On 8/19/2011 8:49, Invisible wrote:
> OK. Is that for legacy reasons, or because ATM is actually good at something?

ATM is a lot less legacy than IP is. Yes, of course it's actually good at 
something.

> "Yeah, IP really sucks, except for being really flexible." Yes, because
> flexibility is a really sucky thing to have.

I didn't say that. I said it sacrifices other things in preference to being 
flexible. There's no resource allocation. There's no way to force a 
particular route thru the network (well, there is, but nobody actually 
implemented it in their switches), the addressing sucks for large networks, 
the address space (in IPv4 at least) is exceedingly limited, remote 
management of hardware is extremely limited, there's no access control, 
admission control, or decent rate regulation other than actually dropping 
packets, etc etc etc.

Heck, it doesn't even do roaming, which cell phones have been managing for 
10 years.

>> It's both inefficient in transmission and extremely
>> difficult to manage well.
>
> In what way?

See above. Every packet has the full source and destination address, and 
there's no information anywhere about the physical network.

> The entire population of Kansas is only 2 million people. The IP address
> space is 4 *thousand* million unique addresses. So unless each person has a
> thousand telephone numbers, you don't have a problem.

Yeah, I realized I mentally screwed that up, and corrected it in the next 
message. :-)

And remember, tho, that IP needs an address for every interface, not for 
every endpoint. So if I make a phone call from my phone to the switch to 
your switch to your phone, that would take 4 IP addresses using IP.

>> But it's everywhere, for the same reason that C is everywhere:
>> It's so limited you can layer it on top of pretty much any underlying
>> transport.
>
> I still don't see the problem. Then again, IP is the only thing I've seen
> that can handle more than 100 nodes at once...

You... are unfamiliar with phone lines?  A *small* phone switch handles a 
half a million end users and hundreds of thousands of trunk lines.

>> For example, one of my colleagues was making fun of ISO's CMIP for being
>> connection-oriented, because having trouble getting a connection is one
>> of the most common reasons you'd use SNMP. I said "they just dedicate a
>> physical connection to it. The smallest bundle going into any switch has
>> 900 physical pairs, and usually closer to hundreds of thousands." At
>> this point, the student was enlightened.
>
> I'm not though.

Let's just say that managing and programming hardware is rather different 
depending on whether you're dealing with a lossy packet-switched network or 
a connection-oriented network to which you can dedicate actual physical 
connections for programming and management. Mocking configuration of the 
latter because it would work poorly over the former is missing the point.

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

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