ICND1 IPv4 and IPv6 3

Question 1

Which IPv6 transition mechanism encapsulates IPv6 packets inside IPv4 packets to traverse IPv4 networks?

Accepted Answer

6to4 tunneling

Answer

6to4 tunneling automatically encapsulates IPv6 traffic in IPv4 packets (protocol 41) to cross IPv4-only infrastructure.

Question 2

What is the subnet mask in dotted-decimal notation for a /20 prefix?

Accepted Answer

255.255.240.0

Answer

A /20 means 20 bits are set to 1: the first two octets are 255.255, and the third octet has 4 bits set (11110000) = 240.

Question 3

Which type of IPv6 address is used to identify a set of interfaces, delivering the packet to the nearest one?

Accepted Answer

Anycast

Answer

Anycast addresses are assigned to multiple interfaces; routing delivers packets to the topologically nearest interface in that set.

Question 4

A router interface is configured with IP address 10.1.1.1/30. How many other hosts can be on this subnet?

Accepted Answer

1

Answer

A /30 subnet has 4 addresses total; network=.0, broadcast=.3, so only .1 and .2 are usable — meaning one other host can share this subnet.

Question 5

What is the purpose of the IPv6 Neighbor Discovery Protocol (NDP)?

Accepted Answer

Replace ARP and provide router/prefix discovery

Answer

NDP uses ICMPv6 messages to perform address resolution (replacing ARP), router discovery, and prefix advertisement in IPv6 networks.

(ICND1) Interconnecting Cisco Networking Devices Part 1 Practice Test