Shreehari Dhat

Background of IP addressing.

IPv6 Terminology.

What’s new in IPv6?

IPv6 Packet Format.

IPv6 Addressing architecture.

IPv6 configuration on Windows/Linux.

IP address is logical (implemented in software).

IP address is used to identify a host over the network.

IPv4 is most widely and commonly implemented.

Range of IPv4 address.

IPv4 is 32 bit long address.

About 4,29,49,67,296 addresses are available.

IANA (Internet Assigned Numbers Authority) manages the IP address allocation globally.

IPv4 address classes.

Class A address :- 0.0.0.0 – 127.255.255.255

Class B address :- 128.0.0.0 – 191.255.255.255

Class C address :- 192.0.0.0 – 223.255.255.255

Class D address :- 224.0.0.0 – 239.255.255.255 (Multicast)

Class E address :- 240.0.0.0 – 255.255.255.255 (Experimental)

Class A, B & C are mainly used for allocating IP addresses locally & globally.

Global IP address and Local IP address

Global IP (Know Yip)

Global IP

ISP Backbone N/W

Global IP

Global IP

Organization 1

Organization 2

Organization 3

Internet

LAN

Number of networks and hosts/network in A, B & C

Class A :- 256 Networks, 1,67,77,216 hosts/network.

Class B :- 65,536 Networks, 65,536 hosts/network.

Class C :- 1,67,77,216 Networks, 256 hosts/network.

These numbers are derived from default NetMasks.

Class A :- 255.0.0.0

Class B :- 255.255.0.0

Class C :- 255.255.255.0

Host:- Any computer which is not a router.

Interface:- Connection to link.

Link:- The medium for transmission.

Link-Layer Identifier:- MAC address.

Prefix:- Initial bits in IP address.

Interface Address:- Addresses assigned to NIC.

Multicast:- One to Many.

Neighbors:- computers attached to same link.

Larger address space i.e.

128 bits address.

Address count:- 340,282,366,920,938,463,463,374,607,431,768,211,456 (3.4 × 10^38)

Almost all blocks of IPv4 address have been assigned globally.

The last unassigned top-level address blocks of 16 million IPv4 addresses were allocated in February 2011.

Was there an IPv5 before IPv6?

Ans:- Yes. It was experimental protocol. Basically designed for streaming purpose (QoS).

IPv4 IPv6

Address space:- 4.4 billion addresses only. Address space:- trillions of addresses.

IP Security (IPSec) is optional.Fragmentation at sender & routers.

In-built IPSec support.Fragmentation only at sender level.

Option fields are part of header.Header length + Protocol length.

New Extension header added to IP header.Only Payload length.

Broadcast messages.Address Resolution Protocol.

No broadcast in IPv6.Neighbor discovery protocol.

Address allocation is based on class.No router advertisement.No Stateless address allocation.

Address allocation is based on network prefix. Router advertisement.Stateless address allocation (Link Local).

Version Traffic Class Flow Label

Payload Length Next Header Hop Limit

Source Address

Destination Address

Version :- 4-bit Internet Protocol version number = 6.

Traffic Class :- 8-bit traffic class field.

Flow Label :- 20-bit flow label. Determine the packet sequence.

Payload Length :- 16-bit unsigned integer. Length of the

IPv6 payload, i.e., the rest of the packet following this IPv6 header, in octets.

Next Header :- 8-bit selector. Identifies the type of header immediately following the IPv6 header

Hop Limit :- 8-bit unsigned integer. Decremented by 1 by each node that forwards the pac-

ket. The packet is discarded if Hop Limit is decremented to zero.

Source & Destination Address :- 128-bit address.

Extension Headers:-Order of Processing headers

IPv6 headerHop-by-Hop Options header (0)

Destination Options header-(First) Routing header (43)

Fragment header (44)Authentication header (51)

Encapsulating Security Payload header (50)Destination Options header-(Last) (60)

upper-layer header(6-TCP, 17-UDP, 58-ICMP)

Each Extension header has two fields mandatory:-

Some of the headers are not examined or processed by router.

So improved performance for transmission of data.

Only Hop-by-Hop EH is compulsory.

Header specific data

Next Header Hdr Ext Len

IPv6 is implemented with 128 bit addressing mechanism.

Three basic types of addresses

1. Unicast – Single receiver interface address.

2. Multicast – A group of receivers.

3. Anycast – One of nearest interface addresses.

IPv6 addresses are assigned to interface, not hosts/nodes.

Single interface can have multiple IPv6 addresses.

No broadcast addresses in IPv6.

Representation of IPv6 address.

16 Bits

FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

1111 1110 1101 1100:10111010 1001 1000:0111 0110 0101 0100:0011 0010 0001 0000: 1111 1110 1101 1100:10111010 1001 1000:0111 0110 0101 0100:0011 0010 0001 0000

Examples

FEDC:BA98:7654:0000:0000:0000:0000:3210

Or FEDC:BA98:7654:0:0:0:0:3210

Successive 0s can be replaced with :: but only once.

FEDC:BA98:7654:0000:0000:0000:0000:3210

FEDC:BA98:7654::3210

But this is wrong:-

FEDC:0000:0000:0000:FEDC:0000:0000:3210

FEDC::FEDC::3210

Unspecified address

0:0:0:0:0:0:0:0 or ::

Loopback address

0:0:0:0:0:0:0:1 or ::1

IPv4 mapped IPv6 address

::ffff:c000:0280 ::ffff:192.0.2.128

URL with IPv6 address

http://[2001:1:4F3A::206:AE14]:8080/index.html

Global Unicast Address:-

3 Bits 13 Bits 8 Bits 24 Bits 16 Bits

001 - Identifies the address as an IPv6 Unicast global address.

TLA ID - Identifies the highest level in the routing hierarchy. TLA IDs are administered by IANA.

RES – Reserved for future use.

NLA ID - Identifies a specific customer site.

SLA ID - Enables as many as 65,536 (216) subnets within an individual organization’s site. The SLA ID is assigned within the site; an ISP cannot change this part of the address.

Interface ID - Identifies the interface of a node on a specific subnet.

001 TLA ID SLA IDRES NLA ID Interface ID (64 bits)

Link Local address:- Automatically generated by OS using MAC address.

FE80::250:56FF:Fe8F:775F/10. A & B can communicate directly, but not with C, D & vice versa.

A B C D

LAN Switch

Generation of Link-local IPv6 address.

MAC address - 00:50:56:8F:52:AA

Insert FFEE in the middle of MAC address and make a group of 2 bytes.

0050:56FF:FE8F:52AA 0000 0000 0101 0000 : 0101 0110 1111 1111 : 1111 1110 1000 1111 : 0101 0010 1010 1010

Flip the 2nd bit of highest byte and append FE80 like

FE80::250:56FF:FE8F:52AA

Unicast Site local address.

10 Bits 32 Bits 16 Bits 64 Bits

Starts with FEC0: prefix

Similar to IPv4 Private address.

Provides 65,536 subnets.

1111 1110 11 All 0’s Subnet ID Interface ID

Multicast IPv6 address

8 Bits 4 Bits 4 Bits 112 Bits

Starts with FF prefix.

The 4 bit flag indicates whether it’s a well-known multicast or dynamic multicast address.

The 4 bit SC indicates whether it’s a link local, site local or global multicast.

Group ID is unique within a scope.

1111 1111 Flag Group IDSC

Configure IPv6 in Linux.

Refer link :- http://www.tldp.org/HOWTO/Linux+IPv6-HOWTO/chapter-configuration-address.html

Configure IPv6 in Solaris.

Refer link :- http://docs.oracle.com/cd/E19253-01/816-4554/ipv6-config-tasks-64/index.html

Configure IPv6 in Windows:- It is same as configuring IPv4 from Control Panel.