Exam 200-105 topic 2 question 48 discussion

The 'no ipv6 ospf hello-interval' and 'no ipv6 ospf dead-interval' are ways to return to the default values. So answer is D.

A. R1(config-if)#ipv6 ospf hello-interval 20 - WRONG, because 20 is not default B. R1(config-if)#ip ospf hello-interval 10 WRONG because "ip"=OSPFv2, not OSPFv3 C. R1(config-if)#ip ospf hello-interval 20 WRONG (see A and B) D. R1(config-if)#no ipv6 ospf hello-interval CORRECT.

Don't overthink the answer is B without a doubt

R1#sh run interface serial 1/0 Building configuration... Current configuration : 193 bytes ! interface Serial1/0 description To_R2 no ip address ip ospf hello-interval 15 ipv6 address 2001:DB8:1:12::1/64 ipv6 ospf 1 area 10 ospfv3 hello-interval 15 serial restart-delay 0 end R1#sh ipv6 os R1#sh ipv6 ospf ne R1#sh ipv6 ospf neighbor R1#sh ipv6 ospf int s1/0 Serial1/0 is up, line protocol is up Link Local Address FE80::A8BB:CCFF:FE00:1000, Interface ID 7 Area 10, Process ID 1, Instance ID 0, Router ID 1.1.1.1 Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT Timer intervals configured, Hello 15, Dead 60, Wait 60, Retransmit 5 Hello due in 00:00:04 Graceful restart helper support enabled Index 1/1/4, flood queue length 0 Next 0x0(0)/0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 0, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) R1#

R1#sh run interface serial 1/0 Building configuration... Current configuration : 222 bytes ! interface Serial1/0 description To_R2 no ip address ip ospf hello-interval 15 ipv6 address 2001:DB8:1:12::1/64 ipv6 ospf 1 area 10 ipv6 ospf hello-interval 20 ospfv3 hello-interval 15 serial restart-delay 0 end R1#

R1# R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int s1/0 R1(config-if)#ospf hello-interval 15 R1(config-if)# R1# R1# R1# R1# R1# R1#conf t *Nov 21 13:36:47.734: %SYS-5-CONFIG_I: Configured from console by console R1#sh run interface serial 1/0 Building configuration... Current configuration : 195 bytes ! interface Serial1/0 description To_R2 no ip address ipv6 address 2001:DB8:1:12::1/64 ipv6 ospf 1 area 10 ipv6 ospf hello-interval 20 ospfv3 hello-interval 15 serial restart-delay 0 end R1#

all command valid R1(config-if)#ospf hello-interval 20 R1(config-if)# R1(config-if)#do sh ipv6 ospf ne R1(config-if)#do sh ipv6 ospf ne OSPFv3 Router with ID (1.1.1.1) (Process ID 1) Neighbor ID Pri State Dead Time Interface ID Interface 2.2.2.2 0 FULL/ - 00:00:22 7 Serial1/0 R1(config-if)# R1(config-if)#do sh ip *Nov 21 13:30:42.287: %OSPFv3-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Serial1/0 from FULL to DOWN, Neighbor Down: Dead timer expired R1(config-if)#do sh ipv6 ospf ne R1(config-if)#ipv6 ospf hello-interval 10 R1(config-if)# *Nov 21 13:31:55.575: %OSPFv3-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Serial1/0 from LOADING to FULL, Loading Done R1(config-if)#do sh ipv6 ospf ne OSPFv3 Router with ID (1.1.1.1) (Process ID 1) Neighbor ID Pri State Dead Time Interface ID Interface 2.2.2.2 0 FULL/ - 00:00:35 7 Serial1/0 R1(config-if)#

And the request it is for ospfv3, so you cannot implement the command ip ospf hello-interval 10, it should be ipv6 ospf. So definitely the answer its D.

It is ambiguous because D is too the correct answer....

Answer is D. #no ipv6 ospf hello-interval will set the R1 hello-interval to default like R2.