Regarding routing protocols
 

HI,
could a cisco router, use multiple ROUTING protocols i.e. EIGRP & OSPF, & if yes then that router would communicate with a non cisco router thru OSPF and a cisco router using EIGRP...
If this is right then let me knoe....

A Cisco router can use multiple routing protocols. Whether it can communicate with non-cisco routers using one protocol or the other I'm not sure.

When using multiple routing protocols, the protocol with the lowest administrative cost is added to the routing table. So the route will either be EIGRP OR OSPF but not both. This if from my limited understanding of Cisco routers.

Should work.

EIGRP is Ciso propietry which is why I am assuming you want to use OSPF to talk to the *nix box. This is actually quite common and would make the Cisoc a "border router".

Here's some info:

http://www.cisco.com/warp/public/103/1.html

Read the bit on route tagging carefully as that's what I think you are trying to do.