lesson 3: ipv6 fundamentals

Internet Protocol version 6 (IPv6) Fundamentals

Mahmmoud Mahdi

IPv6 Vs. IPv4

IPv4 4.3 billion unique addresses

IPv6 3.4 undecillion (3.4 ×10³ )⁸ 340,282,366,920,938,463,463,374,607,431,768,

211,456 340 undecillion, 282 decillion, 366 nonillion,

920 octillion, 938 septillion, 463 sextillion, 463 quintillion, 374 quadrillion, 607 trillion, 431 billion, 768 million, 211 thousand, 456

IPv4 Limitations

The limitations of IPv4 are: Limited number of addresses Routing difficult to manage Host configuration is complex No built in security Limited Quality of Service

IPv6 Improvements

Improvements in IPv6 include: Built in QoS (Quality Of Service) More efficient routing Simpler host configuration Better prioritized delivery support Redesigned headers for efficient processing and

extensibility Built-in security▪ IP security through the use of IPSec is an integral part of IPv6,

whereas it was an optional feature under IPv4. Increased address space▪ providing 2128 (about 340 billion) unique addresses.

IPv6 Address Space

The IPv6 address space is: 128 bits address, or 16 bytes for addressing of

four hexadecimal digits, separated by colons 8 groups of 4 Hex characters▪ using eight groups Displayed in hexadecimal▪ Characters: 0-9, A-F

Allows routing flexibility

IPv6 Vs. IPv4

An example of an IPv4 IP address 192 .168.1.101

An example of an IPv6 IP address 2001:0DB8:85A3:08D3:1319:8A2E:0370:7334 3FFE:0501:0008: 0000:0260: 97FF:FE40:EFAB▪ 3FFE:501:8:0:260:97FF:FE40:EFAB▪ 3FFE:501:8::260:97FF:FE40:EFAB

IPv6 Address Format

Decimal-Hex-Binary conversion

Decimal 0 1 2 3 4 5 6 7

Hex 0 1 2 3 4 5 6 7

Binary 0000 0001 0010 0011 0100 0101 0110 0111

Decimal 8 9 10 11 12 13 14 15

Hex 8 9 A B C D E F

Binary 1000 1001 1010 1011 1100 1101 1110 1111

IPv6 Address Syntax

IPv6 addresses are: Can use zero compression▪ Eliminate consecutive zeros “: :”▪ “Leading”

Use a prefix to define the network portion of address rather than a subnet mask.

Two Parts▪ 64 bit network component▪ 64 bit host component

IPv6 Address Shortcuts

:0: stands for :0000: You can omit preceding 0s in any 16-bit word.

:DB8: and :0DB8: are equivalent. A series of sequential zeroes the address can be

shortened to use a single zero in each group, or else the entire grouping can be represented using a double colon (: :). 2001:0000:0000:0000:0000:0000:0000:7334 = 2001:0:0:0:0:0:0:7334 = 2001::7334

:: can be used only once in an address IPv6 Loopback Is ::1

IPv6 Address Shortcuts Example

The address 2001:0DB8:0000:0000:1234:0000:A9FE:133E

Compress :0000: into :0: 2001:0DB8:0000:0000:1234:0:A9FE:133E

Eliminate preceding zeros: 2001:DB8:0000:0000:1234:0:A9FE:133E

Use the special variable shortcut for multiple 0s: 2001:DB8::1234:0:A9FE:133E

IPv6 Address Assignment

Do you subnet IPv6? If you are given 32 bits of network from your ISP, you

have 96 bits to work with. If you use some of the 96 bits to route within your

network infrastructure, then you are subnetting. Client Configuration

Manual▪ Required for routers

Automatically▪ From routers▪ DHCPv6 servers

IPv6 Address Types

There are three types of addresses in IPv6:

Type Description

Anycast Equivalent to IPv4 unicast

Unicast Additional unicast address types

Multicast Equivalent to IPv4 multicast

IPv6 Address Types(1) Anycast

Anycast Visually similar to global Many destination hosts with the same address▪ Address assigned to multiple devices.

Finds nearest based on router cost▪ When an anycast packet is sent, it is delivered to one

of the devices, usually the closest one.

IPv6 Address Types (2) Unicast

Unicast A unicast packet uniquely identifies an interface

of an IPv6 device. Unicast addresses come in several types:▪ Global unicast address▪ Link-Local Address▪ Unique Local Address

IPv6 Address Types (2) Types of Unicast

Global Addresses (GAs) Equivalent of public addresses in IPv4. Address space is defined as 2000::/3 ▪ High level bits 001▪ First block value between 2000-3FFF

The structure of GAs


Link-Local Address (LLAs) Similar to APIPA addresses Self-configured, non-routable Provides automatic communication on local

subnet Defined as FE80:: /10.

The structure of LLAs:


Unique-Local Addresses (ULAs) Similar to Private addresses▪ They are not expected to be routable on the global

Internet. Defined as FC00 or FD00::/7

The structure of ULAs:

IPv6 Address Types (3) Multicast

Multicast address One-to-Many communication packets. Multicast packets are identifiable by their first byte. Defined as FF00::/8 In the second byte shown (the “00” of FF00), the second 0 is what’s called the scope. ▪ Interface-local is 01, and link-local is 02 ▪ FF01:: is an interface-local multicast.

There are several well-known multicast addresses Ex: if you want to send a packet to all nodes in the link-local

scope, ▪ You send the packet to FF02::1 (FF02:0:0:0:0:0:0:1). ▪ The all-routers multicast address is FF02::2

IPv6 Address Space Known Prefixes and Addresses

Address Prefix Scope of Use

2000:: /3 Global unicast space prefix

FE80:: /10 Link-local address prefix

FC00:: /7 Unique local unicast prefix

FF00:: /8 Multicast prefix

2001:DB8:: /32 Global unicast prefix use for documentation

::1 - ::/1 Reserved local loopback address

2001:0000: /32 Teredo prefix (discussed later in this chapter)

2002:: /16 6to4 prefix (discussed later in this chapter)

IPv6 Transition Technologies

New Header Format Not supported by current IPv4 routers

Router Upgrade Required Before Moving To IPv6

IPv6 Integration/Migration

Dual stack Running both IPv4 and IPv6 on the same network Utilizing the IPv4 address space for devices using only IPv4

addresses and utilizing the IPv6 address space for devices using IPv6 addresses

Tunneling Using an encapsulation scheme for transporting one address

space inside another Address translation

Using a higher-level application to transparently change one address type (IPv4 or IPv6) to the other so end devices are unaware one address space is talking to another


IPv6 Dual Stack


IPv6 Tunneling Several tunneling mechanisms for tunneling

IPv6 through the IPv4 address space. Used for unicast IPv6 communication across an

IPv4 infrastructure. They include the following:▪ Intra-Site Automatic Tunnel Addressing Protocol

(ISATAP)▪ 6to4▪ Teredo

IPv6 Tunneling

Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) Allows IPv6 and IPv4 hosts to communicate through a ISATAP

router▪ By performing a type of address translation between IPv4 and IPv6.

Intended for use inside a private network. Enabled by default in Windows Server 2008.▪ “Tunnel Adapter Local Area Connection* 8”

IPv4 embedded in IPv6▪ e.g., FE80::5EFE:192.168.1.5

All ISATAP clients receive an address for an ISATAP interface. The format of an ISATAP address is as follows:▪ [64bits of prefix] [32bits indicating ISATAP] [32bits IPv4 Address]

ISATAP routers allows IPv4-only and IPv6-only hosts to communicate with each other

IPv6 Tunneling

6to4 Tunnels IPv6 traffic over IPv4 through 6to4 routers. Similar to ISATAP, but designed for public network

(Internet)▪ Intended to be used on the Internets.

IPv4 is encapsulated in IPv6 Requires 6to4 routers▪ Router has public IP

2002:/16 prefix▪ Router advertises 2002: subnet ::/64▪ hosts auto configure 6to4 address

6to4 allows IPv6-only hosts to communicate over the Internet

IPv6 Tunneling

Toredo Similar to 6 to4 but unnecessary to upgrade edge routers. Toredo is used (Preferred) only when no other IPv6

translation is available. Allows clients behind an IPv4 NAT to use IPv6 on the

Internet Enabled by default in Windows Server 2008.▪ “Tunnel Adapter Local Area Connection* 9”

2001::/32 prefix

32 prefix Teredo IPv4 Internet ID64 64

Hex

Neighbor Discovery

Neighbor Discovery is a set of messages and processes that determine relationships between neighboring nodes.

Some of the ND functions are: Router discovery Prefix discovery Parameter discovery Address auto-configuration Address resolution Duplicate address detection

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lesson 3: ipv6 fundamentals

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