USING OSPF ROUTING

SIMULATION OF DATA TRAFFIC CONTROL

Objective

To design a network for a software development organization based on OSPF. The organization has three departments, development, testing and trainee and a high speed internet connection. The trainee department should not have access to internet browsing, but all other communication should be allowed on the internet. The users in all the departments should have inter-access communication with each other. All the departments should be on different IP networks.

Requirements

Design different area of the network.Core knowledge of subnet mask and wild

mask. Cisco based routers and switches to be used. Identify the configurations required on the

routers and switches for the open routing protocol.

Introduction to computer networks

Three types of networksLAN: privately owned and links the devices in a

single office, building, or campus.MAN: designed to extend over an entire city. It

may be single network such as a cable television network, or it may be a means of connecting a number of LANs into a larger network

WAN: provides long-distance transmission of data, image, audio, and video information over large geographic areas that may comprise a country, a continent, or even the whole world

Classes of Routing Protocols

Routing protocol is used between router to determine paths and maintaining the routing tables. Processes for sharing route information allow routers to communicate with other routers to update and maintain the routing tables.RIP, IGRP, OSPF, BGP,And EIGRP

Comparing Routing Protocols

 

DISTANCE VECTOR ROUTING

 

LINK STATE ROUTING

a) View network topology from neighbor’s perspective.

b) Adds distance vector from router to router.

c) Frequent periodic updates.

Slow convergence.

d) Passes copies of routing table to neighbor router.

a) Gets common view of entire network topology.

b) Calculate the shortest path of other router.

c) Event-triggered updates.

Fast convergence.

d) Passes link-state routing updates to other router.

Routing Information Protocol

RIP adheres to the following Distance Vector characteristics:RIP sends out periodic routing updates (every

30 seconds).RIP sends out the full routing table every

periodic update.RIP uses a form of distance as its metric (in

this case, hopcount of 15).RIP uses the Bellman-Ford Distance Vector

algorithm to determine the best “path” to a particular destination.

Version 1 (RIPv1) and Version 2 (RIPv2).

 

RIPv1

 

RIPv2

• Classful

• Does not include the subnet mask with its routing table updates

• Does not support Variable Length Subnet Masks (VLSMs)

• Networks must be contiguous, and subnets of a major network must be configured with identical subnet masks

• Sends updates as broadcasts to address 255.255.255.255

• Classless

• Does include the subnet mask with its routing table updates

• RIPv2 fully supports VLSMs

• Discontinuous networks and varying subnet masks can exist.

• Routing updates are sent via multicast, using address 224.0.0.9

OSPF (Open Shortest Path First) Routing Protocol

The Open Shortest Path First or OSPF protocol is an intra-domain routing protocol based on link state routing. Its domain is also an autonomous system. To handle routing efficiently and in a timely manner, OSPF divides an autonomous system into areas. An area is a collection of networks, hosts, and routers all contained within an autonomous system. All the areas must be connected with each other.

An Autonomous System

Types of links

Point-to-point: one router attached to the otherTransient: network with several routers attached to itStub: a network that is connected to only one router. Link is only one-directional, from the router to the networkVirtual: When the link between two routers is broken, the administration may create a virtual link between them, using a longer path that probably goes through several routers.

Various Links

OSPF and RIP Comparison

 

Characteristics

 

OSPF

 

RIPv1

 

RIPv2

 Type of protocol

 Link State  Distance Vector

 Distance Vector

 Classless Support

Yes Yes No

 VLSM Support

Yes Yes No

Route Propagation

 Multicast on change

 Periodic multicast

 Periodic Broadcast

 

Path Matric

 

Bandwidth

 

Hops

 

Hops

 Hop count limit

None  15  15

 Convergence

 Fast  Slow  Slow

Access Control List

ACLs are lists of conditions that are applied to traffic traveling across a router's interface. 

These lists tell the router what types of packets to accept or deny based on some conditions

ACLs can be configured at the router to control access to a network or subnet.

Some ACL decision points are source and destination addresses, protocols, and upper-layer port numbers.

Reasons to Create ACLs

Limit network traffic and increase network performance.

Provide traffic flow control. Provide a basic level of security for network access. Decide which types of traffic are forwarded or

blocked at the router interfacesFor example: Permit e-mail traffic to be routed, but

block all telnet traffic. There are of two typesStandardExtended

CASE STUDY

The Tata Steel Company has all Cisco routers connected in the network. The network administrator Robert requires configuring the router of the HR Department to disable the traffic from all the host of the subnet 1272.168.2.6 from the Network 40.0.0.1 and for 20.0.0.2 host for security purpose and the company has web secure and the organization want only the specific department users can access the web server.Problem: Network administrator already configures the

organization network than he has to again configure the access-list as per requirement.

Solution: Firstly we will draw a network on packet tracer. According to the requirement of the administrator.

Problem Scenario

RIP OVER OSPF

Network Area of OSPF

The following are the reasons for creating OSPF in a hierarchical design:To decrease routing overheadTo speed up convergenceTo confine network instability to single area of

the network.OSPF must have an area 0 or BACKBONE, and all other areas should connect to this area. There are various kinds of routers like: internal, boundary area, etc. and various areas like: boundary, regular, stub areas, etc.

OSPF OVER RIP

Implementing ACLs

Now we will implement the Extended ACL for Blocking the Server for the particular host on Router 0.

Router#enRouter#conf tEnter configuration commands, one per line. End with CNTL/Z.Router(config)#access-list 100 deny tcp host 20.0.0.2 host

172.167.2.6 eq 80Router(config)#access-list 100 permit tcp any anyRouter(config)#access-list 100 permit icmp any anyRouter(config)#int fastEthernet 7/0Router(config-if)#ip access-group 100 inRouter(config-if)#no shutRouter(config-if)#exRouter#%SYS-5-CONFIG_I: Configured from console by console

Continued

Now we will implement the Extended ACL for Blocking the Server for the particular Network on Router 0.

Router#enRouter#conf tEnter configuration commands, one per line. End with CNTL/Z.Router(config)#access-list 100 deny tcp host 40.0.0.1 host

172.167.2.6 eq 80Router(config)#access-list 100 permit tcp any anyRouter(config)#access-list 100 permit icmp any anyRouter(config)#int fastEthernet 0/0Router(config-if)#ip access-group 100 inRouter(config-if)#no shutRouter(config-if)#exRouter#%SYS-5-CONFIG_I: Configured from console by console