IP Routing Question

[Brian Densmore]

Monty,

> 
>   To keep it fairly simple, suppose I have the address space 
> 123.0.0.0/8
> to play with, and I'm starting with 4 subnets [123.x.0.0/16, 
> where x is
> subnet 1..4], and leaving open the option to extend this 
> later.  I want a
> hybrid mesh-star topology with each gateway cross-linked 
> directly to the
> other gateways.  This gives me a total of 10 subnets, the 
> extra 6 being
> the two-NIC links used to route traffic to the various Real 
> Subnets.  Is
> there any reason why these Nominal Subnets can't use private 
> IP space? For illustrative purposes, and to canonicalize the 
> addressing, the NICs
> connecting subnets x and y (where x<y) could be 10.x.y.x and 
> 10.x.y.y on
> /30 subnets.  [Not that you'd likely want to do this in Real 
> Life, but it makes the example reasonably easy to follow].
> 
   I see nothing wrong with your proposed configuration. In fact other than
the fact that you have a star topology, we do exactly that sort of thing
with one of our customers (partly because the customer has two disparate
networks plus two IT service providers and three admin locations). We have
four private IP spaces, one public, and one VPN. Fortunately for me, I don't
need to administer the network ... it is extremely difficult to troubleshoot
such a network, but doable.

> The only thing I can see this causing problems with is
> traceroute, ...

Traceroute works with our system, although we are not using a star topology,
so some routes go through several networks to get there (single point of
failure, as opposed to your solution -albeit with different addresses).  

Brian