These two commands seems similar when I configure a DMVPN Spoke. What is the difference?

interface Tunnel1
 ip address
 no ip redirects
 **ip nhrp map**
 ip nhrp map multicast
 ip nhrp network-id 1
 **ip nhrp nhs**
 tunnel source FastEthernet0/0
 tunnel mode gre multipoint

1 Answer 1


Thanks to PacketLife.net:

Assuming router foo is configured as the Next-Hop Server, has a physical interface with IP address, and a tunnel interface with IP address whose source is the interface, then

ip nhrp nhs designates router foo as the Next-Hop Server.

ip nhrp map statically maps to foo's physical address.

Basically, it's a chicken-and-the-egg problem. Normally, you'd query the NHS for a tunnel endpoint's physical address, but you need to know the NHS's physical address in order to query it. Thus, the static mapping.

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