BIS 411 Lecture 5
Transcript of BIS 411 Lecture 5
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BIS 411; Enterprise Network Management
LECTURE FIVE
Topic
IP Addressing and Network Address Translation
Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
Introduction Just as index numbers uniquely identify students of an
institution, IP addresses do same for nodes on IP
networks.
Not all IP addresses assigned to nodes on IP networks
are routable over the Internet.
For every node to get connected to the Internet, they
must be assigned a public IP address which are quite
expensive to acquire from ISPs. NAT is used to reduce the number of Public IP
addresses needed to get connected to the Internet.
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IP Addressing - 1
One of the most basic components of a TCP/IP
network is IP addressing.
An IP address is a numeric identifier assigned
to computers and other communication
devices on an IP network.
Every device on a TCP/IP network must have a
unique IP address.
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
IP Addressing - 2
Unlike MAC addresses which are hard-coded on
the NIC , IP addresses are software or logical
addresses.
IPv4 is a 32-bit number.
IPv6 or IPng is a 128-bit number.
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IP Addressing Terminologies
Bit This is a binary zero or one (0 or 1).
Octet This refers to 8-bit binary number.
Subnet mask: It is a 32-bit value that allows
the recipient of IP packets to distinguish the
network ID portion from the host ID portion of
a given IP address.
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
IP Address Format
Every IP address consists of two parts
namely:
Network portion and Host portion as
shown in the figure below:
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
NETWORK ID HOST ID
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IP Address Representation
In IPv4, the IP address is a 32-bit number.
The 32-bit number is represented as 4 octets
each separated by a dot.
E.g. 11000000 . 10101000 . 00000000. 00000010
For simplicity IP addresses are represented in a
decimal notation as 192.168.0.2
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Classes of IP Addresses In class-based IP addressing, there are five classes
namely:
Class A
Class B
Class C
Class D
Class E Out of these classes, only classes A,B and C are
considered usable by local Network Administrators.
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Usable IP Address Classes
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Class A IP Addresses - 1 Class A addresses are designed to support
extremely large networks.
A Class A IP address uses the first octet of the
address to indicate the network ID, and the
remaining three octets are used for the host
ID.
The first bit of a Class A address is always 0.
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Lowest number that can be represented is
00000000 (0).
The highest number is 01111111 (127).
However 0 and 127 are reserved and cannot
be used as a network address.
Any IP address that has a value between 1
and 126 inclusive in the first octet is a class Aaddress.
Class A IP Addresses - 2
Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
Class A IP Address
Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
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Class B IP Addresses - 1
The class B IP address was designed tosupport the needs of moderate to large-sized
networks.
A class B IP address uses two of the four
octets to indicate the network address and
the remaining two for the host addresses.
The first 2 bits of the first octet of a class B
address are always 10.
Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
Class B IP Addresses - 2
Lowest number that can be represented is
10000000 (128) and the highest number is
101111111 (191).
Any IP address that starts with a value in the
range of 128 to 191 inclusive in the first
octet is a Class B address.
Enterprise Network Management Lecture
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Class B IP Address
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Class C IP Addresses
The Class C address was designed to support
small network.
A Class C address begins with binary 110.
The lowest number that can be represented
is 11000000 (192) and the highest is
11011111 (223).
Any IP address that starts with a value in the
range of 192 to 223 inclusive in the first
octet is a Class C address.Enterprise Network Management Lecture
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Class C IP Address
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Usable IP Address Classes
CLASS FIRST OCTET DEFAULT S M SUPPORT
A 0 - 126 255.0.0.0 Very largeorganizations.
B 128 - 191 255.255.0.0 Medium-sizedorganizations
C192 - 223 255.255.255.0 Small
organizations
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Class D IP Addresses
This class of address was created to enablemulticasting in an IP address.
A multicast address is a unique network
address that directs packets that have the
destination address to predefined groups of IP
addresses.
The first 4 bits of a Class D address must be
1110.
The first octet range for Class D address is
11100000 to 11101111, or 224 to 239.Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
Class E IP Addresses
The IETF reserves the Class E address for its
own research.
This class of IP address is also referred to as
Experim ental Addresses.
The first 4 bits of a Class E address are always
set to 1.
The first octet range for Class E address is11110000 to 11111111, or 240 to 255.
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Private IP Addresses
Private IP addresses are assigned to an
organizations network by the local network
administrator.
Private IP addresses are not routable over the
Internet.
The range of IP addresses that are reserved
(RFC 1918) for private use are given in the next
slide.
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Range of Private IP Addresses
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Class Range of IP Addresses
A 10.0.0.0 to 10.255.255.255
B 172.16.0.0 to 172.31.255.255
C 192.168.0.0 to 192.168.255.255
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Public IP Addresses
Public IP addresses are required by
organizations that need to communicate with
the Internet.
Public IP addresses can be used to route traffic
in the public network.
Public IP addresses are assigned to
organizations by ISPs(Internet Service
Providers).
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.
Classless Inter Domain Routing(CIDR)
Its basically the method that ISPs use to allocate a
number of addresses to a company or a home
customer.
When you receive a block of addresses from an ISP,
what you get will look something like this:
192.168.10.32/28.
This is telling you what your subnet mask is.
The slash notation (/) means how many bits are turnedon (1s).
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Some CIDR Values
Subnet Mask CIDR Value
255.0.0.0 /8
255.128.0.0 /9
255.255.0.0 /16
255.255.192.0 /18
255.255.240.0 /20
255.255.255.0 /24
255.255.255.224 /27Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
NAT was introduced to slow the depletion ofavailable IP address space by allowing manyprivate IP addresses to be represented by somenumber of public IP addresses.
Situations when NAT is needed include:
You need to connect to the Internet and your hostsdont have globally unique IP addresses.
You change to a new ISP that requires you torenumber your network.
You need to merge two intranets with duplicateaddresses.
Network Address Translation (NAT)
Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
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Types of NAT
Static NAT: This is designed to allow a one-to-onemapping between local and global IP addresses.
Dynamic NAT: This gives you the ability to map anunregistered IP address to a registered IP addressfrom/out of a pool of registered IP addresses.
Overloading :This is designed to map multipleunregistered IP addresses to a single registered IP
address(many-to-one) by using different portnumbers.
It is also known as Port Address Translation(PAT).Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
Network Address Translation (NAT)
Enterprise Network Management Lecture
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Summary
An IP address uniquely identifies a node on a computernetwork.
In class-based IP addressing, only the first three(3)
classes are usable.
The remaining classes are reserved for special purposes.
Private IP addresses are not routable over the Internet
but public ones are.
ISPs use CIDR to allocate a number of addresses to a
company or a home customer.
NAT makes it easier and less expensive in connecting
LANs to the Internet.Enterprise Network Management Lecture
Slides by: Max well Dorgbefu Jnr.
End of Lecture !!!
Do Not Miss Next Weeks Lecture
on Network Mgt . Models.
Questions & Comments ???.....
Enterprise Network Management Lecture Slides by: Maxwell Dorgbefu Jnr.