On 8/19/2011 8:16, Invisible wrote:
> OK. So exchange to exchange links and stuff?

That, carrying text messages sometimes, control backplane, DOCSIS, DSL, etc 
etc etc. Anything where high-speed packet switching with connection-oriented 
service makes more sense. Any place where the actual physical connections 
aren't changing very fast, an underlying connection-oriented protocol is not 
uncommon and usually much more robust, managable, and efficient.  *Then* you 
layer IP on top, in order to give you a layer of virtual switching. (And 
indeed, network switches go through a lot of effort to try to turn IP 
networks into connection-oriented networks, with stuff like caching of 
recently seen IP addresses, path MTU protocols, etc.

I.e., ATM is used over fiber (usually in turn over SONET) wherever in *your* 
house you are using ethernet.

Honestly, IP is a pretty sucky and limited technology, except for its 
flexibility. It's both inefficient in transmission and extremely difficult 
to manage well. You couldn't possibly use it internal to the phone company 
for routing or addressing. (For example, one area code (aka "city code") in 
the USA supports more phone numbers than all of IPv4.) 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.

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.

>>> Aside from that, the report isn't well written at all. The tone is very,
>>> very informal. Like, if you imagine being given a topic, and just
>>> monologuing about it to your friend off the top of your head,
>>
>> I'm not sure I need to *imagine* that as such...
>
> Nice to know I've *always* sucked at report writing. :-P

Wrong tense. ;-) Read the last sentence I quoted, then start over on your 
message again. ;-)

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

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