[comp.protocols.iso] X.25 packet vs pt-to-pt data networks

green@cbnewse.att.com (david.bruce.green) (03/28/91)

If you compare the costs of a point to point circuit
between two locations against the cost of connecting
both ends to a public packet network, the pt-to-pt
circuit is almost always cheaper.
In fact, from several comparisons I've made using
real customer data, full mesh connectivity between
multiple locations doesn't become cheaper with packet
networks until the number of locations gets to around
five or more.  HOWEVER, when a problem develops with
your connections, you're pretty much on your own to
shoot the trouble with a pt-to-pt network.  A good
packet network vendor (AT&T's APS comes to mind) will 
act as your agent in dealing with local access companies,
and partner in trouble shooting all the way back to your
equipment (protocol analyzers, etc).  Sometimes that's
worth the extra cost.

Same is true for dial-up access to hosts.  Network
transport for 800 or SDN type services can be cheaper,
but maintaining a mux and modem pool can be a hassle.  
Plugging into a packet network and letting the vendor 
worry about those things is much easier albeit more
costly.

				Dave Green
				ihlpl!dbg