Exam 300-730 topic 1 question 7 discussion

The question is asking what commands you would use to migrate from Phase 2 to Phase 3. Disabling EIGRP next hop self is one of the requirements for phase 3.

d is correct since this would sent all spoke traffic always to the hub. This is only ok for Phase 2

DE is correct

To migrate from DMVPN Phase 2 to Phase 3 with EIGRP, you should disable EIGRP next-hop-self on the hub. In DMVPN Phase 3, the spoke routers directly exchange routing information, including EIGRP updates, without going through the hub. Disabling EIGRP next-hop-self on the hub ensures that it doesn't modify the next-hop IP address in the EIGRP updates it sends to the spoke routers. This allows the spoke routers to use their own routing table to determine the next-hop for EIGRP updates.

In the link below it is explained much better https://community.cisco.com/t5/routing/dmvpn-troubleshooting/td-p/3931201

Answer correct are C and E https://networkingjournalblog.wordpress.com/2017/05/04/dmvpn-configuration-phase-3/ #ip nhrp redirect: this command informs the spokes that spoke-to-spoke communication can in fact be had directly and there is no need to traverse the hub. All it does is trigger the spoke NHRP resolution request. Disable EIGRP next-hop-self on the hub: EIGRP next-hop-self is a feature that causes the hub to advertise its own IP address as the next hop for traffic destined for other spokes. When migrating from DM Phase 2 to Phase 3, this feature should be disabled on the hub to allow spoke-to-spoke communication without going through the hub.

D and E are correct. Remember Phase 3 EIGRP in terms of configuration requires a slight modification to the existing configuration from phase 2, and a couple additional commands at the hub and spokes, but otherwise it is very much the same. The additional command needed at the hub is "ip nhrp redirect". For phase 3 to be really successful, the command "no ip next-hop-self eigrp x "from phase 2 must be revoked for EIGRP. Forgetting to enable next-hop-self on the hub will give the impression that phase 3 is working when it is not. Phase 3: disable “no ip next-hop-self eigrp x” and enable “ip nhrp redirect.” R1(config)# int tun 0 R1(config-if)#ip next-hop-self eigrp 100 R1(config-if)#ip nhrp redirect

Correct answer is DE

D and E https://ine.com/blog/2008-12-23-dmvpn-phase-3

D and E. Next Hop Self Enabled, cause redirection is done using NHRP.

Answer is D and E. DMVPN disables the EIRGP next-hop-self with "no ip next-hop-self eigrp xxx" in DMVPN phase 2, and to go from Phase 2 to 3 you need use the NHRP protocol, and again enable EIRGP next-hop-self with "ip next-hop-self eigrp 134" under the tunnel interface https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_conn_dmvpn/configuration/15-mt/sec-conn-dmvpn-15-mt-book/sec-conn-dmvpn-dmvpn.html#GUID-BF561439-BCC0-4AAF-80D9-1F7876CB7B81