Redundant frame network?

I'm looking for advice on how to set up a redundant network to overcome most network failures. I have 2 host sites that each have a point-to-point to a vendors mainframe via 56k. Site 1h and 2h have a 128k frame between them and each have another interface to the internet. All routing is set via static routes right now. This is were it get complicated. Site 1h has 4r remote sites connected via 128k frame relay and site 2h has 2r remote site connected by 128k as well. I need to find the best way to keep every branch running no matter which circuit dies. I can get a PVC from the 4r over to 2h and get PVC's from the 2r over to 1h. I'm open to any suggestions on design and routing protocol (i.e. eigrp/ospf or rip).

h=host r=remote

Reply to
Michael Letchworth
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I can't afford to design your network for free, but I can give you some free advice about where to start:

You need three things to get useful redundancy:

1 - A mechanism for detecting when a failure has occurred.

2 - A mechanism for doing something about detected failures.

3 - An implementation where that something will work when needed.

Number 1 & 2 are pretty well covered by typical routing protocols (although there are exceptions, particularly for 1). Number 3 is where most people make mistakes, ignoring single points of failue or not testing backup links until they are needed.

If you have the time, read my book "High Availability Networking with Cisco" cover to cover. Then recognize that I barely scratch the surface of all the considerations which go into a high availability network, and only cover the networking aspects, there are also application requirements, for which you should read "Blueprints for High Availability" by Marcus and Stern.

Focus on backing up what is most likely to fail (the normal tendency is to focus on what is easy to back up, or if using sales consultants, what is most profitable to back up). Physical diversity of long distance links tends to have the highest cost, highest pain, and highest payoff; but don't overlook infrastructure basics such as power and HVAC. As always, your mileage WILL vary, and your network WILL fail, all you can influence is how often and for how long.

If your network is really important and there is real money riding on eliminating downtime, consider hiring a competent consultant to help you out. Just be sure the consultant is competent, there are plenty of wannabes out there. (Hint: if they start by telling you the solution before asking you what your problem is, grab your wallet and find a real consultant rather than a sales droid).

Good luck and have fun!

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