[omniORB] Addressing/reference problem

[Duncan Grisby]

On Tuesday 21 August, Kevin Bailey wrote:

> We're trying to find a solution to an addressing problem we have
> and were wondering if anyone could help. We have a cluster of
> computers of which only one member is visible to the outside IP
> world. (The cluster uses a 192 subnet.) Nevertheless, there are
> objects on all the computers in the cluster which must be
> reached from the outside world. The requirements are that
> internal traffic be screaming fast while external traffic can be
> slow as a dog.

[...]
> Any ideas would be greatly appreciated!

The best thing is probably to use the NAT approach, combined with
Sai-Lai's recent suggestion here:

  http://www.uk.research.att.com/omniORB/archives/2001-08/0137.html

i.e. give each of the machines in your cluster names which resolve in
DNS to the externally visible machine doing NAT, but resolve
internally to the real addresses of the machines (by putting the names
in /etc/hosts, for example).

To distinguish object references from multiple machines in the cluster
so the NAT machine knows where to forward connections, I can think of
two approaches. The first is to give each machine its own (virtual)
external IP address, all hosted by the NAT machine. The second is to
resolve all the machines' names to the same IP address, and pin down
the port numbers each machine uses for its servers. That way the NAT
machine can translate based on port number.

Cheers,

Duncan.

-- 
 -- Duncan Grisby  \  Research Engineer  --
  -- AT&T Laboratories Cambridge          --
   -- http://www.uk.research.att.com/~dpg1 --