Connecting two seperate OSPF networks

[thomuff]

We want to connect two OSPF networks. They have there own area 0s. Site A is acting as an ASP for site B for two critical applications. After that, Site A is an independent network. How would you go about connecte Site B to Site A for this purpose?

thanks

[smif101]

Depending on the size of the network, you could essentialy connect them together via area 0 just like one large network. Or you could create another ospf process on one of the routers connect that to the other area 0 and then redistribute between them. Hopes this helps.

[rais]

Another option is:

If both networks are connecting using a single link, simply put static routes for each network in the other and redistribute that route into OSPF.

HTH

[thomuff]

We are connecting with a T3 and then going to use a GRE over IPSEC Tunnel (Internet) for backup. If I am understanding you. I would put a static route on the routers on both ends and then put redistribute static command in my ospf process.

[deilert]

It sounds easy , prior to doing this I would make certain that there is no overlapping ip ranges .

[thomuff]

We made sure to check that and actually removed the network from our network to prevent the NAT. Also, management thinks we should put a small eigrp network between the two and redistribute and limit by using route maps. What are your thoughts?

[vcjones]

The best way to connect two independent networks which share limited trust with one another is to use BGP, an INTER-domain routing protocol. Unlike OSPF, EIGRP and other INTRA-domain routing protocols, BGP makes no assumptions about trusting the other network (for example, consider route metrics) and easily implements routing policies based on criteria other than route metric.

Using BGP, each network can independently control what it learns from the other network and how what is learned gets redistributed throughout the network.

While you can use EIGRP or static routes to do the job if you only have a single link, as soon as you move to supporting multiple links terminating on multiple routers to eliminate single points of failure, you'll have to start all over again with a protocol which can handle the job. Save yourself a lot of grief and do it right the first time.

Good luck and have fun!

Vincent C Jones

www.networkingunlimited.com