Single IPSec Tunnel to Multiple Hub routers in DMVPN?

[smooth_cruiser]

Hi:

Trying to understand how exactly does a single tunnel on a spoke connect to multiple hub routers in a DMVPN environment?

I see a config with multiple NHRP statements:

int t0

ip nhrp map multicast 172.16.0.1

ip nhrp map multicast 172.16.0.2

ip nhrp map 10.0.0.1 172.16.0.1

ip nhrp map 10.0.0.2 172.16.0.2

ip nhrp nhs 10.0.0.1

ip nhrp nhs 10.0.0.2

Also see crypto keyring and crypto isakmp profile configured. Is this a requirement for such a scenario?

Is there a good doc/link on cco that explains this in detail?

Thanks,

SC

[Todd Pula]

This doc is a good place to start when trying to learn the fundamentals of DMVPN.

http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/DMVPDG.html

[smooth_cruiser]

Hi Todd:

Thank you very much.

That was a great doc.

I guess I just need to understand when to use the crypto key-ring and crypto isakmp profile features.

Under what kind of circumstance would one use this feature?

What is the benefit of using this feature - either in a Dual-DMVPN with a Sigle Head-End Tier architecture or a Dual-DMVPN with a Dual Head-End Tier architecture?

Thank you.

SC