資管 lee lesson 3 ipv4/v6 addressing. 資管 lee lesson objectives ipv6/v4 address space ipv6...

資管 Lee <Lesson 3-1>

Lesson 3

IPv4/v6 Addressing


Lesson ObjectivesIPv6/v4 address spaceIPv6 address syntaxUnicast IPv6 addressesMulticast IPv6 addressesAnycast IPv6 addressesIPv6 interface identifiersIPv4 addresses and IPv6 equivalents


IPv4 addressing


4

IP v4 addressingIP 網址

◦32 位元長度，分為四組，每組以 10 進位表示 dec3.dec2.dec1.dec0 ( 如 163.13.4.3)

◦分為網路位址 (Network Address) 與主機位址 (Host Address) 【 Network Number, Host Number 】

◦如 IP 位址為 163.13.4.3 則網路位址 = 163.13.0.0 主機位址 = 0.0.4.3

◦Netmask: 無次網 :255.255.0.0 次網 : 255.255.192.0 ?

Network number host number

32 bits

1111111111111111 0000000000000000

32 bits

Network number host number

IP Netmask

IP Address


IP v4 addressingIPv4 網址分級

00000000

0NetworkNumber Host Number

Class A 1.0.0.0 ~ 126.0.0.0

10

Networ Number Host Number

Class B 128.0.0.0 ~ 191.255.0.0

Networ NumberHost

Number

Class C 192.0.0.0 ~ 223.255.255.0

110

Class D 224.0.0.0 ~ 239.255.255.255

Class E 240.0.0.0 ~ 255.255.255.254

Multicast

Reserved

00000000 00000000 00000000

Default Router 0.0.0.0

01111111 00000000 00000000 00000000

Loopback Address 127.0.0.0

01111111 00000000 00000000 00000001

Local Host 127.0.0.1

1110

11110


保留位址： ◦預定閘門 (Default Router) ： 0.0.0.0 ◦回繞位址 (Loopback Address) ： 127.0.0.0 ◦回繞主機 (Loopback Host) ： 127.0.0.1 ◦廣播位位 (Broadcast Address0

所有主機： 255.255.255.255 某一網路： 164.168.255.255 (164.168.0.0 網路

ID)


Private Networks

Addresses for private network

Class Netids TotalA 10. 1B 172.16 to 172.31 16C 192.68.0 to 192.68.255 256

類別網路位址

主機位址

最多主機數量

可分配的組織數

A 8位元 24位元 16,777,214 128

B 16位元 16位元 65,534 16,384

C 24位元 8位元 254 2,097,152


網址不分級網址不分級 (CIDR, Classless Inter-Domain

Routing)◦ a four-part dotted-decimal address, followed

by a slash, then a number from 0 to 32: 格式 : A.B.C.D/N. 例如 : 163.13.200.98 /16

CIDR subnet 網域 : 163.13.200.98 /16 次網 :163.13.226.98/19 問分成幾個次網 ?

10.10.1.32/27


IPv4 網址使用狀況32 at 2009/1/28


IPv6 addressing


The IPv6 Address Space 128-bit address space

◦ 2128 possible addresses◦ 340,282,366,920,938,463,463,374,607,431,768,211,456

addresses (3.4 x 1038) Why 128 bits

◦ allow multiple levels of hierarchy and flexibility in designing hierarchical addressing and routing

Typical unicast IPv6 address:◦ 64 bits for subnet ID, 64 bits for interface ID

64 位元之 Subnet ID 64 位元之 interface ID


Allocation 前置 (prefix) 所佔比率 (Fraction)

Reversed 0000 0000 1/256 (0000:…/8)

NSAP Allocation 0000 001 1/128 (0200:…/7)

Aggregatable Global Unicast 001 1/8 (2000:…./3, 3000:…./3)

Link-Local Unicast 1111 1110 10 1/1024 (FE80:…./10)

Site-Local Unicast 1111 1110 11 1/1024 (FEC0:…./10)

Multicast 1111 1111 1/256 (FF…./8)


IPv6 Address SyntaxIPv6 Syntax

1) IPv6 address in binary form:00100001110110100000000011010011000000000000000000101111001110110000001010101010000000001111111111111110001010001001110001011010

2) Divided along 16-bit boundaries:0010000111011010 0000000011010011 0000000000000000 00101111001110110000001010101010 0000000011111111 1111111000101000 1001110001011010

3) Each 16-bit block is converted to hexadecimal and delimited with colons:21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A

4) Suppress leading zeros within each 16-bit block:21DA:D3:0:2F3B:2AA:FF:FE28:9C5A


Compressing ZerosSome IPv6 addresses contain long

sequences of zeros◦ A single contiguous sequence of 16-bit blocks set to 0

can be compressed to “::” (double-colon)

Example:◦ FE80:0:0:0:2AA:FF:FE9A:4CA2 FE80::2AA:FF:FE9A:4CA2◦ FF02:0:0:0:0:0:0:2 FF02::2

Cannot use zero compression to include part of a 16-bit block◦ FF02:30:0:0:0:0:0:5 does not become FF02:3::5.


IPv6 Prefixes (CIDR)IPv6 subnets or routes always uses

address/prefix-length notation◦CIDR notation

Examples:◦21DA:D3::/48 for a route◦21DA:D3:0:2F3B::/64 for a subnet

No more dotted decimal subnet masks as in IPv4


Types of IPv6 AddressesUnicast

◦Address of a single interface◦One-to-one delivery to single interface

Multicast◦Address of a set of interfaces◦One-to-many delivery to all interfaces in the

setAnycast

◦Address of a set of interfaces◦One-to-one-of-many delivery to a single

interface in the set that is closestNo more broadcast addresses


Unicast IPv6 Addresses 類別

Aggregatable global unicast addresses

Link-local addressesSite-local addressesSpecial addressesCompatibility addressesNSAP addresses


Aggregatable Global Unicast Addresses

Top-Level Aggregation ID (TLA ID)Next-Level Aggregation ID (NLA ID)Site-Level Aggregation ID (SLA ID)Interface ID

TLA ID Interface ID

13 bits 64 bits

SLA ID

24 bits

001 NLA ID

16 bits

Res

8 bits


Topologies Within Global AddressesPublic TopologySite TopologyInterface ID

TLA ID Interface ID

64 bits

SLA ID001 NLA ID

16 bits

Res

48 bits

Public Topology Site Topology Interface Identifier


Local-Use Unicast Addresses

Link-local addresses ◦Used between on-link neighbors and for

Neighbor DiscoverySite-local addresses

◦Used between nodes in the same site


Link-Local AddressesFormat Prefix 1111 1110 10

◦FE80::/64 prefixUsed for local link only

◦Single subnet, no router◦Address autoconfiguration◦Neighbor Discovery

1111 1110 10 Interface ID

10 bits 64 bits

000 . . . 000

54 bits


Site-Local AddressesFormat Prefix 1111 1110 11

◦FEC0::/48 prefix for siteUsed for local site only

◦Replacement for IPv4 private addresses◦ Intranets not connected to the Internet◦Routers do not forward site-local traffic

outside the site

1111 1110 11 Interface ID

10 bits 64 bits

000 . . . 000

38 bits

Subnet ID

16 bits


Special IPv6 Addresses

Unspecified address◦0:0:0:0:0:0:0:0 or ::◦ Indicate the absence of an address. Typical

used as a source addr. When a unique addr. has not yet been determined.

Loopback address◦0:0:0:0:0:0:0:1 or ::1◦ Identify a loopback interface, enabling a node

to send packets to itself.


Compatibility AddressesIPv4-compatible address

◦0:0:0:0:0:0:w.x.y.z or ::w.x.y.zIPv4-mapped address

◦0:0:0:0:0:FFFF:w.x.y.z or ::FFFF:w.x.y.z6over4 address

◦[64-bit prefix]:0:0 :WWXX:YYZZ (WWXX:YYZZ is the hexadecimal value of w.x.y.z )

6to4 address◦Prefix of 2002:WWXX:YYZZ::/48

ISATAP address◦[64-bit prefix]: 0:5EFE:w.x.y.z


NSAP Addresses

0000001 NSAP-mapped address

7 bits 121 bits

Provide a way of mapping Open System Interconnect (OSI) NSAP (Network Service Access Point)addresses to IPv6 address. [RFC 1888]

NSAP addresses are used in the following OSI-based network technologies:

ATM switched virtual circuit networks X.25 (see ITU-T X.121 for addressing in public data networks) Frame relay IS-IS SDH & SONET networks.

http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode

http://en.wikipedia.org/wiki/X.25

http://en.wikipedia.org/wiki/ITU-T

http://en.wikipedia.org/wiki/X.121

http://en.wikipedia.org/wiki/Frame_relay

http://en.wikipedia.org/wiki/IS-IS

http://en.wikipedia.org/wiki/Synchronous_optical_networking

http://en.wikipedia.org/wiki/SONET


Multicast IPv6 AddressesFlags (4 bits, only last bit is defined, 0 mean permanently, 1,

mean transient)

Scope (4 bits, value: 0, reserved, 1, Node-local scope, 2 Link-local scope, 5 site-local scope, 8 organization-local scope, E Global scope, F Reversed)

Defined multicast addresses◦All-Nodes addresses

FF01::1 (Node Local), FF02::1 (Link Local)

◦All-Routers addresses FF01::2 (Node Local), FF02::2 (Link Local), FF05::2 (Site

Local)

1111 1111 Group ID

8 bits 112 bits

Flags

4 bits

Scope

4 bits


Recommended Multicast IPv6 Addresses

Only 32 bits are used to indicate the Group ID◦Single IPv6 multicast address maps to a

single Ethernet multicast MAC address

1111 1111 Group ID

8 bits 32 bits

Flags

4 bits

Scope

4 bits 80 bits

000 … 000


Solicited-Node Address

Example:◦ Node A link-local is FE80::2AA:FF:FE28:9C5A, listening to

the corresponding solicited-node address FF02::1:FF28:9C5A

Acts as a pseudo-unicast address for very efficient address resolution

Interface ID

64 bits

Unicast prefix

64 bits

FF02:

24 bits

:1:FF0:0:0:0


Anycast IPv6 AddressesNot associated with any prefixSummary and host routes are used to

locate nearest anycast group memberSubnet router anycast address:

Subnet Prefix 000 . . . 000

n bits 128 - n bits


IPv6 Addresses for a HostUnicast addresses:

◦A link-local address for each interface◦Unicast addresses for each interface (site-

local or global addresses)◦A loopback address (::1)

Listening to the Multicast addresses:◦The node-local scope all-nodes multicast

address (FF01::1)◦The link-local scope all-nodes multicast

address (FF02::1)◦The solicited-node address for each unicast

address◦The multicast addresses of joined groups


IPv6 Addresses for a RouterUnicast addresses:

◦ A link-local address for each interface◦ Unicast addresses for each interface◦ Loopback address (::1)

Anycast addresses◦ Subnet-router anycast address◦ Additional anycast addresses (optional)

Listening to the Multicast addresses:◦ The node-local scope all-nodes multicast address (FF01::1)◦ The node-local scope all-routers multicast address (FF01::2)◦ The link-local scope all-nodes multicast address (FF02::1)◦ The link-local scope all-routers multicast address (FF02::2)◦ The site-local scope all-routers multicast address (FF05::2)◦ The solicited-node address for each unicast address◦ The multicast addresses of joined groups


Subnetting the IPv6 Address Space

Subdividing by using high-order bits that do not already have fixed values to create subnetted network prefixes

Two-step process:1. Determine the number of bits to be

used for the subnetting2. Enumerate the new subnetted network

prefixes


Subnetting for NLA IDs

Hexadecimal methodDecimal method

[16-bit prefix]:00 ::

f

s

r


Subnetting for SLA IDs

Hexadecimal methodDecimal method

[48-bit prefix]: ::

f

s

r


IPv6 Interface IdentifiersThe last 64 bits of unicast IPv6

addressesInterface identifier based on:

◦Extended Unique Identifier (EUI)-64 address Either assigned to a network adapter card or derived from IEEE 802

addresses

◦Temporarily assigned, randomly generated value that changes over time

◦A value assigned by a stateful address configuration protocol

◦A value assigned during a Point-to-Point Protocol connection establishment

◦A manually configured value


MAC 48, EUI-48, EUI-64Company IDExtension IDU/L bit (u)

◦Universally (=0)/Locally (=1) AdministeredU/G bit (g)

◦Unicast (=0)/Group (=1) Address

ccccccug cccccccc cccccccc

24 bits 24 bits

xxxxxxxx xxxxxxxx xxxxxxxx

IEEE-administered company ID Manufacturer-selected extension ID


IEEE EUI-64 AddressesExtended Unique IdentifierCompany IDExtension ID


24 bits 40 bits

xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx



Conversion of an IEEE 802 Address to an EUI-64 Address


24 bits 24 bits


ccccccug cccccccc cccccccc xxxxxxxx xxxxxxxx xxxxxxxx11111111 11111110

0xFF 0xFE


EUI-64 Address

IEEE 802 Address


Conversion of an EUI-64 Address to an IPv6 Interface ID

ccccccug cccccccc ccccccccxxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx

EUI-64 Address

ccccccUg cccccccc ccccccccxxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx

IPv6 Interface Identifier

Complement the universally/locally administered (U/L) bit


Conversion of an IEEE 802 Address to an IPv6 Interface ID

cccccc00 cccccccc cccccccc xxxxxxxx xxxxxxxx xxxxxxxx1111111111111110

0xFF 0xFE

EUI-64 Address

cccccc00 cccccccc cccccccc

24 bits 24 bits



IEEE 802 Address

cccccc10 cccccccc cccccccc

64 bits

11111111 11111110 xxxxxxxx xxxxxxxx xxxxxxxx

IPv6 Interface Identifier


IEEE 802 Address Conversion Example

Host A has the MAC address of 00-AA-00-3F-2A-1C1. Convert to EUI-64 format

◦ 00-AA-00-FF-FE-3F-2A-1C

2. Complement the U/L bit◦ The first byte in binary form is 00000000. When the seventh bit is

complemented, it becomes 00000010 (0x02). ◦ Result is 02-AA-00-FF-FE-3F-2A-1C

3. Convert to colon hexadecimal notation◦ 2AA:FF:FE3F:2A1C

Link-local address for node with the MAC address of 00-AA-00-3F-2A-1C is FE80::2AA:FF:FE3F:2A1C.


Temporary Address Interface Identifiers

Random IPv6 interface identifier◦Prevent identification of traffic regardless of

the prefix◦ Initial value based on random number◦Future values based on MD5 hash of history

value and EUI-64-based interface identifierResult is a temporary address

◦Generated from public address prefixes using stateless address autoconfiguration

◦Changes over time


Mapping IPv6 Multicast Addresses to Ethernet AddressesIPv6

Multicast Address8 16 24 32

FF...:

33-33-

Ethernet Multicast Address

For example: an host with MAC address of 00-AA-00-3F-2A-1C (i.e., link-local IPv6 address is FE80::2AA:FF:FE3F:2A1C) adds the followingMulticast MAC addresses to the table of interesting destination MAC addressesOn the Ethernet adaptor:

• The address of 33-33-00-00-00-01, which corresponding to FF02::1• the address of 33-33-FF-3F-2A-1C, which corresponds to the solicited-node

address of FF02::1:FF3F:2A1C. (Remember that the solicited address is the Prefix FF02::1:FF00:0/104 and the last 24 bits of the unicast IPv6 address.


IPv4 Addresses and IPv6 Equivalents

IPv4 Address IPv6 AddressInternet address classes N/AMulticast addresses (224.0.0.0/4) IPv6 multicast addresses (FF00::/8)Broadcast addresses N/AUnspecified address is 0.0.0.0 Unspecified address is ::Loopback address is 127.0.0.1 Loopback address is ::1Public IP addresses Aggregatable global unicast addressesPrivate IP addresses Site-local addresses (FEC0::/48)APIPA addresses [RFC 3927] Link-local addresses (FE80::/64)Dotted decimal notation Colon hexadecimal formatSubnet mask or prefix length Prefix length notation only


Review

IPv6 address spaceIPv6 address syntaxUnicast IPv6 addressesMulticast IPv6 addressesAnycast IPv6 addressesIPv6 interface identifiersIPv4 addresses and IPv6 equivalents

資管 lee lesson 3 ipv4/v6 addressing. 資管 lee lesson objectives ipv6/v4 address space ipv6...

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資 管 lee lesson 3 ipv4/v6 addressing. 資 管 lee lesson objectives ipv6/v4 address space ipv6...

資管 lee lesson 3 ipv4/v6 addressing. 資管 lee lesson objectives ipv6/v4 address space ipv6...