Difference between classful and classless addressing in IPV4

This document explains the difference between classful and classless addressing in IPV4. It discusses how classful addressing uses fixed classes to allocate IP addresses, while classless addressing allows for more flexibility in network ID allocation. The document also explores the reasons why most organizations don't want a block C class due to its limited number of addresses. Other topics covered include subnetting, network address translation (NAT), connection-oriented and connectionless services, fragmentation, transition strategies from IPV4 to IPV6, addressing mapping protocols, ICMP, autonomous systems, RIP, BGP, and the contrast between distance vector and link state routing.

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1. Difference between classful addressing and classless addressing in IPV4.
Classful addressing make use of classes in allocating IP address. It is divided into 5 classes
where only three of the classes are mainly used. Each class has a fixed number of blocks which
have a fixed number of IP addresses (Tomsho, 2016). In classless addressing there is no
predefined number of network id and any number of bits can be used as network ID
2. Reason why most of class A address are wasted and why most organization don’t want
a block C class.
Class A has an eight bit prefix meaning it had more than 16 million address. The number of the
address is too big to be used for one organization and the remaining addresses could not be
allocated to other organization because there network belongs to another organization (Charles,
2015). Most organization opt to not to use class C because of its small number of address. Class
C has 255 address which is too small for large organization with more than 255 computers.
3. What is a mask
A mask is a 32 bit IP address which divides the IP address into two IP address the network
address and the host address each having defined number of bits (Tomsho, 2016).
4. What is network address? And how can we find a network address if one of the address
in the block is known
Network address is part of an IP address used to identify the network where the computer
assigned the address is located. The network address communicate with all networks connected
to a single network. Network address is found by ANDing the mask and the IP address (Tomsho,
2016).
5. What is Subnetting and how does subnet mask differ from default mask
Subnetting a way of dividing large network into small logical networks (Charles, 2015). Subnet
mask is used to differentiate the network part and the host part of the IP address and has
consecutive 1s bits which are more than those of default mask.
6. What is NAT and how can NAT help in IP depletion
NAT stand for Network Address Translation and mostly it is used in routers to translate set of IP
address to another set of IP address. Due to limited number of public IP address NAT can be
used to translate the private IP address to public IP addresses to prevent public IP exhaustion.
7. Difference between a connectionless and connection oriented services
Connection-oriented services are service that establish a connection before the data is sent to its
destination (Charles, 2015). This kind of protocols are designed to provide a reliable
communication in a complex internetworks (Tomsho, 2016). In connectionless the data are sent
to destination end without establishing a connection (Charles, 2015). Connectionless service are
designed to provide an efficient communication of data (Tomsho, 2016).

8. Define fragmentation and why it is needed
Fragmentation is the process of breaking a large datagram/packet into small datagrams/packets.
Fragmentation is needed when a large packet of data is sent to small MTU network. MTU is the
maximum transfer unit it define the maximum number of bytes to be sent (Alex, 2010).
9. Transition strategy to move from IPV4 to IPV6
Moving from IPV4 to IPV6 would not happen on a specific day but it is a continuation process
that will happen continue for years.
 Dual stack architecture
 IPv6 over IPv4
 Intra-Site Automatic Tunnel Addressing Protocol
In dual stack computer run both IPV4 and IPV6 and computer use native packets types to
communicate to both IPV4 and IPV6. The IPV6 packets are encapsulated in IPV4 header on
computers using both the IPV4 and IPV6 (Tomsho, 2015), while tunneling transmit IPV6 packet
over IPV4 packets on computer using IPV6 (Tomsho, 2015).
10. Common addressing mapping protocols and how they are used.
Address Resolution Protocol (ARP) used to map IP address to Mac Address
Revised Addressing Resolution Protocol (RARP) can be used in locating the logical address for
computer that only knows its physical address. Is used when computer connect to the network for
the first time.
Bootstrap protocol (BOOTP) can be used to map physical address to logical address.
Dynamic Host Control Protocol use to assign IP addressing automatically to a computer when is
connected to new network (Oliver, 2017).
11. What is ICMP and why do we need it
Internet Control Message Protocol is used to by network device to send error and query message
between devices (Oliver, 2017). The ICMP is important because it can be used to determine if
routers or host devices are still alive.
12. What is autonomous system
Autonomous system are collection of networks and routers under the control of a common
network administrator (Tomsho, 2015).
13. The purpose of RIP
RIP stands for Routing Information Protocol. It is a simple distance vector protocol. Its purpose
is to choose the shortest path required to send or receive data packet by use of hop count
(Tomsho, 2015).

14. Function of RIP message
ARIP message is used by nodes in distance vector routing to share and update its knowledge to
neighboring nodes or to receive and request routing information of the autonomous system.
15. Why do OSFP message propagate faster than RIP messages
In OSFP autonomous system is divided into many areas with connected networks. Routers inside
the area flood the network with routing information and any changes of its neighboring network,
for this reason OSFP message are propagated immediately. In RIP a periodic update occurs
every thirty second (30s) to carry any update from one node to another (Oliver, 2017).
16. What is the purpose of BGP
According to Tomsho (2015) BGP is used to route between autonoumous system and in its
configuration parameter it includes an AS number. BGP is mostly used by ISP because it can
analyze the features of an autonomous system .
17. Contrast and comparison between distance vector routing against link state routing
In Distance vector routing nodes share information about an internetwork with neighboring
nodes by copying a routing table to others nodes. In link state routing nodes share information by
sending status of their interface links with other nodes in same network (Tomsho, 2015).
Distance vector use metrics based on heap count, bandwidth of the link, delay, congestions to
determine the best path while link state routing use metric based on link speed which help in
making best choice in complex internetworking (Tomsho, 2015).

References
Alex, S. (2010). Fragmentation & Addressing. Computer Networks .
Charles, S. (2015). introduction to networking. MIAMI: Creative Commons Attribution.
Oliver, I. (2017). Fundamentals of Data Communication Networks. Boston: Wiley & Sons.
Tomsho, G. (2015). Guide to Networking Essentials (7th ed.). Boston: Cengage Learning.