Application layer: It is the layer 7th of OSI model. Its 
provide user interface that user used to interact with 
software application (IE, Opera).

Apart from this, the other key functions performed by 
application layer is - 
a) Identify & Establish Communication.
b) Determine Resource Availability.
c) Synchronize Communication.

Suppose u want to access www. yahoo.com. To accomplish this 
task, u write www.yahoo.com on address bar. Now Internet 
Explorer with the help of protocol give u the necessary 
interface to access Yahoo web page.

U can take another example, Windows Media player. We can 
play music thro Win Media player. At this time, application 
layer privide necessary interface to play a song thro media 
player. 


a) Identify & Establish Communication - Application 
identify & determine the communication partner with whom 
its goin to transfer data.

When u press enter after write www.yahoo.com, the 
application layer determine wheater its a valid URL or not. 
If yes, its establish a communication with server where 
this page reside. 

b)Determine Resource Availability: Application must 
determine wheather the sufficient network resources are 
available or not for the requested communication.

Application layer determine wheather the yahoo web page is 
present on the world wide web or not. Application layer 
make sure it.

c) Synchronize Communication: Communication between 
application need certain help which is provided by 
application layer.

Communication between ur system n web server need certain 
help, which is provided by application layer.



If somebody explain more in depth, i'll be thankful to 
him/her. thanks in advance...

 If we just write this web address on address bar & Press 
ENTER,As far as my concern, Protocol Used in this case -

a) HTTP
b) WWW
c) DNS

All 7 layers will involve in this process. 

If I m wrong, plzzzz let me knw wats right. I'l be thankful to 
u. 

HTTP
HTTPS
WWW
DNS
POP3
IMAP4
FTP
X.400
SMPT
are used ant this message to go through all 7layers os OSI 
model

DNS
UDP/TCP over IP (Assuming that you are 
HTTP
In IP you dont have 7 layers. Your browser is at 
Application layer. Below that you have Physical, Data link, 
Network and Transport layers.

WWW is not a protocol. :)

HTTPS : This is not a secure link

as a customer service employee you can never abuse a 
customers, if he/she starts that asked them polietly whats 
the problem actually and solve satisfactorily even then 
they are unable to satisy then plz forward this call to u r 
higher employee r team lead r project lead....but as 
employee u cannot abuse any customer....this is the first 
lesson taught to employee in bussiness field..

1.request
2.indication
3.response
4.confirmation

there are 7 layers in osi reference model.
1.physical layer
2.data link layer
3.network layer
4.transport layer
5.session layer
6.presentation layer
7.application layer

ISO seven layer model
1: Physical layer 
moves bits using voltage, current, light, etc. 
2: Data Link layer 
bundles bits into frames and moves frames between hosts on 
the same link 
3: Network layer (e.g. IP) 
Makes routing decisions 
uses destination address in packet 
Forwards packet hop by hop 
encapsulates network layer packet inside data link layer 
frame 
different framing on different underlying network types 
Unreliable 
Single address space for the entire internetwork
4: Transport layer (e.g. TCP) 
end to end transport of datagrams 
encapsulates datagrams in network layer packets 
adds reliability by detecting and retransmitting lost 
packets 
uses acknowledgements and sequence numbers to keep track
5: Session layer 
not used in the TCP/IP network model 
6: Presentation layer 
not used in the TCP/IP network model 
7: Application layer 
Uses the underlying layers to carry out work

7 layers we will start from bottom
  1. physical layer
  2. data link layer
  3. network layer
  4. transport layer
  5. session layer
  6. presentation layer
  7. application layer

Hi this shyam mohan.M


Go to command promote and type (ipconfig /all) in that 
physical adress.  physical adress nothing but a mac adress.

This is Venu.b


We can't change the MAC address of system. It's uniq. It's 
created by manifacturer by the time of Manifacturing.

Physically we can change the MAC address but logically we 
can change the MAC address

In linux, you can change the hardware (MAC) address of your 
machine.This is how it is done.I'am aware about windows.


# ifconfig eth0 down
# ifconfig eth0 hw ether 00:80:48:BA:d1:20
# ifconfig eth0 up
# ifconfig eth0 |grep HWaddr
it done!!!

POD Ping of Death, ping is and ICMP protocol normally it’s 
use send and receive 64bytes , increasing this ICMP bytes 
from 64 to 65,535 it call Ping Death , Generally It is ICMP 
Ping Attack in security World

set of rules to transmit data from one system to another
system anywhere in network

protocol means set of rules & regulations...simply says 
that one

Protocals are the languages spoken by the devices on the 
network to communicate or share the information to each 
other

Usually wild card masking is used in access list and ospf 
configuration

You can prepare for SIP call flows and go through some of 
the SIP messages , different call scenarios , SIP message 
structure

In computer networking, DMZ is a firewall configuration for 
securing local area networks (LANs). 
In a DMZ configuration, most computers on the LAN run 
behind a firewall connected to a public network like the 
Internet. One or more computers also run outside the 
firewall, in the DMZ. Those computers on the outside 
intercept traffic and broker requests for the rest of the 
LAN, adding an extra layer of protection for computers 
behind the firewall. 

Traditional DMZs allow computers behind the firewall to 
initiate requests outbound to the DMZ. Computers in the DMZ 
in turn respond, forward or re-issue requests out to the 
Internet or other public network, as proxy servers do. 
(Many DMZ implementations, in fact, simply utilize a proxy 
server or servers as the computers within the DMZ.) The LAN 
firewall, though, prevents computers in the DMZ from 
initiating inbound requests. 

DMZ is a commonly-touted feature of home broadband routers. 
However, in most instances these features are not true 
DMZs. Broadband routers often implement a DMZ simply 
through additional firewall rules, meaning that incoming 
requests reach the firewall directly. In a true DMZ, 
incoming requests must first pass through a DMZ computer 
before reaching the firewall.

A DeMilitarised Zone (DMZ) is a seperate network located in 
the neutral zone between a private (inside) network and a 
public (outside) network

ARP-Adress Resolution Protocol[protocol no 14]
It is use to convert logical address i.e IP add to physical 
add i.e MAC add because sender and Rxr communication based 
on MAC add not IP add.