What is IPv6 Address and How to Configure IPv6

What is IPv6 Address

IPv6 (Internet Protocol Version 6) is a communication protocol that provides a location system and identification for the computers on the network. Across the Internet, it also routes the traffic. The IETF (Internet Engineering Task Force) grew concerned in the early 1990s about the IPv4 network addresses exhaustion and began to look for this protocol replacement. The activity led to the development of IPv6 (Internet Protocol Version 6) that which is now known as IPv6.

How to Configure IPv6 in Packet Tracer

The capability for future demands to scale networks requires a limitless supply of IP addresses and improved mobility that NAT and private addressing cannot meet alone. IPv6 satisfies the increasingly hierarchical addressing of complex requirements which are not provided by the IPv4.

Difference between IPv4 and IPv6

The binary value of IPv6 is address a 128-bit , which can be displayed as a hexadecimal 32 digits. Sufficient addresses are provided by the IPv6 for future Internet growth needs for many years to come.

The powerful enhancement to IPv4 is the IPv6 network address and the IPv6 several features offer functional improvements.

1. Simpler Header

Several advantages are offered by a simpler header over IPv4:

v Better efficiency of routing for forwarding-rate scalability and performance.
v No potential threat of storms broadcast because of no broadcast.
v There are no requirements for processing checksums.
v More efficient and simpler extension header mechanism.
v Flow labels for processing per flow without opening the inner packet of transport to identify the several traffic flows.

2. Larger Address Space

Several enhancements are included in a larger address space:

v Improved flexibility and global reachability.
v Prefixes aggregation that is announced in routing tables.
v Multi-homing to several ISPs.
v Auto-configuration in the address space that includes addresses of the Data-Link Layer.
v Options of Plug and Play.
v Readdressing end to end of the public to private without translation address
v Simplified Mechanisms for address modification and renumbering.

3. Transition Strategies

Incorporate the existing capabilities of IPv4 with the added features of IPv6 in several ways:

v Implementation of the dual-stack method, with both configured IPv4 and IPv6 on the network device interface.

v Use tunneling as the adoption of IPv6 growth which will become more prominent.

v Between the IPv4 and IPv6 the Cisco IOS software Release 12.3 (2) T, and later include NAT-PT (Network Address Translation-Protocol Translation).

4. Security and Mobility

It helps to ensure compliance with IPsec standards and mobile IP functionality. Mobility enables people to move around the networks with mobile network devices many with wireless connectivity.

v Mobility is built-in in IPv6, which means that any node in IPv6 can use mobility when necessary.
v Mobile devices are not automatically enabled in IPv4 to move without breaks in established network connections.
v On every node of IPv6 the IPsec is enabled and is available for use, making the Internet of IPv6 more secure.

Address Structure of IPv6

The address of Ipv4 is a 32-bit address as a series of four 8-bit fields, separated by dots. The largerIPv6 addresses which are 128-bit need a different representation because of their size.

IPv6 addresses Writing Conventions

The 32 hexadecimal numbers are used in IPv6 conventions, organized into 8 quarters of 4 hexadecimal digits that are separated by a colon, to represent a 128-bit IPv6 address.

For example: 1224:2222: BBBB: 0001:2341:7865:3BCD

To make the things a bit easier, two conventions allow you to shorten what must be typed for an IPv6 address:

v In any given quarter, omit the leading 0s.
v Represent 1 or more consecutive quarters of all hexadecimal 0s with a double colon (::), but in a given address only for one such occurrence.

For example: Consider the following address, the bold digits represent the digits in which the address could be abbreviated. FE00:0000:0000:0005:0000:0000:0000:0012

The above address has two locations in which one or more quarters have four hexadecimal 0s, so using the (:: )abbreviation in one or the other location, two main options exist for abbreviating this address.

The following two options show the valid two abbreviations:

v FE00::5:0:0:0:12
v FE00:0:0:5::12

In the first option, the quarters second and third preceding 0005 were replaced with (::). In the second option, the quarters fifth, sixth, and seventh were replaced with (::). In particular, note that the abbreviation (::), meaning “all 0s in one or more quarters” cannot be used twice, because that would be ambiguous. So, the abbreviation FE00::5::12 would not be valid.

IPv6 Prefixes Writing Conventions

A block or range of consecutive IPv6 addresses is represented in IPv6 prefixes. The “Prefix” means the number that represents the range of addresses, and it is usually seen in IP routing tables, the same as IP subnet numbers in the routing table of IPv4.

As with IPv4, when typing or writing a prefix in IPv6, the bits past the end of the prefix length are all binary 0s. The following address of IPv6 is an example of an address assigned to a host:

2000:2342:4578:4ABC:1234:5648:4ABC:1111/64

The prefix in which the above address resides would be as follows:

2000:2342:4578:4ABC:0000:0000:0000:0000/64

This would be when abbreviated:

2000:2342:4578:4ABC:: /64

If the length of the prefix doesn’t fall on a boundary of the quartet, the prefix value in the last quartet should list all the values. For example, assume the length of the prefix is /56 in the previous example. So, the rest of the fourth quarter should be written by convention, after being set to binary 0s as follows:

2000:2342:4578:4A00::/56

The following list summarizes some key points about how to write the IPv6 prefixes:

v As the IP addresses, the prefix has the same value in the group for the first number of bits, as defined by the prefix length.
v The prefix length number of bits after any bits is binary 0s.
v With the same values the prefix can be abbreviated as IPv6 addresses.
v Write down the value for the entire quartet if the length of the prefix is not on a quartet boundary.

IPv6 Prefix

Global Unicast Address of IPv6

The format of the IPv6 address enables aggregation upward eventually to the ISP. The global unicast address of an IPv6 is globally unique. It can be routed on the Internet without any modification similar to an IPv4 public IP address. The global unicast address of IPv6 consists of a 48-bit global routing prefix and a 16-bit subnet ID, as shown in the below figure:

IPv6 Address

The current global unicast address uses the range of addresses assigned by the IANA that starts with binary value 001 (2000::/3), which is one-eighth of the total address space of IPv6 and is the largest block of assigned addresses.

IPv6 Address Types

There are three types of IPv6 addresses:

v Unicast: Uniquely identifies an interface on an IPv6-enabled device.

vMulticast: sends a single IPv6 packet to multiple destinations.

vAnycast: Any IPv6 unicast address that can be assigned to multiple devices. For example, a packet sent to an anycast address is routed to the nearest device having that address.

Note: IPv6 does not have a broadcast address but Pv4 has. However, there is an address that essentially gives the same result which is the IPv6 all-nodes multicast address.

Reserved, Private, and Loopback Addresses

The portion of IPv6 address space is reserved by the IETF for various uses in both the present and future and the reserved addresses represent 1/256 of the total address space of IPv6. Some other types of IPv6 addresses come from this block.

Like IPv4, a block of IPv6 addresses is set aside for private addresses. These private addresses are never routed outside a particular company network, only these addresses are local to a particular site or link. The hexadecimal notation FE value in the first octet is a private address, with the next digit of hexadecimal being a value from 8 to F.

Further, these addresses are divided into two types based on their scope

Site-Local Addresses

These addresses are for an organization or for an entire site, but the site-local address uses are problematic and depreciated as of 2003 by RFC 3879. The site-local addresses in hexadecimal notation begin with FE and the C to F for the third hexadecimal digit. So, these private addresses start with FEC, FED, FEE, or FEF.

Link-Local Addresses

The scope of link-local addresses is small than site-local addresses; these are referred to only a particular physical network (physical link). The datagrams are not forwarded by the router using link-local addresses not even within the organization, on a particular physical network segment they are only for local communication. They are used for link communications such as neighbor discovery, router discovery, and automatic address configuration.

The link-local addresses are used by many IPv6 routing protocols and these addresses begin with FE and then have a value from 8 to B for the third hexadecimal digit. These addresses are start FEA, FEB, or FE8, FE9.

For a special loopback IPv6 address testing, a provision has been made just as in IPv4. The address 0:0:0:0:0:0:0:1 is the loopback address which is normally expressed using zero compression as::1.

In the below topology diagram, the abbreviated addresses are used. For example, 2001::1 is the abbreviated address from 2001:0000:0000:0000:0000:0000:0000:0001.

How to Configure IPv6 using Packet Tracer

Basic Configuration of Routers R1, R2, and R3

Configuring the Router R1

Router> enable

Router# configure terminal

Enter configuration commands, one per line. End with CNTL / Z.

Router (config) # hostname R1

R1 (config) # interface serial 0/1/0

R1 (config) #exit

R1#

Configuring the Router R2

Router> enable

Router# configure terminal

Enter configuration commands, one per line. End with CNTL / Z.

Router (config) # hostname R2

R2 (config) #end

R2#

Configuring the Router R3

Router> enable

Router# configure terminal

Enter configuration commands, one per line. End with CNTL / Z.

Router (config) # hostname R3

R3 (config) #end

R3#

IPv6 Verification on Routers R1, R2, and R3

Router R1

R1# show ipv6 interface brief

IPv6 interface

R1# show ipv6 route

IPv6 Route

Router R2

R2# show ipv6 interface brief

IPv6 interface

R2# show ipv6 route

IPv6 Route

Router R3

R3# show ipv6 interface brief

IPv6 interface

R3# show ipv6 route

IPv6 Route

R1# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

R1 (config) # ipv6 unicast-routing

Enabling IPv6 on Routers R1, R2, and R3 interfaces

Router R1

R1 (config) # interface fa0/0

R1 (config-if) # ipv6 enable

R1 (config-if) # ipv6 address 2001::1/64

R1 (config-if) # no shutdown

R1 (config-if) #exit

R1 (config) # interface S 0/1/0

R1 (config-if) # ipv6 enable

R1 (config-if) # ipv6 address 2002::1/64

R1 (config-if) # no shutdown

R1 (config-if) #exit

R1 (config) # interface S 0/1/1

R1 (config-if) # ipv6 enable

R1 (config-if) # ipv6 address 2004::1/64

R1 (config-if) # no shutdown

R1 (config-if) #end

R1#

Router R2

R2# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

R2 (config) # interface fa0/0

R2 (config-if) # ipv6 enable

R2 (config-if) # ipv6 address 2003::1/64

R2 (config-if) # no shutdown

R2 (config-if) #exit

R2 (config) # interface S 0/1/0

R2 (config-if) # ipv6 enable

R2 (config-if) # ipv6 address 2002::2/64

R2 (config-if) # no shutdown

R2 (config-if) #exit

R2 (config) # interface S 0/1/1

R2 (config-if) # ipv6 enable

R2 (config-if) # ipv6 address 2005::1/64

R2 (config-if) # no shutdown

R2 (config-if) #end

R2#

Router R3

R3# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

R3 (config) # interface fa0/0

R3 (config-if) # ipv6 enable

R3 (config-if) # ipv6 address 2006::1/64

R3 (config-if) # no shutdown

R3 (config-if) #exit

R3 (config) # interface S 0/1/1

R3 (config-if) # ipv6 enable

R3 (config-if) # ipv6 address 2004::2/64

R3 (config-if) # no shutdown

R3 (config-if) #exit

R3 (config) # interface S 0/1/0

R3 (config-if) # ipv6 enable

R3 (config-if) # ipv6 address 2005::2/64

R3 (config-if) # no shutdown

R3 (config-if) #end

R3#

Routing Tables of Routers R1, R2, and R3

Router R1

R1# show ipv6 route

IPv6 Route

R1# show ipv6 interface brief

IPv6 interface

Router R2

R2# show ipv6 route

IPv6 Route

R2# show ipv6 interface brief

IPv6 interface

Router R3

R3# show ipv6 route

IPv6 Route

R3# show ipv6 interface brief

IPv6 interface

Ping Verification on Routers R1, R2, and R3

Router R1

R1# ping 2002::2

Ping verification

R1# ping 2005::1

Unsuccessful Ping verification

Note: The ping wasn’t successful because the IPv6 address 2005::1 is not listed in the Router R1 routing table. So, to make the ping successful we will have to configure static or dynamic routing.

Router R2

R2# ping 2002::1

Ping verification

R2# ping 2004::1

Unsuccessful Ping verification

Note: The ping wasn’t successful because the IPv6 address 2004::1 is not listed in the Router R2 routing table. So, to make the ping successful we will have to configure static or dynamic routing.

Router R3

R3# ping 2005::1

Ping verification

R3# ping 2002::2

Unsuccessful Ping verification

Note: The ping wasn’t successful because the IPv6 address 2002::2 is not listed in the Router R3 routing table. So, to make the ping successful we will have to configure static or dynamic routing.

Configuring Static Routes on Routers R1, R2, and R3

Router R1

R1# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

R1 (config) # ipv6 route?

IPv6 Route Prefix