Encapsulation

Encapsulation

Layered protocol models rely on encapsulation, which allows one protocol to be used for relaying another's messages.

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Encapsulation, closely related to the concept of Protocol Layering, refers to the practice of enclosing data using one protocol within messages of another protocol.To make use of encapsulation, the encapsulating protocol must be open-ended, allowing for arbitrary data to placed in its messages. Another protocol can then be used to define the format of that data.

Encapsulation Example

For example, consider an Internet host that requests a hypertext page over a dialup serial connection. The following scenario is likely:
First, the HyperText Transfer Protocol (HTTP) is used to construct a message requesting the page. The message, the exact format of which is unimportant at this time, is represented as follows:



Next, the Transmission Control Protocol (TCP) is used to provide the connection management and reliable delivery that HTTP requires, but does not provide itself. TCP defines a message header format, which can be followed by arbitrary data. So, a TCP message is constructed by attaching a TCP header to the HTTP message, as follows:

Now TCP does not provide any facilities for actually relaying a message from one machine to another in order to reach its destination. This feature is provided by the Internet Protocol (IP), which defines its own message header format. An IP message is constructed by attaching an IP header to the combined TCP/HTTP message:

Finally, although IP can direct messages between machines, it can not actually transmit the message from one machine to the next. This function is dependent on the actual communications hardware. In this example, we're using a dialup modem connection, so it's likely that the first step in transmitting the message will involve the Point-to-Point Protocol (PPP):

Note that I've drawn the PPP encapsulation a little differently, by enclosing the entire message, not just attaching a header. This is because PPP may modify the message if it includes bytes that can't be transmitted across the link. The receiving PPP reverses these changes, and the message emerges intact. The point to remember is that the encapsulating protocol can do anything it wants to the message - expand it, encrypt it, compress it - so long as the original message is extracted at the other end.

DoD Networking Model

DoD Networking Model

The first layered protocol model we will study is the 4-layer DoD Model. This is the model originally designed for the Internet, and is important because all of the Internet's core protocols adhere to it.

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The Department of Defense Four-Layer Model was developed in the 1970s for the DARPA Internetwork Project that eventually grew into the Internet. The core Internet protocols adhere to this model, although the OSI Seven Layer Model is justly preferred for new designs.
The four layers in the DoD model, from bottom to top, are:

1. The Network Access Layer is responsible for delivering data over the particular hardware media in use. Different protocols are selected from this layer, depending on the type of physical network.
2. The Internet Layer is responsible for delivering data across a series of different physical networks that interconnect a source and destination machine. Routing protocols are most closely associated with this layer, as is the IP Protocol, the Internet's fundamental protocol.
3. The Host-to-Host Layer handles connection rendezvous, flow control, retransmission of lost data, and other generic data flow management. The mutually exclusive TCP and UDP protocols are this layer's most important members.
4. The Process Layer contains protocols that implement user-level functions, such as mail delivery, file transfer and remote login.

Cisco Menu

1: OSI Reference Model

2: DoD Networking Model

3: Encapsulation

4:|Subnetting

5:EIGRP Routing Protocol !

6:EIGRP

OSI Reference Model

What is OSI Model?

The OSI Model is used to describe networks and network application.

Layers of OSI  Model 

Three are Sever Layers of OSI Model :

OSI Layer Diagram:

  

7)  Application Layer : The application layer provider different services to the application. Example of services provided by this layer are file transfer, electronic messaging e-mail, virtual terminal access and network management.

6) Presentation Layer : The Presentation layer is responsible for protocol conversion, date encryption/decryption, Expanding graphics command and the date compression. This layer makes the communications between two host possible.

5) Session Layer : This layer is responsible for establishing the process-to-process communication between the host in the network. This layer is responsible for establishing and ending the sessions across the network. The interactive login is an example of services provided by this layer in which the connective are re-connected in care of any interruption.

4) Transport Layer : This layer is responsible for end-to-end delivers of messages between the networked hosts. It first divides the streams of data into chunks or packets before transmission and  then the receiving computer re-assembles the packets. It also guarantee error free data delivery without loss or duplications.

3) Network Layer : This layer is responsible for translating the logical network address and names into their physical address ( MAC address). This layer is also responsible for addressing, determining routes for sending and managing network problems such as packet switching, data congestion and routines.

2) Data Link Layer : Data link layer is responsible for controlling the error between adjacent nodes and transfer the frames to other computer via physical layer. Data link layer is used by hubs and switches for their operation.

1) Physical Layer : Physical  Layer is responsible for transmitting row bit stream over the physical cable. The physical layer defines the hardware items such as cables, cards, voltages etc.

How to remember the layer of OSI model?

The easiest way to remember the different layers of OSI Model is to use the mnemonic "All people seem To need Data Processing":

Layer	Name
Mnemonic
7	Application	All
6	Presentation	People
5	Session	Seem
4	Transport	To
3	Network	Need
2	Data Link	Data
1	Physical	Processing

Menu 2003 server

1: Installation 2003 server

Windows 2003 installation

Windows Server 2003 system requirements.

There are different editions of serve 2003 it depends which edition you have planned to install

Windows Server 2003 Edition	Number of Processors	Processor Speed	RAM	Available Disk Space (for Setup)
Web	1–2	133 megahertz (MHz) minimum; 550 MHz recommended	128 megabytes (MB) minimum; 256 MB recommended; 2 GB maximum	1.5 gigabytes (GB)
Standard	1–4	133 MHz minimum; 550 MHz recommended	128 MB minimum; 256 MB recommended; 4 GB maximum	1.5 GB
Enterprise	1–8	133 MHz minimum; 550 MHz recommended	128 MB minimum; 256 MB recommended; 32 GB maximum	1.5 GB
Datacenter	8–32	400 MHz minimum	512 MB minimum; 64 GB maximum	1.5 GB

Now we are going see how to install Server 2003 Standard Edition.

Insert a boot disk in a CD/DVD rom boot the system from CD,

Press any key to boot form CD.

Set up will load minimum drives from CD.

Press enter key (↵) to run Setup.

Agree the licensing agreement by press F8 to agree.

Delete the existing partition & create a new partition.

Format the partition.

Set up will format the partition to install windows.

Now Setup Will copy files required for installation.

After copying the system will restart automatically.

After restarting Setup will prepare to install.

At this point of time your Screen might flicker your keyboard & mouse may not work for some movement.

It will ask for regional settings don’t worry leave default click on Next.

Give the name & Organizing click on Next.

Enter the product key which you will be provided by Microsoft.

This will ask you how clients & servers are connected to your network so it will keep track or license of your clients & Server.

Now it will prompt for computer Name & to set the password click on Next.

Set the Date & Time Zone & click on Next.

Select the typical for standalone select custom for Network configuration.

Select Internet Protocol (TCP/IP) click on properties.

Give an IP address of your network click on ok.

Click on next to finish the wizard.

If you have a domain controller give the domain name to join this serve to domain.

It will prompt for user credential type the user name & password it will be joined to domain click o next & finish the wizard.

None for a while the setup will complete.

After completing the system will restart.

This is how the server installation is desktop systems of workstations systems.

Desktop                                                          Workstation

In Servers you will be provided a Driver CD or a Floppy, first You need to Configure RAID than boot form driver CD of a Floppy follow up the wizard than it will ask you the server 2003 CD to insert in CD\DVD, you can configure RAID even after installation of server.

Server

2008 SERVER MENU

1: Installation 2008 server!

2: Active Directory Installation!

3: Active Directory !

4: Installing DNS Server in windows 2008 !

5:- DHCP INSTALLATION !

6:- Child Domain!

7:- Additional Domain Controller!

8:- IIS Server 7.0 Windows 2008

9:- Installing & Configuring NAT

10:- Read Only Domain Controller

2008 Installation

Upgrade notes:

I will not discuss the upgrade process in this article, but for your general knowledge, the upgrade paths available for Windows Server 2008 shown in the table below:

If you are currently running:	You can upgrade to:
Windows Server 2003 Standard Edition (R2, Service Pack 1 or Service Pack 2)	Full Installation of Windows Server 2008 Standard Edition Full Installation of Windows Server 2008 Enterprise Edition
Windows Server 2003 Enterprise Edition (R2, Service Pack 1 or Service Pack 2)	Full Installation of Windows Server 2008 Enterprise Edition
Windows Server 2003 Datacenter Edition (R2, Service Pack 1 or Service Pack 2)	Full Installation of Windows Server 2008 Datacenter Edition

Follow this procedure to install Windows Server 2008:

1. Insert the appropriate Windows Server 2008 installation media into your DVD drive. If you don't have an installation DVD for Windows Server 2008, you can download one for free from Microsoft's Windows 2008 Server Trial website.

2. Reboot the computer.

3. When prompted for an installation language and other regional options, make your selection and press Next.

4. Next, press Install Now to begin the installation process.

5. Product activation is now also identical with that found in Windows Vista. Enter yourProduct ID in the next window, and if you want to automatically activate Windows the moment the installation finishes, click Next.

If you do not have the Product ID available right now, you can leave the box empty, and click Next. You will need to provide the Product ID later, after the server installation is over. Press No.

6. Because you did not provide the correct ID, the installation process cannot determine what kind of Windows Server 2008 license you own, and therefore you will be prompted to select your correct version in the next screen, assuming you are telling the truth and will provide the correct ID to prove your selection later on.

7. If you did provide the right Product ID, select the Full version of the right Windows version you're prompted, and click Next.

8. Read and accept the license terms by clicking to select the checkbox and pressing Next.

9. In the "Which type of installation do you want?" window, click the only available option –Custom (Advanced).

10. In the "Where do you want to install Windows?", if you're installing the server on a regular IDE hard disk, click to select the first disk, usually Disk 0, and click Next.

If you're installing on a hard disk that's connected to a SCSI controller, click Load Driver and insert the media provided by the controller's manufacturer.

If you're installing in a Virtual Machine environment, make sure you read the "Installing the Virtual SCSI Controller Driver for Virtual Server 2005 on Windows Server 2008"

If you must, you can also click Drive Options and manually create a partition on the destination hard disk.

11. The installation now begins, and you can go and have lunch. Copying the setup files from the DVD to the hard drive only takes about one minute. However, extracting and uncompressing the files takes a good deal longer. After 20 minutes, the operating system is installed. The exact time it takes to install server core depends upon your hardware specifications. Faster disks will perform much faster installs… Windows Server 2008 takes up approximately 10 GB of hard drive space.

The installation process will reboot your computer, so, if in step #10 you inserted a floppy disk (either real or virtual), make sure you remove it before going to lunch, as you'll find the server hanged without the ability to boot (you can bypass this by configuring the server to boot from a CD/DVD and then from the hard disk in the booting order on the server's BIOS)

12. Then the server reboots you'll be prompted with the new Windows Server 2008 type of login screen. Press CTRL+ALT+DEL to log in.

13. Click on Other User.

14. The default Administrator is blank, so just type Administrator and press Enter.

15. You will be prompted to change the user's password. You have no choice but to press Ok.

16. In the password changing dialog box, leave the default password blank (duh, read step #15…), and enter a new, complex, at-least-7-characters-long new password twice. A password like "topsecret" is not valid (it's not complex), but one like "T0pSecreT!" sure is. Make sure you remember it.

17. Someone thought it would be cool to nag you once more, so now you'll be prompted to accept the fact that the password had been changed. Press Ok.

18. Finally, the desktop appears and that's it, you're logged on and can begin working. You will be greeted by an assistant for the initial server configuration, and after performing some initial configuration tasks, you will be able to start working.

Next, for the initial configuration tasks please follow my other Windows Server 2008 articles found on the Related Windows Server 2008 Articles section below.

For Official Microsoft information on Windows Server 2008, see the Windows Server 2008 homepage.