Fundamentals of IP Version 6

Question 1

When IPV4 uses octet as a name for its 8 digit binary number, how does IPV6 name its 4 digit numbers?

Answer 1

Quartet

Question 2

IPv6 has 128-binary number, it abbreviates to 8 quartets of four____ digits.

Answer 2

hexadecimal

Question 3

The two steps to abbreviate a IPv6 address are:

Answer 3

1. leave all zeros of the first three digit out in the quartet. If last digit of quartet is zero, leave as it is. DO NOT LEAVE OUT TRAILING 0s. ie. FE00 can’t not be abbreviated as FE0.
2. Find any string of two or MORE consecutive quartets of all hex 0s, and replace that set of quartets with a double colon ::. You can ONLY use the double colon once in an address. Use for the longest string of consecutive zeros.

Question 4

How many bits are in the prefix of a IPv6 address?

Answer 4

128

Question 5

How to determine the subnet ID in IPv6(simple)?

Answer 5

/64 = prefix; 64/4=16 number of prefix bits; write down all hex number in the first 16 bits of the IPv6 address and everything else is 0.

Question 6

We can usually end a IPv6 subnet ID with double _______.

Answer 6

colon ::

Question 7

Identify the following type’s first hex digits:

1. global Unicast:
2. Unique Local
3. Multicast
4. Link-Local

Answer 7

1. 2 or 3, all not otherwise reserved(today)
2. FD
3. FF
4. FE80

Question 8

Global unicast of IPv6 is similar to ________ of IPv4.

Answer 8

Public address

Question 9

When IPv4 has three parts of an address: Network, subnet(borrowed from host) and hosts bits, the IPv6 also has three part that is correlated to the IPv4:

Answer 9

Global Routing Prefix(P Bits), Subnet(S Bits), and Interface ID(I Bits).

Question 10

How may S Bits does a IPv6 has if there are 64 I bits and 32 P bits?

Answer 10

32 S Bits (S = 128-I-P)

Question 11

What is the reason not to use an easy remembering prefix for IPv6 is that_______-.

Answer 11

it will cost a painful merging process when a company buys out another company and their use similar private addresses.

Question 12

What are some characteristics of Link-Local Address?

Answer 12

1. They are unicast IPv6 addresses routes within a local subnet.
2. They are automatically generated and they are used for next-hop address for IPv6 routes.

Question 13

By definition, the first 10 bits of link-local address must match the prefix_____, which means that the first three hex digits will be either______________.

Answer 13

FE80::/10;

FE8, FE9, FEA or FEB

Question 14

Define when multicast address that has organization-local scope(as oppose to link-local scope).

Answer 14

A multicast that routes beyond its local subnet into other subnets in the enterprise network.

Question 15

While IPv4 uses ARP functions, IPv6 uses______.

Answer 15

Neighbor Discovery Protocol (NDP).

Question 16

Mask as to IPv4 when _____ as to IPv6.

Answer 16

Prefix Length

Question 17

What are the four addresses needed in a IPv6 host setting?

Answer 17

Interface Unicast IPv6 Address, Associated Prefix Length, Default Router IPv6 Address(link-local), DNS Server IPv6 Addresses.

Question 18

What is the function of SLAAC(Stateless Address Auto Configuration) in NDP?

Answer 18

The host uses NDP messages to learn the first part of its address, plus the prefix length.

Question 19

What are the main functions of NDP?

Answer 19

SLAAC: learn its address and prefix length; Router Discovery, Duplicate Address Detection; Neighbor MAC Discovery.

Question 20

How does a IPv6 host find its default router?

Answer 20

Using Router Solicitation(RS) and Router Advertisement(RA). RS to sent to all IPv6 routers local scope multicast address FF02::2 so routers can identify themselves. RA, sent by the router, list facts about the router with unicast when RS received. IF unsolicited, the router will send multicast to all IPv6 hosts using FF02::1.

Question 21

How does Neighbor Solicitation and Neighbor Advertisement differ than RS and RA?

Answer 21

NS and NA ask and render information(IPv6 Addresses and MAC Addresses) among hosts while RS and RA refer between a host and a router.

Question 22

What is the DAD check?

Answer 22

Duplicate Address Detection, use by a host to see if the address acquiring has been used by other host. Using NS as “reply if you are 2001:DB8:1111:1::11. Another host’s NA: that’s me.

Question 23

What is one of the major difference between DHCPv6 and DHCP?

Answer 23

DHCPv6 does not supply default router information to the client. Hosts need to use NDP RS and RA to identify the default router.

Question 24

stateful DHCPv4 and DHCPv6 can be a lot of work for the IT to configure on the DHCP server side, what is a solution?

Answer 24

SLAAC (Stateless Address Auto Configuration), which doesn’t require a stateful server to assign or lease the IP addresses and does not require IT staff to preconfigure data per subnet.

Question 25

SLAAC hosts learns part of the address ______ and then makes up the rest of its own IPv6 address.

Answer 25

the prefix

Question 26

What are the steps for a host to use SLAAC to get its host IPv6 Address?

Answer 26

1. learn IPv6 prefix using NDP RS/RA
2. Choose its own IPv6 address by making up the interface ID value to follow the just learned prefix.
3. Before using it, use DAD to make sure no other hosts are using it.

Question 27

The Stateless DHCP is use to identify the DNS server but it has less work to do compares to stateful DHCP because:

Answer 27

It needs simple configuration, needs no per-subnet configuration, and has no need to track state information about DHCP leases.

Question 28

How does router adds IPv6 routes?

Answer 28

1. The configuration of IPv6 on working interfaces(connected and local routes)
2. The direct configuration of a static route (static routes)
3. The configuration of a routing protocol, like OSPFv3, on the routers that share the same data link(dynamic routes, in this case, OSPF routes).

Question 29

How does router adds IPv6 routes?

Answer 29

1. The configuration of IPv6 on working interfaces(connected and local routes)
2. The direct configuration of a static route (static routes)
3. The configuration of a routing protocol, like OSPFv3, on the routers that share the same data link(dynamic routes, in this case, OSPF routes).

Question 30

What are the rules for connected and local routes?

Answer 30

1. Routers create IPv6 routes based each unicast IPv6 address on an interface as configured with the “ipv6 address” command. : the router creates a route for the subnet (connected route); the router creates a host route (/128 prefix length) for the router IPv6 address.
2. Routers do not create routes based on the link-local addresses associated with the interface.
3. Routers remove the connected and local routes for an interface if the interface fails, and re-adds these routes when the interface is again in a working up/up state.