[c-nsp] Backup/redundant internet connection

[James Jun]

> The
> fiber and DSL line would terminate on two seperate OSPF capable on the ISP
> side (all in the same OSPF backbone). The customer has VPN as well as mail
> and a web site. They want their IP address to remain the same regardless
> of
> which internet connection is being used. I have a diagram demonstrating a
> proposal I've made to my boss but I am wondering if there is a simpler
> method - http://www.vci.net/Images/net.gif

Though I recognize that it is a managed router by your team, you might find
it better to scale for a various situations by moving customer interconnects
iBGP/BGP; but this is a hotly debated topic between enterprise and -SP, so
YMMV.

> 
>     I've tried a similar method using a single router (not two routers as
> shown in the diagram) that I couldn't get to work. This alternate method
> used a loopback interface that would perform the NAT functions. The
> problem
> was I couldn't get the outbound traffic to be NAT'd. It went directly to
> the
> physical outbound interface.

How is your NAT config done?  A simple setup like below typically works fine
in sourcing NAT to loop0. (where 101 is acl defining what to nat and what to
not):

ip nat inside source list 101 interface Loopback0 overload


regards,
james