NHRP Question

Ryan82

I have read some Cisco docs online but am still having a little trouble wrapping my head around the necessity of using NHRP.

We have a setup where multiple remote access users connect via GRE tunnels back to the main site which is running multipoint gre.

Why is it needed?

FattyAcid

Ryan82 wrote: »

I have read some Cisco docs online but am still having a little trouble wrapping my head around the necessity of using NHRP.

We have a setup where multiple remote access users connect via GRE tunnels back to the main site which is running multipoint gre.

Why is it needed?

I don't recall NHRP being on the CCNP, but anyway...

1) NHRP is used to dynamically determine the IP addresses of the spokes/remote sites, so you don't have to configure them on the hub router (or the spokes assuming fully meshed). This useful when you have dynamically assigned IP addresses for the spokes/remote sites (DSL, Cable modem).

2) The hub router's GRE and IPSec (if you're using it) configuration is simplified because its sort of learning the necessary configuration via NHRP.

3) When you add a new spoke/remote site to the network, NHRP keeps you from having to add its IP address or perform any GRE/IPSec configuration on the hub (or spokes if you're doing fully meshed).

Make sense?