Ch31-Implementing IPv6 on Hosts

Question 1

A protocol that is part of the IPv6 protocol suite, used to discover and exchange information about devices on the same subnet. In particular, it replaces the IPv4 ARP protocol

Answer 1

Neighbor Discovery Protocol (NDP)

Question 2

A message defined by the IPv6 Neighbor Discovery Protocol, used by routers to announce their willingness to act as an IPv6 router on a link.

Answer 2

Router Advertisement (RA)

Question 3

A message defined by the IPv6 Neighbor Discovery Protocol, used to ask any routers on the link to reply, identifying the router, plus other configuration settings (prefix and prefix length)

Answer 3

Router Solicitation (RS)

Question 4

A message defined by the IPv6 Neighbor Discovery Protocol, used to declare to other neighbors a host’s MAC address.

Answer 4

Neighbor Advertisement (NA)

Question 5

A message defined by the IPv6 Neighbor Discovery Protocol, used to ask a neighbor to reply with a message listing the neighbor’s MAC address

Answer 5

Neighbor Solicitation (NS)

Question 6

A feature of IPv6 in which a host or router can be assigned an IPv6 unicast address without the need for a stateful DHCP server

Answer 6

Stateless Address Autoconfiguration (SLAAC)

Question 7

A term used in IPv6 to refer to how hosts first check whether another host is using a unicast address before the hosts begins using that address

Answer 7

Duplicate Address Detection (DAD)

Question 8

The IPv6 equivalent of the IPv4 ARP table, listing IPv6 addresses of hosts on the same link, along with their matching MAC addresses, as typically learned using Neighbor Discovery Protocol

Answer 8

ipv6 neighbor table

Question 9

A term used in IPv6, describing a DHCP service that doesn’t lease IPv6 addresses to clients, or track their IPv6 addresses or client identifiers, but may provide other useful information, such as the clients DNS server settings

Answer 9

stateless DHCPv6

Question 10

A term used in IPv6, describing a DHCP service that keeps track of which clients have been lease associated IPv6 addresses

Answer 10

stateful DHCPv6

Question 11

Command reference: Interface subcommand that enables the IPv6 DHCP relay agent

Answer 11

ipv6 dhcp relay destination address

Question 12

Command reference: Lists the router’s IPv6 neighbor table

Answer 12

show ipv6 neighbors

Question 13

Command reference: Lists any neighboring routers that advertised themselves via an NDP RA message

Answer 13

show ipv6 routers

Question 14

What command produced the following output:

Answer 14

show ipv6 neighbors

Question 15

What command is used to enable a router interface to act as a DHCP relay agent?

Answer 15

ipv6 dhcp relay destination dhcpv6-server-address

Question 16

List four functions in which NDP plays a major role

Answer 16

Router discovery

SLAAC

Neighbor MAC discovery (solicitation/like ARP)

Duplicate address detection

Question 17

Router solicitation messages are sent to this multicast address

Answer 17

all-routers multicast FF02:2

Question 18

Unsolictited router advertisement messages (RA) are sent to this multicast address

Answer 18

all-nodes, FF02::1

Question 19

What addresses are solicited router advertisement messages are sent to?

Answer 19

Unicast address of solicitor

all-nodes FF02::1

Question 20

An IPv6 host needs to send data to a host on the same link, but does not know that hosts link-layer (MAC) address. IPv4 hosts would ARP for that information. An IPv6 host will instead send a neighbor solicitation message (NS) instead. To what local-scope address will the NS message be sent?

Answer 20

The solicited node multicast address of the target (FF02::1:FFxx:xxxx, where xx:xxxx are the last 6 hex digits of the destination unicast address).

Question 21

An IPv6 host sends a router solicitation to locate it’s default router. What will be returned in the router advertisement?

Answer 21

Link-local address of the default router for the link

Question 22

How does a SLAAC host determine its prefix and prefix length?

Answer 22

Solicit router; router advertisement contains the prefix/prefix length for the link.

Question 23

What particular information would a client learn from a stateful DHCP server? What would it need to learn from some other source?

Answer 23

Stateful DHCPv6:

Unicast address

prefix/prefix length

DNS server

NDP process:

default router

Question 24

Describe the events in the SLAAC process

Answer 24

1. learn link prefix via NDP RS+RA
2. calculate interface ID (EUI-64, random)
3. Perform DAD via NS+NA prior to using address