LOOPBACK ADDRESSPARMINDER SINGH

ASSISTANT PROFESSOR| CHANDIGARH ENGINEERING COLLEGE,LANDRAN

SINGH.PARMINDER06@GMAIL.COM

CONTENTS

PURPOSE

The proclaim of this topic is to remind the Loopback addresses in networking.

This presentation update the knowledge of network users including to testing

the standalone machine (i.e. End user machine) and Network Layer devices

(Such as Router , Switches). The Topic had discussed by many authors but my

aim is to scrutinize the topic with practical layout using CISCO Packet Tracer.

LOOPBACK ADDRESS

Loopback address is an logical IP addressing that is nominating to only one

endpoint.

The addressing is to ensuring that the network has been properly working.

The loopback address does not support any extra hardware.

The messages doesn't flow outside the network; It has been generating by only

one machine and rerouted by the NIC (Network Interface Card);

LOOPBACK ADDRESS (CONT..)

The range of the Loopback addresses is 127.0.0.1 through 127.255.255.255.

The Loopback address test the Internet Protocol (IP)Stack Functionality.

The IP Stack is an implementation over computer networking protocol suite

(read TCP/IP Stack).

COMMAND

The command is any type of instruction to a computer or device.

The “ping” command is used to verifying the Loopback address.

Ping uses ICMP (Internet Control Message protocol) to send messages to target

machine for connectivity purpose.

If the target machine respond to the sender machine that means both

machines connected to each other.

DEVICES

The number of devices have been use for checking Loopback address on

the machines.

These devices can be categorized as:

Personnel Computer (PC)

Switch (SW)

Router (R)

PERSONNEL COMPUTER

The Personnel computer (PC) is an End User device where the user performing

number of tasks.

To verify the device (PC), whether the NIC card performing accurately; we are

using Loopback address 127.0.0.1

c:/> ping 127.0.0.1

This address ping the NIC Card and this card check the functionality of IP Stack.

This Loopback address restricted to PC only.

The Practical layout of this Loopback address shown in next slide.

Loopback address

PERSONNEL COMPUTER (CONT..)

First of all I am checking the IP and

MAC address of my PC by using

“ipconfig/all” command.

Now, I am using ping command with

loopback address 127.0.0.1.

Ping uses ICMP (Internet Control

Message protocol) protocol to reply on

the same system.

It seams that the functionality of the

PC was ‘ok’.

PERSONNEL COMPUTER (cont..)

The loopback address always ping to the NIC card for verifying the IP stack

functionality.

You can use Loopback address 127.9.0.2; This address does not ping to NIC

card else it verify only IP stack functionality.

c:/> ping 127.9.0.2

This address exclusively used for the reason of:

When NIC card not attached or missing on your PC.

If the NIC card not properly worked.

SWITCH

The Switch is Layer 2 Device that connects number of Pc’s according to the

availability of the Ethernet ports.

The switch performed on MAC address; it does not verified logical addresses.

It performs filtering and switching only on MAC (Medium Access Control)

addresses.

The Switch has unicasting feature; the sender send unicast message to the

destination machine and destination machine unicastly reply.

The Switch employ MAC Table to forwards the data from one device to another.

SWITCH(CONT..) The following steps need to configure the loopback

address :

Activate the loopback address on the interface by

using command “interface loopback number”

The range of number is 0 to 2147483647.

Assign IP address.

To active the link therefore You have to active the

interface by using command “no shutdown”.

Enter the ping command with assigned IP address.

Test the connectivity ; if the success rate is 100

percent then your Switch will be functioning

properly.

ROUTER

Router is a Network Layer device that forwards packet in to the Network.

This Network Supposed to be either LAN, MAN or WAN.

The Router is also acting as a Gateway for associates two different network.

The Router employing ICMP (Internet Control Message Protocol) Protocol for communes

different devices and nodes.

This Protocol helps the router to create routing table and configure best route path in between

two communicating nodes.

Router provides quality of service (QOS) feature performance.

Router Extends the network as a platform for cloud computing.

ROUTER(CONT..)The following steps need to configure the loopback

address :

Activate the loopback address on the interface by

using command “interface loopback number”

The range of number is 0 to 2147483647.

Assign IP address.

To active the link therefore You have to active the

interface by using command “no shutdown”.

Enter the ping command with assigned IP address.

Test the connectivity ; if the success rate is 100

percent then your router will be functioning properly.

REFERENCES

[1] https://www.netacad.com

[2] www.packettracernetwork.com

Questions?

SINGH.PARMINDER06@GMAIL.COM