How to configure redundant CVG in layer 3

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  • Updated 10 months ago
Hey guys ..looking for some guidance/experience from anyone that has setup redundant CVG gateways (layer 3) .. I have a pretty good handle on the VPN configuration but how is the routing/failover performed? Do I have to use dynamic routing (ospf) to get this to work correctly?

Also any experiences that anyone has had would be greatly appreciated? (ie does it work smoothly and effectivly?) Thanks in advance for any assistance.
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Dave Allaby

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Posted 10 months ago

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Andrew Garcia, Official Rep

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Yes, you must support dynamic routing via OSPF or RIPv2 in your network to set up redundant CVGs.

The solution is designed with the intent that the redundant CVGs are deployed in different parts of the network (different data centers, for instance), not in parallel in the same data center. Both CVGs are actually active, just weighted differently. If you deploy them in parallel in the same place, therefore, you run the risk of creating an asynchronous route back to the BR.
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Dave Allaby

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Thanks for the reply Andrew.. When you say weighted, is server 1 preferred route until it is down? in other words there is no 'load balancing' of tunnels correct?

Also would I need to adjust ospf cost at all?
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Andrew Garcia, Official Rep

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From the BR's perspective, the primary CVG will always have a lower route metric. The BR will not share the load between tunnels, but will instead govern the decision on route cost.

FYI, the BR only shares it's route info with the CVG via an HTTP based routing mechanism. The CVG shares the route table with the BR network with the rest of your network via OSPF/RIPv2.

As long as the CVGs reside in different L3, it should work fine without need for adjust OSPF costs.
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Dave Allaby

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Thanks again for the great explanation..