Lecture 6. Ipv6 subnetting and ICMP.pdf

Question 1

Why do we need IPv6?

Answer 1

IPv4 is running out of addresses; IPv6 offers a larger 128-bit address space and includes enhancements like simplified headers and improved support for IoT.

Question 2

What is the size of an IPv4 address?

Answer 2

A: 32 bits (2³² ≈ 4.3 billion addresses).

Question 3

What is the size of an IPv6 address?

Answer 3

A: 128 bits.

Question 4

What are the three methods for IPv6 migration?

Answer 4

A:

Dual Stack

Tunneling

Translation (NAT64)

Question 5

What is Dual Stack?

Answer 5

A: Devices run both IPv4 and IPv6 simultaneously.

Question 6

What is Tunneling?

Answer 6

A: Encapsulating IPv6 packets in IPv4 to travel across IPv4 networks.

Question 7

What is NAT64?

Answer 7

A: Allows IPv6 devices to communicate with IPv4 devices using translation.

Question 8

What format is used to write IPv6 addresses?

Answer 8

A: Hexadecimal, as 8 groups of 4 hex digits separated by colons.

Question 9

What is a hextet in IPv6?

Answer 9

A: A 16-bit segment of the address (4 hex digits).

Question 10

What is Rule 1 for compressing IPv6 addresses?

Answer 10

A: Remove leading zeros in each hextet.

Question 11

What is Rule 2 for compressing IPv6 addresses?

Answer 11

A: Replace one group of consecutive zero hextets with “::” (only once).

Question 12

What are the three main types of IPv6 addresses?

Answer 12

A: Unicast, Multicast, Anycast.

Question 13

What is a Unicast address?

Answer 13

A: Identifies a single interface.

Question 14

What is a Multicast address?

Answer 14

A: Sends a packet to multiple devices.

Question 15

What is an Anycast address?

Answer 15

A: Delivered to the nearest device with that address.

Question 16

Does IPv6 support broadcast?

Answer 16

A: No, it uses multicast instead.

Question 17

What is a Global Unicast Address (GUA)?

Answer 17

A: Internet-routable and globally unique.

Question 18

What is a Link-Local Address (LLA)?

Answer 18

A: Used for local link communication; not routable.

Question 19

What is a Unique Local Address (ULA)?

Answer 19

A: Like private IPv4 addresses; not routable on the internet (range fc00::/7).

Question 20

What is the format of an IPv6 GUA?

Answer 20

Global Routing Prefix : Subnet ID : Interface ID

Question 21

How do you statically assign a GUA on a router?

Answer 21

interface g0/0/0
ipv6 address 2001:db8:acad:1::1/64
no shutdown

Question 22

How do you manually assign a Link-Local Address (LLA)?

Answer 22

ipv6 address fe80::1:1 link-local

Question 23

What protocol is used to assign IPv6 GUAs dynamically?

Answer 23

ICMPv6.

Question 24

What are RS and RA messages?

Answer 24

RS (Router Solicitation): Sent by hosts to discover routers.

RA (Router Advertisement): Sent by routers to provide prefix and configuration info.

Question 25

What are the 3 RA methods to configure IPv6 GUA?

Answer 25

1. SLAAC 2. SLAAC + Stateless DHCPv6 3. Stateful DHCPv6

Question 26

What is SLAAC?

Answer 26

A: Device configures itself using RA messages, no DHCP.

Question 27

What is EUI-64?

Answer 27

A: Uses MAC address to create a 64-bit Interface ID by inserting fffe and flipping the 7th bit.

Question 28

How is a dynamic LLA created?

Answer 28

A: Automatically by combining fe80::/10 with an interface ID (EUI-64 or random).

Question 29

What prefix do IPv6 multicast addresses use?

Answer 29

A: ff00::/8.

Question 30

What are two well-known multicast groups?

Answer 30

A: ff02::1 All-nodes group ff02::2 All-routers group

Question 32

How does IPv6 support subnetting?

Answer 32

Using the Subnet ID between the Global Routing Prefix and Interface ID.

Question 33

What is the purpose of ICMP?

Answer 33

A: Provides feedback about IP packet processing issues (e.g., unreachable destinations, timeouts).

Question 34

What are common ICMP message types?

Answer 34

A: Echo Request/Reply (Ping) Destination Unreachable Time Exceeded

Question 35

What are 4 ICMPv6 Neighbor Discovery messages?

Answer 35

A: RS – Router Solicitation RA – Router Advertisement NS – Neighbor Solicitation NA – Neighbor Advertisement

Question 36

What is Duplicate Address Detection (DAD)?

Answer 36

A: Device sends NS with its own address to check if it's already in use.

Question 37

What is the purpose of ping?

Answer 37

A: Tests connectivity using ICMP Echo Request and Reply.

Question 38

What does ping ::1 do?

Answer 38

A: Tests IPv6 stack on the local host (loopback).

Question 39

How is traceroute different from ping?

Answer 39

A: Traceroute shows each hop between source and destination using TTL or Hop Limit.

Question 40

How does traceroute work?

Answer 40

A: Sends packets with increasing TTL values; routers send Time Exceeded messages back.