IPv6

Chapter 16

Chapter 1 2

Chapter Objectives

Explain the benefits and uses of IPv6 Explain global unicast addressing, routing and subnetting Explain IPv6 Protocols and Addressing Configure IPv6 Routing and Routing Protocols Explain the IPv6 transition options

Chapter 1 3

Recall DH-1 has the key length of 768 bits. Similarly, DH2 and

DH5 have 1024 bits and 1536 bits respectively. Message integrity is a process in which a receiving VPN

device verifies that the data packet is not changed while transmission.

Authentication is a process in which a receiving VPN device verifies that the received packet is sent by an authorized VPN device.

VPN can be configured by using the hostname, local name or L2TP tunnel password.

Chapter 1 4

Benefits and uses of IPv6 - I

Supports the features of the security protocol such as IPSec to provide secure communication over the Internet.

Provides a way to change addresses that are assigned to the hosts for maintaining address assignment within a site.

Chapter 1 5

Benefits and uses of IPv6 - II

Provides globally unicast addressing removes the need for NAT/PAT

IPv6 address assignment allows easier renumbering, dynamic allocation and recovery of addresses.

IPv6 routers do not recalculate a header checksum for every packet, reducing overhead per packet.

Chapter 1 6

Global Route Aggregation for Efficient Routing The strategies for IPv6 address assignment are as

follows: Public IPv6 addresses are grouped by major

geographical area. Address space is further sub-divided by ISP inside

each area. Address space inside each ISP in an area is further

sub-divided for each customer.

Chapter 1 7

Using DHCP for IPv6 IPv6 hosts use the DHCP protocol, to get the IP

address, default router IP address, prefix length (mask) and the DNS IP address.

Using DHCP, the host sends the IPv6 packet for searching DHCP server.

The DHCPv4 server is used for IPv4 hosts. The DHCPv4 holds information about the client, such as the IP leased IP and the time period validity.

Chapter 1 8

Operational modes of DHCPv6 server The following are the two operational modes of DHCPv6

server: Stateful mode - In this mode the DHCPv6 server is

same as DHCPv4 server. It helps in tracking the status of the client.

Stateless mode - In this mode the server does not track the status information.

Chapter 1 9

Stateless Auto configuration and Router Advertisements - I The stateless auto configuration, allows the host to

calculate the IP address according to the prefix length used on the subnet.

It calculates the address using EUI-64 interface ID based on its MAC address embedded into Network Interface Card (NIC).

The stateless auto configuration uses the NDP (Neighbor Discovery Protocol) to discover the prefix length used on LAN.

Chapter 1 10

Stateless Auto configuration and Router Advertisements II

It uses the following two NDP messages to discover the IPv6 prefix used on LAN: Router Solicitation (RS) - The host sends an RS

multicast message to all the routers to identify the IPv6 prefix used on the subnet.

Router Advertisement (RA) - The reply message of the router is in the form of an RA message.

Chapter 1 11

Stateless Auto configuration and Router Advertisements III

RS/RA ProcessRS/RA PROCESS

Chapter 1 12

IPv6 Addresses

Types of IPv6 addresses: Unicast - Assigns IP addresses to a single interface

that allows one host to send and receive data. Multicast - Represents IP addresses for a dynamic

group of hosts that send packets to all members of that group.

Anycast - They can be used by the server or routers having same functionality for receiving the packets from the client. The packets will be sent to the closest in routing terms. This kind of addressing balances the load between different servers.

Chapter 1 13

IPv6 Transition Options - I

IPv6 resolves the issues of shortage of IP addresses and larger routing table. A large number of devices use IPv4, this the reason why few devices and their software's do not support IPv6.

Chapter 1 14

IPv6 Transition Options - II

The approaches are developed to migrate from IPv4 to IPv6 are as follows: IPv6 Dual Stacks - IPv4 and IPv6 together can be used

by the host or router at the same time. This is known as Dual stacks.

Tunneling - Tunneling is used for migrating from IPv4 to IPv6. This function takes the IPv6 packet sent by host, encapsulate it in IPv4 packet and forwards it over the Internet. After the IPv4 header is removed the IPv6 packet is revealed.

Chapter 1 15

Summary - I IPv6 is an Internet protocol that supports much larger

addresses space than IPv4. Global unicast addresses are public and globally unique

IPv6 addresses that allow the hosts to communicate over Internet.

IPv6 is represented by 32 hexadecimal numbers organized into 8 blocks, each block containing 4 hexadecimal (hex) digits separated by a colon.

Chapter 1 16

Summary - II You can abbreviate the IPv6 address using the following

rules: Neglecting the leading 0's in every block Putting (::) in place of continuous hex 0s

IPv6 addressing supports classless addressing. It uses prefixes to represent a range of consecutive IPv6 addresses.

DHCP servers are used in two operational modes: Stateful Stateless

Chapter 1 17

Summary - III In stateful DHCPv6, IPv6 hosts use Dynamic Host

configuration (DHCP) protocol, to get the IP address, default router IP address, prefix length (mass) and the DNS IP address.

IPv6 use the following routing protocols: RIPng OSPFv3 MP-BGP4 EIGRP for IPv6

Chapter 1 18

Summary - IV Two approaches are that can be used to migrate from

IPv4 to IPv6 are: IPv6 Dual Stacks Tunneling

Some IPv6-to-IPv4 tunnels that can be used for transition are given as follows: Manually Configured Tunnel (MCT) Dynamic 6to4 tunnels Intra-site automatic tunneling addressing protocol

(ISATAP) Teredo tunneling