like IP, wasn't really connection oriented in that sense, 
and when something broke (like beaconing or disconnecting), it was 
impossible to isolate and diagnose.

Now, of course, IP treats each ethernet network as something separate from 
the routers that link to other ethernet networks. IP isn't really needed if 
you run over ethernet without routers.

I'll grant that IP also runs over non-CO networks like alohanet. Other than 
that, there's a pretty clear idea of whether you're connected or not to 
adjacent machines. IP also isn't needed if you run your network over alohanet.

> You /might/ consider the current route through the internet a kind of
> IP-layer connection,

I believe you misread me. I'm saying IP layers non-connection-oriented on 
top of network connections. I don't need to explain how IP can be 
interpreted as connection-oriented, because I'm saying IP makes 
connection-oriented networks non-connection-oriented.

> but given that it can change even from packet to
> packet, and the packets can reach the receiver in arbitrary order, I'd call
> that pretty far-fetched.

But in practice, it generally doesn't. That's why things like path MTU work. 
However, you're reading me in the wrong direction. IP takes something 
connection-oriented (dial-up, star topology ethernet, etc) and turns it into 
non-connection-oriented. And then layers on top of IP are almost invariably 
used to turn it back into a connection-oriented conversation. The most 
commonly used reason to not have something connection-oriented is that IP 
drops packets and you can't reliably know it happened. I.e., the reason to 
use UPD instead of TCP is often that the underlying IP has made the 
connection unreliable (non-reservation, etc) compared to something that's 
actually connection-oriented.

-- 
Darren New, San Diego CA, USA (PST)
   How come I never get only one kudo?

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