Need suggestion on IP SLA on DC and DR scenario

[Raghavendra Rai]

Dear Experts,

I need to build a back-up MPLS connectivity for an existing MPLS link connecting multiple locations to DC and DR as shown in the diagram.

ISP-1: Existing link

ISP-2 New connectivity.

In ISP-1 CPE to PE Routing is static and for some reason it can not be changed to dynamic routing.

ISP-1 has to be primary link it can not be secondary.

As of now for failover between primary and secondary, I can think of configuring IPSLA only. Can you please suggest?

In case of DC and DR scenario can anyone please suggest how IPSLA can be configured? If there is any better solution please suggest..

Tks,

Ragahvendra

[Vasilii Mikhailovskii]

Hello.

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[Raghavendra Rai]

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[Vasilii Mikhailovskii]

Hello.

Sure you may use ip sla (on spokes) to track ISP1 reachability and failover to ISP2 in case of any issue.

At the same time this would work ONLY if you have dynamic routing between DC and ISP1!

If only statics are available for DC, then I would suggest to build a mesh of GRE tunnels (mGRE) over both ISPs and run EIGRP over tunnels.

PS: it's also possible to run BGP over ISP clouds, but it would make things slightly more complicated.

[Raghavendra Rai]

Thanks Vasilii,

In case of DC and DR Scenario should I create two tunnels from each spoke on each ISP?

2 tunnel to DC from 2 different ISP+ 2 tunnels to DR from 2 different ISP from all locations?

[Vasilii Mikhailovskii]

Hello.

The diagram you provided, makes me think, that you want 2 tunnels per spoke for DC and 2 tunnel per spoke for DR.

As I mentioned before - if you need direct spoke-2-spoke connectivity, then you need mGRE (otherwise spokes will be communicating with each other via DC/DR only).

PS:it's also possible to configure tunnels on DC/DR as mGRE and as p2p GRE on spokes (would be beneficial if you want to avoid DC/DR reconfiguration whenever you add/move/rdecommission spokes).