report on ip addressing
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(MAHARANA PRATAP UNIVERSITY OF AGRICULTURE & TECHNOLOGY) Udaipur (Raj.)
A PROJECT REPORT ON INTERNET
PROTOCOL (IP) ADDRESSING
Submitted by:
Ali Asgar Ashiq Hussain
Abhimanyu Kapoor
BE II Year IT
CTAE, Udaipur
Submitted to:
Mr. Dharam Singh
Training In-charge
Department of Information Technology
CTAE, Udaipur
ACKNOWLEDGEMENT
The beatitude, bliss and euphoria that accompany the successful competition
of any task would not be completed without the expression of appreciation of
simple virtues to the people who made it possible. So with reverence, veneration
and honor I acknowledge all those whose guidance and encouragement has made
me successful in winding up this.
First I would like to express my gratitude to Mr. Naveen Malkani for
his valuable guidance encouragement during the completion of training. He was a
major support to me throughout my training, being available with his ideas,
inspiration and encouragement. It is through their masterful guidance that I have
been able to complete my practical training.
The successful completion of training is generally not an individual effort. It
is an outcome of the cumulative effort of a number of persons, each having their
own importance to the objective. This section is a vote of thanks and gratitude all
those persons who have directly or indirectly contributed in their own special way
towards the completion of this dissertation.
Ali Asgar Ashiq Hussain
INTRODUCTION
The internet as we see today is a network of networks, a virtual world
where any computer on internet appears to be connected to every other
computer present on Internet.
The glue that holds the internet together is the IP (Internet Protocol). It
was designed from beginning with internetworking in mind. Its job is to
provide is to provide best-efforts way to transport datagrams from
source to destination, without regard to whether these machines are on
the same network or whether there are other networks in between them.
The Internet Protocol also has the task of routing data packets between
networks, and IP Addresses specify the locations of the source and
destination nodes in the topology of the routing system.
The above window is used to manually configure the IP Address of any
PC running Microsoft Windows. In this the first half is used to configure
IP Address and the second half is used to configure the DNS server.
When the Obtain an IP address automatically is checked the computer
itself finds a DHCP server in the network and obtains an IP address
dynamically from it.
When the Use the following IP address is checked we can manually
assign an IP address to the current Network Interface. It has 3 entries:
IP address: The IP address to be assigned to current Network
Interface.
Subnet Mask: This entry is done automatically by the computer
seeing the IP address assigned. It can also be assigned manually.
Default Gateway: This entry is the IP address of the Gateway
through which the computer can connect to other networks.
IP ADDRESS
An Internet Protocol (IP) address is a numerical identification and
logical address that is assigned to devices participating in a computer
network utilizing the Internet Protocol for communication between its
nodes. Although IP addresses are stored as binary numbers, they are
usually displayed in human-readable notations, such as 208.77.188.166
(for IPv4), and 2001:db8:0:1234:0:567:1:1 (for IPv6).
The designers of TCP/IP defined an IP address as a 32-bit number and
this system, now named Internet Protocol Version 4 (IPv4), is still in use
today. However, due to the enormous growth of the Internet and the
resulting depletion of the address space, a new addressing system (IPv6),
using 128 bits for the address, was developed in 1995 and last
standardized in 1998.
Every host and router on the internet has an IP address, which encodes
its network number and host number. The combination is unique: in
principle, no two machines on the internet have the same IP address. An
IP address does not actually refer to a host, it really refers to network
interface, so if a host is on two network, it must have two IP addresses.
IP versions
The Internet Protocol (IP) has two versions currently in use, the IPv4
and the IPv6. Because of its prevalence, the generic term IP address
typically still refers to the addresses defined by IPv4.
IP version 4 addresses
IPv4 uses 32-bit (4-byte) addresses, which limits the address space to
4,294,967,296 (232
) possible unique addresses. IPv4 reserves some
addresses for special purposes such as private networks (~18 million
addresses) or multicast addresses (~270 million addresses). This reduces
the number of addresses that can be allocated to end users and, as the
number of addresses available is consumed, IPv4 address exhaustion is
inevitable. This foreseeable shortage was the primary motivation for
developing IPv6, which is in various deployment stages around the
world and is the only strategy for IPv4 replacement and continued
Internet expansion.
IPv4 addresses are usually represented in dot-decimal notation (four
numbers, each ranging from 0 to 255, separated by dots, e.g.
208.77.188.166). Each part represents 8 bits of the address, and is
therefore called an octet.
IPv4 Header:
IPv4 networks
In the early stages of development of the Internet protocol network
administrators interpreted an IP address as a structure of network
number and host number. The highest order octet (most significant eight
bits) was designated the network number and the rest of the bits were
called the host identifier and were used for host numbering within a
network. This method soon proved inadequate as additional networks
developed that were independent from the existing networks already
designated by a network number. The Internet addressing specification
was revised with the introduction of Classful Network Architecture.
IP Address Classes Classful network design allowed for a larger number of individual
network assignments. The first four bits of the most significant octet of
an IP address was defined as the class of the address. Three classes, A,
B, and C were defined for universal unicast addressing and Class D was
defined for multicast and Class E was reserved for future use.
Depending on the class derived, the network identification was based on
octet boundary segments of the entire address. Each class used
successively additional octets in the network identifier, thus reducing the
possible number of hosts in the higher order classes (B and C). The
following table gives an overview of this system.
Table
Class A: Class A addresses are specified to networks with large number
of total hosts. Class A allows for 126 networks by using the first octet
for the network ID. The first bit in this octet, is always set and fixed to
zero. And next seven bits in the octet is all set to one, which then
complete network ID. The 24 bits in the remaining octets represent the
hosts ID, allowing 126 networks and approximately 17 million hosts per
network. Class A network number values begin at 1 and end at 127.
Class B: Class B addresses are specified to medium to large sized of
networks. Class B allows for 16,384 networks by using the first two
octets for the network ID. The two bits in the first octet are always set
and fixed to 1 0. The remaining 6 bits, together with the next octet,
complete network ID. The 16 bits in the third and fourth octet represent
host ID, allowing for approximately 65,000 hosts per network. Class B
network number values begin at 128 and end at 191.
Class C: Class C addresses are used in small local area networks
(LANs). Class C allows for approximately 2 million networks by using
the first three octets for the network ID. In class C address three bits are
always set and fixed to 1 1 0. And in the first three octets 21 bits
complete the total network ID. The 8 bits of the last octet represent the
host ID allowing for 254 hosts per one network. Class C network
number values begin at 192 and end at 223.
Class D and E: Classes D and E are not allocated to hosts. Class D
addresses are used for multicasting, and class E addresses are not
available for general use: they are reserved for future purposes.
Subnet Mask The subnet mask is used by the TCP/IP protocol to determine whether a
host is on the local subnet or on a remote network.
In TCP/IP, the parts of the IP address that are used as the network and
host addresses are not fixed, so the network and host addresses above
cannot be determined unless you have more information. This
information is supplied in another 32-bit number called a subnet mask.
Applying a subnet mask to an IP address allows you to identify the
network and node parts of the address. The network bits are represented
by the 1s in the mask, and the node bits are represented by the 0s.
Performing a bitwise logical AND operation between the IP address and
the subnet mask results in the Network Address or Number. The router
uses the Boolean AND operation with an incoming IP address to ‘lose’
the host portion of the IP addresses i.e. the bits that are '0', and match the
network portion with its routing table. From this, the router can
determine out of which interface to send the datagram. This means that
the 'Don't care bits' are represented by binary 0's whilst the 'Do care bits'
are represented by binary 1's.
For example, using our test IP address and the default Class B subnet
mask, we get:
10001100.10110011.11110000.11001000 140.179.240.200 Class B IP
Address
11111111.11111111.00000000.00000000 255.255.000.000 Default
Class B Subnet Mask
--------------------------------------------------------
10001100.10110011.00000000.00000000 140.179.000.000 Network
Address
Default subnet masks:
Class A - 255.0.0.0 - 11111111.00000000.00000000.00000000
Class B - 255.255.0.0 - 11111111.11111111.00000000.00000000
Class C - 255.255.255.0 -
11111111.11111111.11111111.00000000
The same mask is applied throughout the physical networks that share
the same subnet part of the IP address. All devices connected to the
networks that compose the subnet must have the same mask.
Subnets All hosts on a network must have the same network number. This
property of IP addressing can cause problems as networks grow. The
problem is the rule that a single class A, B or C address refers to one
network not a collection of LANs. Thus when many computers are
connected the broadcast requests and other network traffic lead to
network blockages. To avoid this situation we have two options:
Acquire a new network address for each network
Divide the current network into more sub-networks.
Getting a new network address for each sub-network may not be
economical and the IP addresses of the current network get wasted.
The solution is to allow a network to be split into several parts for
internal use but still act like a single network to the outside world. The
parts of the networks are called Subnets.
Sub-netting breaks a network into smaller realms that may use existing
address space more efficiently, and, when physically separated, may
prevent excessive rates of Ethernet packet collision in a larger network.
The technique of sub-netting can operate in both IPv4 and IPv6
networks. The IP address is divided into two parts: the network address
and the host identifier.
Variable Length Subnet Mask
Variable Length Subnet Mask (VLSM) is used by the ISPs to reduce
Wastage of IP Addresses.
A Variable Length Subnet Mask (VLSM) is a means of allocating IP
addressing resources to subnets according to their individual need rather
than some general network-wide rule.
For Example: We require 6 different sub-networks having different
number of computers. Since we require maximum 30 computers in any
network we can take 3 MSBs of Host ID into network ID.
The following comparison shows the wastage of IP Addresses in
Subnetting and VLSM technique:
Requirement
(A)
Subnetting
Before
VLSM (B)
Wastage
(B-A)
Sub-netting
After
VLSM(C)
Wastage
(C-A)
30 30 00 30 00
20 30 10 20 10
10 30 20 14 04
08 30 22 14 06
04 30 26 06 02
02 30 28 02 00
74 180 106 86 22
The VLSM was introduced as a technique to delay the IPv4 Exhaustion.
It was based not on the number of sub-networks required but on the
number of hosts in any particular network. This technique considerably
reduced IP wastage but lead to another problem of routing. VLSM was
not supported by many older routers and switches and hence
implementing them required some hardware up-gradation which was not
economical.
The comparison between IP Network IDs for Subnetting and VLSM
Simple Subnetting Variable Length Subnet Mask
Network ID Subnet Mask Network ID Subnet Mask
192.168.0.32 255.255.255.224 192.168.0.32 255.255.255.224
192.168.0.64 255.255.255.224 192.168.0.64 255.255.255.224
192.168.0.96 255.255.255.224 192.168.0.96 255.255.255.240
192.168.0.128 255.255.255.224 192.168.0.112 255.255.255.240
192.168.0.160 255.255.255.224 192.168.0.128 255.255.255.248
192.168.0.192 255.255.255.224 192.168.0.136 255.255.255.252
Private IP Addresses
In the Internet addressing architecture, a Private Network is a network
that uses private IP address space, following the standards set by RFC
1918 and RFC 4193. These addresses are commonly used for home,
office, and enterprise local area networks (LANs), when globally
routable addresses are not mandatory, or are not available for the
intended network applications. Private IP address spaces were originally
defined in an effort to delay IPv4 address exhaustion, but they are also a
feature of the next generation Internet Protocol, IPv6.
These addresses are characterized as private because they are not
globally delegated, meaning they are not allocated to any specific
organization, and IP packets addressed by them cannot be transmitted
onto the public Internet. Anyone may use these addresses without
approval from a regional Internet registry (RIR). If such a private
network needs to connect to the Internet, it must use either a network
address translator (NAT) gateway, or a proxy server.
The most common use of these addresses is in residential networks,
since most Internet service providers (ISPs) only allocate a single
routable IP address to each residential customer, but many homes have
more than one networked device, for example, several computers and a
video game console. In this situation, a NAT gateway is usually used to
enable Internet connectivity to multiple hosts. Private addresses are also
commonly used in corporate networks, which for security reasons, are
not connected directly to the Internet. In both cases, private addresses
are often seen as enhancing security for the internal network, since it is
difficult for an Internet host to connect directly to an internal system.
The Internet Engineering Task Force (IETF) has directed the Internet
Assigned Numbers Authority (IANA) to reserve the following IPv4
address ranges for private networks, as published in RFC 1918:
RFC19
18
name
IP address
range
number
of
address
es
classful descrip
tion
largest CIDR bl
ock (subnet
mask)
hos
t id
siz
e
24-bit
block
10.0.0.0 –
10.255.255.2
55
16,777,2
16 single class A
10.0.0.0/8
(255.0.0.0)
24
bits
20-bit
block
172.16.0.0 –
172.31.255.2
55
1,048,57
6
16 contiguous
class B's
172.16.0.0/12
(255.240.0.0)
20
bits
16-bit
block
192.168.0.0 –
192.168.255.
255
65,536 256 contiguous
class C's
192.168.0.0/16
(255.255.0.0)
16
bits
Public IP Addresses
The IP Addresses provided by the Internet Service Providers (ISPs) are
called Public IP Addresses. These addresses are recognizable on the
internet and any machine connecting to internet must have a Public IP
Address. These addresses are provided by the Regional Internet
Registries to the ISPs.
The machines which are assigned Private IP Address must go on the
Internet via NAT server having Public IP Address.
The IP Address Ranges not included in the Private IP Address Ranges
are Public IP Ranges.
Broadcast Address
Broadcast address refers to the ability to address a message that is
broadcast to all stations or hosts on a network. Ethernet networks are
shared-media networks in which computers transmit signals on a cable
that all other computers attached to the cable can receive. Thus, all the
computers are part of the same "broadcast domain."
A broadcast address is an IP address that allows you to target all systems
on a specific subnet instead of single hosts. The broadcast address of any
IP address can be calculated by taking the bit compliment of the subnet
mask, sometimes referred to as the reverse mask, and then applying it
with a bitwise OR calculation to the IP address in question.
Normally, one computer transmits frames to only one other computer on
the network by placing the MAC address of the destination computer in
the frame. This frame is then transmitted on the shared media. Even
though other computers see this frame on the network, only the target
receives it. A broadcast message is addressed to all stations on the
network. The destination address in a broadcast message consists of all
1s (0xFFFFFFFF). All stations automatically receive frames with this
address. Normally, broadcast messages are sent for network
management and diagnostic purposes.
On IP networks, the IP address 255.255.255.255 (in binary, all 1s) is the
general broadcast address. You can't use this address to broadcast a
message to every user on the Internet because routers block it, so all you
end up doing is broadcasting it to all hosts on your own network. The
broadcast address for a specific network includes all 1s in the host
portion of the IP address. For example, on the class C network
192.168.1.0, the last byte indicates the host address (a 0 in this position
doesn't refer to any host, but provides a way to refer to the entire
network). The value 255 in this position fills it with all 1s, which
indicates the network broadcast address, so packets sent to
192.168.1.255 are sent to all hosts on the network.
Drawbacks of IPv4
On today’s Internet, IPv4 has the following disadvantages:
Limited address space. The most visible and urgent problem with
using IPv4 on the modern Internet is the rapid depletion of public
addresses. Due to the initial address class allocation practices of
the early Internet, public IPv4 addresses are becoming scarce.
Flat routing infrastructure, i.e. the IP address ranges are not
allocated according to any meaningful hierarchy. In the early
Internet, address prefixes were not allocated to create a
summarizable, hierarchical routing infrastructure. Instead,
individual address prefixes were assigned and each address prefix
became a new route in the routing tables of the Internet backbone
routers. Today’s Internet is a mixture of flat and hierarchical
routing, but there are still more than 85,000 routes in the routing
tables of Internet backbone routers. Thus to reach a router from
one country to another the packet might need to go to a backbone
router in a third country thereby increasing cost and delay.
Security for IPv4 is specified by the use of Internet Protocol
security (IPSec). However, IPSec is optional for IPv4
implementations. Because an application cannot rely on IPSec
being present to secure traffic, an application might resort to other
security standards or a proprietary security scheme. The need for
built-in security is even more important today, when we face an
increasingly hostile environment on the Internet.
Another drawback was the 32 bit header which had much of the
values which were generally never used and which only increased
the bandwidth usage.
A final challenge has been the real-time delivery of multimedia
content and the necessary bandwidth allocation that goes along
with it. A bandwidth allocation method called Quality of Service
(QoS) has been used with IPv4. While QoS does work, there are a
number of different interpretations of the IPv4 QoS standards. This
means that not all QoS-compliant devices are compatible with one
another.
Internet Protocol Version 6
Internet Protocol version 6 (IPv6) is the next-generation Internet
Protocol version designated as the successor to IPv4, the first
implementation used in the Internet that is still in dominant use
currently. It is an Internet Layer protocol for packet-
switched internetworks. The main driving force for the redesign of
Internet Protocol is the foreseeable IPv4 address exhaustion.
The rapid exhaustion of IPv4 address space, despite conservation
techniques, prompted the Internet Engineering Task Force (IETF) to
explore new technologies to expand the Internet's addressing capability.
The permanent solution was deemed to be a redesign of the Internet
Protocol itself. This next generation of the Internet Protocol, aimed to
replace IPv4 on the Internet, was eventually named Internet Protocol
Version 6 (IPv6) in 1995.IPv6 has a vastly larger address space than
IPv4. This results from the use of a 128-bit address, whereas IPv4 uses
only 32 bits. The new address space thus supports 2128
(about 3.4×1038
)
addresses.
This expansion provides flexibility in allocating addresses and routing
traffic and eliminates the primary need for network address
translation (NAT), which gained widespread deployment as an effort to
alleviate IPv4 address exhaustion.
The new design is not based on the goal to provide a sufficient quantity
of addresses alone, but rather to allow efficient aggregation of subnet
routing prefixes to occur at routing nodes. As a result, routing table sizes
are smaller, and the smallest possible individual allocation is a subnet
for 264
hosts, which is the size of the square of the size of the entire IPv4
Internet. IPv6 has facilities that automatically change the routing prefix
of entire networks should the global connectivity or the routing policy
change without requiring internal redesign or renumbering.
Benefits of IPv6
Hierarchical routing infrastructure The Internet is hierarchical in nature, and the IPv6 protocol is designed
with this in mind. Think about it. The computer you're using right now
doesn't have a direct connection to an Internet backbone. Instead, you're
probably behind a NAT firewall, which is connected to an ISP. That ISP
may be connected to another ISP or to a backbone router. Either way, a
packet must make quite a few hops to go from an Internet backbone
router to you.
The IPv6 protocol is designed so that Internet backbone routers will
have much smaller routing tables than they have now. Instead of
knowing every possible route, the routing tables will include routes to
only those routers connected directly to them. The IPv6 protocol will
contain the rest of the information necessary for a packet to reach its
destination.
IPv6 addresses that are reachable on the IPv6 portion of the Internet,
known as global addresses, have enough address space for the hierarchy
of Internet service providers (ISPs) that typically exist between an
organization or home and the backbone of the Internet. Global addresses
are designed to be summarizable and hierarchical, resulting in relatively
few routing entries in the routing tables of Internet backbone routers.
Network security Network security is integrated into the design of the IPv6
architecture. Internet Protocol Security (IPSec) was originally developed
for IPv6, but found widespread optional deployment first in IPv4 (into
which it was back-engineered). The IPv6 specifications
mandate IPSec implementation as a fundamental interoperability
requirement.
The IPv6 protocol has a newly designed IP header. It's designed to make
the protocol more efficient by keeping overhead to a minimum. An IP
packet header is made up of required components and optional
components; in IPv6, the required components are moved to the front of
the header. Optional components are moved to an extension header. This
means that if optional components aren't used, the extension headers
aren't necessary, reducing the packet size.
The downside to the new header is that it isn't compatible with IPv4. If a
router is to handle both IPv4 and IPv6, it must be configured to
recognize both protocols. You can't just set up a router to recognize IPv6
and expect it to be backward-compatible with IPv4.
New configuration options
One of the coolest things about IPv6 is the way it's configured. While
you can still manually configure IPv6, or lease an address from a DHCP
server, there is a new automatic configuration option available. If an un-
configured PC tries to connect to a network that doesn't offer a DHCP
server, the PC can look at either the network's router or the other PCs on
the network and determine an address that would be appropriate for it to
use. This technique is referred to as link local addressing.
Standardized QoS support
IPv6 also includes standardized support for QoS. The QoS
implementation is set up so that routers can identify packets belonging to
an individual QoS flow. This allows those routers to allocate the
necessary amount of bandwidth to those packets. Furthermore, QoS
instructions are included in the IPv6 packet header. This means that the
packet body can be encrypted, but QoS will still function because the
header portion containing the QoS instructions is not encrypted. This
will make it possible to send streaming audio and video over the Internet
with IPSec encryption, but in a manner that guarantees adequate
bandwidth for real-time playback.
Comparison of IPv4 and IPv6 Description IPv4 IPv6
Address 32 bits long (4 bytes).
Address is composed
of a network and a
host portion, which
depend on address
class. Various address
classes are defined: A,
B, C, D, or E
depending on initial
few bits. The total
number of IPv4
addresses is
4,294,967,296.
The text form of the
IPv4 address is
nnn.nnn.nnn.nnn,
where 0<=nnn<=255,
and each n is a
decimal digit. Leading
zeros can be omitted.
Maximum number of
print characters is 15,
not counting a mask.
128 bits long (16 bytes). Basic
architecture is 64 bits for the
network number and 64 bits for the
host number. Often, the host
portion of an IPv6 address (or part
of it) will be derived from a MAC
address or other interface
identifier.
Depending on the subnet prefix,
IPv6 has a more complicated
architecture than IPv4.
The number of IPv6 addresses is
1028
(79 228 162 514 264 337 593
543 950 336) times larger than the
number of IPv4 addresses. The text
form of the IPv6 address is
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:x
xxx:xxxx, where each x is a
hexadecimal digit, representing 4
bits. Leading zeros can be omitted.
The double colon (::) can be used
once in the text form of an address,
to designate any number of 0 bits.
For example,::ffff:10.120.78.40 is
an IPv4-mapped IPv6 address.
Address
allocation
Originally, addresses
were allocated by
Allocation is in the earliest stages.
The Internet Engineering Task
Description IPv4 IPv6
network class. As
address space is
depleted, smaller
allocations using
Classless Inter-
Domain Routing
(CIDR) are made.
Allocation has not
been balanced among
institutions and
nations.
Force (IETF) and Internet
Architecture Board (IAB) have
recommended that essentially
every organization, home, or entity
be allocated a/48 subnet prefix
length. This would leave 16 bits for
the organization to do subnetting.
The address space is large enough
to give every person in the world
their own /48 subnet prefix length.
Address
mask
Used to designate
network from host
portion.
Not used.
Address
prefix
Sometimes used to
designate network
from host portion.
Sometimes written
as /nn suffix on
presentation form of
address.
Used to designate the subnet prefix
of an address. Written as /nnn (up
to 3 decimal digits, 0 <= nnn <=
128) suffix after the print form. An
example is fe80::982:2a5c/10,
where the first 10 bits comprise the
subnet prefix.
Address
Resolution
Protocol
(ARP)
Address Resolution
Protocol is used by
IPv4 to find a physical
address, such as the
MAC or link address,
associated with an
IPv4 address.
IPv6 embeds these functions
within IP itself as part of the
algorithms for stateless auto-
configuration and neighbor
discovery using Internet Control
Message Protocol version 6
(ICMPv6). Hence, there is no such
thing as ARP6.
Description IPv4 IPv6
Address
scope
For unicast addresses,
the concept does not
apply. There are
designated private
address ranges and
loopback. Outside of
that, addresses are
assumed to be global.
In IPv6, address scope is part of
the architecture. Unicast addresses
have two defined scopes, including
link-local and global; and multicast
addresses have 14 scopes. Default
address selection for both source
and destination takes scope into
account.
Address
types
Unicast, multicast,
and broadcast.
Unicast, multicast, and anycast.
Configuratio
n You must configure a
newly installed
system before it can
communicate with
other systems; that is,
IP addresses and
routes must be
assigned.
Configuration is optional,
depending on functions required.
IPv6 can be used with any Ethernet
adapter and can be run over the
loopback interface. IPv6 interfaces
are self-configuring using IPv6
stateless auto-configuration. You
can also manually configure the
IPv6 interface. So, the system will
be able to communicate with other
IPv6 systems that are local and
remote, depending on the type of
network and whether an IPv6
router exists.
Fragments When a packet is too
big for the next link
over which it is to
travel, it can be
fragmented by the
sender (host or
For IPv6, fragmentation can only
occur at the source node, and
reassembly is only done at the
destination node. The
fragmentation extension header is
Description IPv4 IPv6
router). used.
IP header Variable length of 20-
60 bytes, depending
on IP options present.
Fixed length of 40 bytes. There are
no IP header options. Generally,
the IPv6 header is simpler than the
IPv4 header.
IP header
options
Various options that
might accompany an
IP header (before any
transport header).
The IPv6 header has no options.
Instead, IPv6 adds additional
(optional) extension headers. The
extension headers are AH and ESP
(unchanged from IPv4), hop-by-
hop, routing, fragment, and
destination. Currently, IPv6
supports some extension headers.
IP header
Type of
Service
(TOS) byte
Used by QoS and
differentiated services
to designate a traffic
class.
Designates the IPv6 traffic class,
similarly to IPv4. Uses different
codes. Currently, IPv6 does not
support TOS.
Loopback
address
An interface with an
address
of 127.*.*.*(typically
127.0.0.1) that can
only be used by a
node to send packets
to itself. The physical
interface (line
description) is named
LOOPBACK.
The concept is the same as in IPv4.
The single loopback address
is0000:0000:0000:0000:0000:0000
:0000:0001or ::1 (shortened
version). The virtual physical
interface is named LOOPBACK.
Maximum
Transmissio
n Unit
(MTU)
Maximum
transmission unit of a
link is the maximum
number of bytes that a
IPv6 has an architected lower
bound on MTU of 1280 bytes. That
is, IPv6 will not fragment packets
below this limit. To send IPv6 over
Description IPv4 IPv6
particular link type,
such as Ethernet or
modem, supports. For
IPv4, 576 is the
typical minimum.
a link with less than 1280 MTU,
the link-layer must transparently
fragment and defragment the IPv6
packets.
Network
Address
Translation
(NAT)
Basic firewall
functions integrated
into TCP/IP
configured using
iSeries Navigator.
Currently, NAT does not support
IPv6. More generally, IPv6 does
not require NAT. The expanded
address space of IPv6 eliminates
the address shortage problem and
enables easier renumbering.
Node info
query
Does not exist. A simple and convenient network
tool that should work like ping,
except with content: an IPv6 node
may query another IPv6 node for
the target's DNS name, IPv6
unicast address, or IPv4 address.
Currently, not supported.
PING Basic TCP/IP tool to
test reach ability.
Same for IPv6 and IPv6 is
supported.
Private and
public
addresses
All IPv4 addresses are
public, except for
three address ranges
that have been
designated as private
by IETF :10.*.*.*
(10/8),172.16.0.0 thro
ugh172.31.255.255
(172.16/12) ,
and192.168.*.*
(192.168/16). Private
address domains are
commonly used
IPv6 has an analogous concept, but
with important differences.
Addresses are public or temporary,
previously termed anonymous.
Unlike IPv4 private addresses,
temporary addresses can be
globally routed. The motivation is
also different; IPv6 temporary
addresses are meant to shield the
identity of a client when it initiates
communication (a privacy
concern). Temporary addresses
Description IPv4 IPv6
within organizations.
Private addresses
cannot be routed
across the Internet.
have a limited lifetime, and do not
contain an interface identifier that
is a link (MAC) address. They are
generally indistinguishable from
public addresses.
IPv6 has the notion of limited
address scope using its architected
scope designations.
Quality of
service
(QoS)
Quality of service
allows you to request
packet priority and
bandwidth for TCP/IP
applications.
Currently, the i5/OS
implementation of QoS does not
support IPv6.
Renumberin
g
Done by manual
reconfiguration, with
the possible exception
of DHCP. Generally,
for a site or
organization, a
difficult and
troublesome process
to avoid if possible.
Is an important architectural
element of IPv6, and is largely
automatic, especially within
the/48 prefix.
Route Logically, a mapping
of a set of IP
addresses (might
contain only one) to a
physical interface and
a single next-hop IP
address. IP packets
whose destination
address is defined as
part of the set are
Conceptually, similar to IPv4. One
important difference: IPv6 routes
are associated (bound) to a
physical interface (a link, such as
ETH03) rather than an interface.
One reason that a route is
associated with a physical interface
is because source address selection
functions differently for IPv6 than
Description IPv4 IPv6
forwarded to the next
hop using the line.
IPv4 routes are
associated with an
IPv4 interface, hence,
an IPv4 address.
The default route is
*DFTROUTE.
for IPv4.
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