Understanding IPv6 Addressing and Network Configuration

Desklib provides past papers and solved assignments for students. This report explores the IPv6 network protocol.

Table of Contents
Introduction to IPv6...................................................................................................................2
What is IPv6?.........................................................................................................................2
Benefits with IPv6..................................................................................................................2
Literature Review.......................................................................................................................4
Network fundamentals...........................................................................................................4
OSI Model..........................................................................................................................4
DHCP.................................................................................................................................5
ARP....................................................................................................................................5
IPv6 REVIEW........................................................................................................................6
References..................................................................................................................................8

Introduction to IPv6
What is IPv6?
An IP address is used to identify a device over a network and the latest version of the Internet
Protocol is the IPv6 protocol, this network layer protocol makes data communication possible
over a packet switched network. The previous version of the internet protocol i.e. the IPv4
protocol is the one that is currently being used and it supports around 4.3 billion devices
using a 32bit addressing scheme. The IPv4 was created with a thought that 32-bit addressing
would be enough and it was something reasonable back in 1970s when it was being
developed. The advancements in technology with rapid growth in mobile devices, notebook
computers and other handheld devices created a need for additional spaces of IP addressing
and to overcome that problem, IPv6 was introduced with 128-bit addressing using eight
groups of four hexadecimal digits that mean it can support devices more than 7.9×1028 times
of what IPv4 can. The problem with the switch over between these two networks is that they
are not interoperable, which means devices using IPv4 cannot work on the IPv6 network and
vice versa. Solutions such as the recent developments in Network Address Translation (NAT)
have made it possible to still make use of IPv4. (Deering & Hinden, 2017)
Benefits with IPv6
An increased number of IP addresses are not the only advantage what IPv6 provides.
Better Routing: The routing table size in IPv6 is reduced and the is hierarchical which
makes the process efficient. With the use of IPv6, ISPs can aggregate the prefixes easily to
the assigned IP networks into single prefixes.
Packet processing: In IPv4 the checksum needs to be calculated at a router hop whereas
there is no IP-level checksum in IPv6. This was done as checksum and error control methods
are already implemented over most link-layer technologies. The packet header in IPv6 is
simplified which makes the packet processing better.
Support for new devices: Services like VoIP and Quality of service (QoS) have improved
with IPv6 as peer to peer networks can be easily created and maintained with IPv6. The
Network Address Translation has been eliminated and end to end connectivity is established.
It also supports Mobile IPv6 (MIPv6) which makes it possible for the mobile devices to
change networks regardless of physical location.

Security: To improve upon the security measures, IPSec is embedded into IPv6 for increased
authentication and privacy. IPv4 ICMP packets are often blocked at some places due to their
potential of carrying malware but with ICMPv6 i.e. implementation of Internet control
message protocol for IPv6, the packets may be permitted as IPSec can be applied onto them.
The security framework ensures secure data transmission between hosts independent of any
other applications on either thus providing a better end to end security.
Auto-configuration: IPv6 devices when connected with each other can configure them on
their own, that means they can perform automatic address assignment and numbering which
is a great help to the network administrators.

Literature Review
Network fundamentals
OSI Model
The Open Systems Interconnection (OSI) Reference Model guides developers so that they
can create softwares and applications which can be interoperable, it provides a framework
which lays out the functions of a networking or a telecommunication system. In simple
language, the OSI model provides a framework which helps the applications to be developed
in such a way that they can communicate even over different platforms. The OSI model has
seven layers each serving a different purpose.
Application layer: Application layer is extreme close to user and provides a group of
services which an application should have access to or be able to make use of. Web browsing
applications come under this layer.
Figure 1: The OSI model

Presentation layer: The sixth layer in defined as model which is the presentation layer
which is a part of the operating system itself. The translation of application format to network
format is provided by this layer and vice versa is also possible. The data is presented for the
application under this layer.
Session layer: A session needs to be created for two systems to communicate with each
other. This layer is responsible for the coordination and termination of the communication.
Transport layer: The management of data packets and their delivery is done under this
layer. TCP and UDP provide these services to applications, this also includes checking for
errors in data when it arrives.
Network layer: The network layer is responsible for transmission of data across multiple
networks. The selection of best route for the transmission of data, traffic control, error control
and congestion control, all happen under this layer.
Data link layer: This layer concerns with transmission of data between nodes in a network.
Logical Link Control (LLC) and Media Access Control (MAC) are the sublayers.
Physical layer: The lowest layer of the OSI model is responsible for representing the
physical and electrical demonstration of entire system. This comprises of radio frequency
link, cable type, pin layout, voltage etc.
DHCP
The Dynamic Host Configuration Protocol is generally used to allocate an IP address
dynamically to a node or a device on a network. With the implementation of this protocol
there is no need for network administrators to manually assign addresses to all network
devices. DHCP also assigns the subnet mask, DNS, gateway address and other configuration
parameters. DHCP simplifies the management of IP addresses on a network as assigning the
addresses manually can be really confusing and may lead to errors. This leads to a reduction
in IP address conflicts as there won’t be any duplicity which can happen when addresses are
assigned manually.
ARP
A machine which is recognized in the local network can be assigned an IP address with the
Address Resolution Protocol. ARP cache maintains the relation of each MAC address and the
respective IP address. A host wishing to acquire a physical address used to sends an ARP

request onto the TCP/IP network, a reply is sent by the host that has the IP address in
particular request. It lies between the second and the third layers of the OSI model. One
drawback of ARP is that no authentication is needed at this level which allows the spoofing
of IP and MAC addresses. (Issac, 2014)
IPv6 REVIEW
Structure
The IPv6 addresses are 128 bit long and are expressed in eight sections of 16 bit each. They
are represented by hexadecimal values with sections ranging from 0 to FFFF. A colon marks
the end of one section and omission of leading zeros is allowed. Two or more sections with
consecutive sections of zeros can be collapsed to a double colon.
Sample IPv6 address- 2002:0bb8:34a3:0000:0000:4b2e:0481:6634
Omission of leading zeros of each 16-bit group is done as follows-
3FDE:0:0:1:345:F87F:DD75:20DF » » 3FDE::1:345:F87F:DD75:20DF
There are three types of unicast address schemes for IPv6 address. The last 64 bits are used
for interface ID.
IPv6 Global Unicast Address Prefix
The unicast address in IPv6 is used for single interface identification in a node. The prefix
here is considered a part of particular IPv6 address which indicates the network. The global
unicast address seems to be globally unique in the internet. Whosoever demands an IPv6
addresses need a registered IPv6 address block and this block is assigned as a global rounding
prefix. The addresses are routable on the network and only available for the one who requests
it.
The global unicast addresses begin with hex 2 or three and consist of a subnet ID which are
64 bits long. They also consist of an interface ID that is also 64 bits long and acts like IPv4
host field. Example of the two parts of IPv6 global unicast address:
3 bits 45 bits 16 bits 64 bits
001 Global Routing
Prefix
Subnet ID Interface ID

Link Local Unicast Address
The link-local address is the auto configured IPv6 address. Link local unicast addresses are
only used with a single network link and are invalid if used outside the organization. The 10
bits at the beginning of the prefix are being used to determine the address like an link-local
address. The last 54 bits represent the interface ID.
Example: fe80::123e:456d
The interface ID is the hexadecimal address of the interface derived from the MAC address.
Solicited Node Multicast Address
In simple terms, it is an IPv6 multicast address applicable for a local-link. All the devices
using IPv6 address would compute and join a solicited node multicast group address. For the
IPv6 Neighbour Discovery this address is used. The solicited node multicast group addresses
begin with FF02::1:FF /104:
Figure 2: Solicited Node Multicast
Multicast range- FF/8
Multicast link local scope – FF02/16
The last 24 bits of the IPv6 unicast address make up for the solicited node multicast address.
This also reduces the number of hosts subscribed to each solicited node multicast address.
Intermediate switches can use MLD snooping and send traffic addressed to a solicited node
multicast address to be sent to ports that take to the stations which subscribe to receive the

traffic and this is how the overriding of Ethernet switches from flooding multi-cast frames
can be prevented. (Czyz et. al, 2014)

References
Czyz, J., Allman, M., Zhang, J., Iekel-Johnson, S., Osterweil, E. and Bailey, M., 2014,
August. Measuring ipv6 adoption. In ACM SIGCOMM Computer Communication Review
(Vol. 44, No. 4, pp. 87-98). ACM.
Deering, S. and Hinden, R., 2017. Internet protocol, version 6 (IPv6) specification (No. RFC
8200).
Issac, B., 2014. Secure ARP and secure DHCP protocols to mitigate security attacks. arXiv
preprint arXiv:1410.4398.