A simple simulation of ospf.

1. WORKING WITH OSPF ROUTING
PROTOCOL IN GNS3
VISHNU CP(16C110)
VIKASH JAIN(16C109)
PRASHANT JOSHI(16C061)

2. AREA : NETWORKS &
SECURITY
SUB AREA: NETWORKS &
TOPOLOGY
TOOL USED: GNS3.

3. INTRODUCTION

4. ROUTING PROTOCOL
A routing protocol specifies how
routers communicate with each other,
distributing information that enables
them to select routes between any two
nodes on a computer network.

5. OSPF
 Open Shortest Path First (OSPF) is a routing
protocol for Internet Protocol (IP) networks.
 It is an Interior Gateway Protocol(IGP).
 It uses a link state routing (LSR) algorithm.
 It is defined as OSPF Version 2 in RFC 2328 (1998)
for IPv4.
 The updates for IPv6 are specified as OSPF
Version 3 in RFC 5340 (2008)

6. WHAT MAKES OSPF DIFFERENT?
 Unlike other routing protocols, OSPF does not carry
data via a transport protocol, such as the User
Datagram Protocol (UDP) or the Transmission
Control Protocol (TCP).
 Instead, OSPF forms IP datagrams directly,
packaging them using protocol number 89 for the
IP Protocol field.
 It was designed to support variable-length sunbet
masking.

7. CONTD..
 It detects changes in the topology such as link
failures, very quickly and converges on a new loop-
free routing structure within seconds.
 An OSPF network may be structured or subdivided
into routing areas .
 It uses both unicast and multicast tosend packets
and link state updates.
 The OSPF protocol,when running on IPv4 ,can
operate securely between routers.

8. BASIC STEPS IN OSPF
o Become Neighbors
Two routers running OSPF on the same link agree to
form a neighbor relationship.
o Exchange database information
The neighbor routers swap their LSDB information
with each other.
o Choose the best routes
Each router chooses the best routes to add to its
routing table based on the learned LSDB information.

9. TOOL - GNS 3
 GNS 3(GRAPHICAL NETWORK SIMULATOR 3)
 IT IS A NETWORK SOFTWARE EMULATOR.
 ALLOWS COMBINATION OF VIRTUAL AND REAL
DEVICES TO SIMULATE COMPLEX NETWORKS.
 IT USES DYNAMIPS EMULATION SOFTWARE
USED TO SIMULATE CISCO IOS .

10. INSTALLATION
ITEM REQUIREMENT
Operating System Windows 7 (64 bit) or later
Processor 2 or more Logical cores
Memory 4 GB RAM
Storage 1 GB available space
(Windows Installation is <200MB).

11. DOWNLOAD GNS 3 AT
“https://gns3.com/"

12. CREATE A FREE ACCOUNT AND
DOWNLAOD

13. GNS 3 WORKSPACE : THIS IS THE CANVAS WHERE YOU CAN
CREATE YOUR NETWORK

14. To create your first GNS3 topology, first click on Switches in
the Devices Toolbar. Drag and drop the built-in ethernet
switch to the GNS3 Workspace as shown below.. An instance
of the device called Ethernetswitch-1 will now be available in
the topology.

15. Next, click on End devices in the Devices Toolbar, and drag
and drop an instance of VPCS (a simple PC simulator) into
the Workspace, which will be called PC-1: Add as many
VPCS as per your network

16. Click the Add a Link button to start adding links to your topology.
The mouse cursor will change to indicate that links can be
added:

17. Click on PC-1 in your topology to display available interfaces. In
this example, only Ethernet0 is available (this is device
dependent):
Click Ethernet0 on PC-1, and then left-click on Ethernetswitch-1:

19. Reference paper : A Study And Analysis on Computer Network
Topology For Data Communication-Santanu Santra, Pinaki Pratim
Acharjya

20. How a simple topology looks like.

21. OSPF IN IPV4

33. REFERENCE
•Implementation of Open Shortest Path First
Version 3 (OSPFv3) with Encryption and
Authentication in IPv6 Network
Author: Rahul Sharma
Nishi Yadav,Springer,2019
•www.gns3.com