Exam 350-501 topic 1 question 92 discussion

correct answer: A. OSPFv3 does not run for IPv4 on FastEthernet0/0 until IPv6 routing is enabled on the router and IPv6 is enabled on interface FastEthernet0/0 To enable OSPFv3 for IPv4, the following config is required: R1(config)#ipv6 unicast-routing R1(config-if)#ipv6 enable R1(config-if)#ospfv3 1 area 1 ipv4

Correct answer is A: OSPFv3 uses IPv6 to discover its neighbors, if not configured there is no neighbor to establish successful negotiation. Even though we only want to configure routing for IPv4, OSPFv3 still uses IPv6 link-local addresses so we have to to enable IPv6 -To use the IPv4 unicast address families (AF) in OSPFv3, you must enable IPv6 on a link, although the link may not be participating in IPv6 unicast AF. -With the OSPFv3 Address Families feature, users may have two processes per interface, but only one process per AF. If the AF is IPv4, an IPv4 address must first be configured on the interface, but IPv6 must be enabled on the interface. -The OSPFv3 address families feature enables both IPv4 and IPv6 unicast traffic to be supported. With this feature, users may have two processes per interface, but only one process per AF. If the IPv4 AF is used, an IPv4 address must first be configured on the interface, but IPv6 must be enabled on the interface. A single IPv4 or IPv6 OSPFv3 process running multiple instances on the same interface is not supported.

Obviously C is wrong. A is correct https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/configuration/15-mt/iro-15-mt-book/ip6-route-ospfv3-add-fam.html

A is correct, if we configure ipv6 unicast-routing globally and IPV6 enable on fas0/0. We can configure an address ipv4 for this interface R1(config)#ipv6 unicast-routing R1(config)#interface Serial0/0/0:0 R1(config-if)#ospfv3 1 ipv4 area 10 % OSPFv3: IPV6 is not enabled on this interface R1(config-if)#ipv6 enable R1(config-if)#do show run int s0/0/0:0 Building configuration... Current configuration : 175 bytes ! interface Serial0/0/0:0 description TESTE ip address 10.0.0.1 255.255.255.252 ipv6 enable end R1(config-if)#ospfv3 1 ipv4 area 10 <----------IT WORKED! R1(config-if)#do show run int s0/0/0:0 Building configuration... Current configuration : 198 bytes ! interface Serial0/0/0:0 description TESTE ip address 10.0.0.1 255.255.255.252 ipv6 enable ospfv3 1 ipv4 area 10 <----------------------- CONFIGURED end

I think its a tricky question, because Option A states: "OSPFv3 does not run for IPv4 on FastEthernet0/0 until IPv6 routing is enabled.." . Even if enable ipv6 globally and under the interface, it still won't work for ipv4.

Correct answer is A. https://networklessons.com/ospf/ospfv3-for-ipv4-configuration

'A' is the correct answer. 'C' is wrong, b/c OSPFv3 supports both IPv4 and IPv6 Unicast address families

correct answer is C btches! ipv6 is enabled globally not on interface, so A is wrong.