[c-nsp] Help with topology changes....

[Richard Golodner]

	We have recently seen our Ethernet interfaces shut down with the
introduction of some new network topology. For a number of years we have
been using IP unnumbered on our RFC 1918 Frame Links to simplify our
configuration at our branch offices. These frame links provide a private,
unmeshed network between our branches and the corporate headquarters. 
	In the fall of 2004 we introduced DSL access to the internet at our
branch offices. In order to protect against any threats we have added a
hardware based firewall at each location. In order to get these units to
route properly we were told by the manufacturer to add a gateway of last
resort routing statement to each branch router.  For example: ip route
0.0.0.0 192.168.9.2  Since doing this we have seen our Ethernet interfaces
shut down on occasion due to what seems to be excessive overhead. I also see
traffic from my other subnets in the firewall logs, which I am sure is a
result of the last resort statement. A simple reload brings the network back
to life, but I would like to know if there exists a better configuration
than the one we are using.
	We are wondering if assigning an IP to the Serial Interface rather
than using IP unnumbered would be better. 
	We are using Cisco 1720 with 48 megs of RAM and our clients are XP
with service pack 2 applied. Any thoughts are greatly appreciated.


						Richard Golodner
						Network Manager
						Aetea Information Technology