IPv6

IANA Global Unicast Address

2000::/3

Neighbor Unreachability Detection

Accomplished two ways: Nodes listen for ACKs If no ACK is received a neighbor solicitation is sent to confirm next-hop

IPv6 loopback address

0:0:0:0:0:0:0:1, also expressed as ::1, or ::1/128

An IPv6 address is how many bits long?

128 (8 groups of 16 bits, 0:0:0:0:0:0:0:0)

How big is the IPv6 address pool?

340 trillion trillion trillion OR 3.4x10^38

Each 16 bit group of an IPv6 address is written as?

4 Hexadecimal digits

IPv6 Header is how many bytes?

40

IPv6 header - Hop limit...

8 bit integer is decremented by 1 each time the packet is forwarded

Convert Binary IPv6 to Hexadecimal

Break it into 8 blocks of 16 bits Split each block into 4 segments (32 total) Write down the Hex for each segment

IPv6 link-local address

Derived from the MAC address of the interface and the FE80::/10 prefix

all-devices multicast address

FF02::/1

all-routers multicast address

FF02::/2

osfp-routers multicast address

FF02::/5

ripv2-routers multicast address

FF02::/9

eigrp-routers multicast address

FF02::/A

Global unicast IPv6 address breakdown

First 3 bits 001 45 bits for global routing prefix 16 bits for subnet ID Last 64 bits for Interface ID

Multicast address breakdown

First 8 Indicator bits (FF) 4 scope bits indicate reach (1 = Node local, 2 = link-local, 5 = Site local, E = Global) Last 32 bits refers to a multicast group

Binary 0000

Hex 0

Binary 0001

Hex 1

Binary 0010

Hex 2

Binary 0011

Hex 3

Binary 0100

Hex 4

Binary 0101

Hex 5

Binary 0110

Hex 6

Binary 0111

Hex 7

Binary 1000

Hex 8

Binary 1001

Hex 9

Binary 1010

Hex A

Binary 1011

Hex B

Binary 1100

Hex C

Binary 1101

Hex D

An IPv6 Unicast address...

Identifies a single interface

An IPv6 Multicast addresses...

Identify groups of interfaces, packets are delivered to all interfaces in the group

An IPv6 Anycast addresses...

Identify groups of interfaces, packets are sent to the nearest interface in the group

unique local unicast address

In TCP/IP Version 6, an address used to identify a specific site within a large organization. It can work on multiple links within the same organization. The address is a hybrid between a global unicast address that works on the Internet and a link-local unicast address that works on only one link. also called unique local address (ULa).

What does the "manage bit" do?

Indicates whether or not the host should use DHCP to obtain additional addresses

What does the "other bit" do?

Indicates whether or not the host should use DHCP to obtain other information

IPv6 header - Flow label...

Intended to label sequences of packets that require special handling

How can an IPv6 address be shortened?

Leading zeroes are removed and consecutive sections of zeroes are replaced with colons (::) but it may only be used once per address

MEUI-64

Modified Extended Unique Identifier-64

IPv6 does not use ARP but?

NDP - Neighbor Discovery Protocol

The first 64 bits of an IPv6 address are the?

Network address bits, also called the prefix (or subnet)

SLAAC Phases

Phase 1 - Link local address (Neighbor solicitation process) Phase 2 - Global address (Router solicitation process)

/64 prefixes are the ________ common subnet you will use in IPv6

Smallest

SLAAC

Stateless Address Auto Configuration

EUI-64 Format

Take the interfaces 48 bit MAC address and add FFFE directly in the middle. Invert the 7th bit. So a MAC address of 00-11-22-33-44-55 would become 0211.22FF.FE33.4455.

What happens after a link local address is generated?

The host verifies its link local address by sending out a neighbor solicitation message, if it is unused by another host it then sends out an ICMPv6 router solicitation message to determine if there are any IPv6 enabled routers

IPv6 header - Traffic class...

This 8 bit field is used to mark packets for differentiated service (CoS, QoS)

IPv6 header - Version...

This field is 4 bits and contains the version number of the IP packet

Binary 1110

Hex E

Binary 1111

Hex F

6 IPv6 Extension Headers

Hop-by-Hop Options Destination Options Routing Fragment Authentication Encapsulating Security Payload

The last 64 bits of an IPv6 address are the?

Host address bits

Unique Local Unicast Address Type

fc00::/7, these addresses are not routable on the global Internet, or private address space

Multicast Prefix

ff00::/8

Link Local Address Type

ff80::/10

IPv6 header - Next header...

8 bit selector which identifies the type of header that immediately follows this header

IPv6 header - Payload length...

8 bits long and specifies the length of everything in the packet that follows this header

Unspecified Address Type

::/128, refers to the host when the host does not know its own address

IPv4 Mapped Address Type

::ffff:0:0/96, /96 prefix leaves 32 bits, exactly enough to hold an embedded IPv4 address

Router Discovery

Hosts send router solicitation messages to the multicast address and an available router responds with a router advertisement (Routers periodically send out these advertisements)

Neighbor Discovery

IPv6 hosts communicate their link layer addresses using neighbor solicitation and neighbor advertisement messages

Neighbor Discovery Process

This process uses ICMP messages to determine the link layer address of a neighbor on the same network

IPv6 Address Types

Unicast, Anycast, Multicast

Redirects

Used by routers to inform hosts of a better path to destination