Packet Switching

Packet Switching

•          Data transmitted in small packets

–        Typically 1000 octets

–        Longer messages split into series of packets

–        Each packet contains a portion of user data plus some control information

–        Control information

–        Routing (addressing) information

–        Packets are received, stored briefly (buffered) and passed on to the next node

Store and forward

 

Switching Technique

•          Station breaks long message into packets

•          Packets sent one at a time to the network

•          The two types of packet switching are:

–        Datagram packet switching

Virtual circuit packet switching

Features of Datagram Packet Switching

•          Each packet is treated independently

•          Packets can take any practical route

•          Packets may arrive out of order

•          Faster delivery to destination

•          Alternate rooting on node failure

Suitable for short messages

Virtual Circuit Packet Switching

•          Preplanned route established before any packets sent

•          Call request and call accept packets establish connection (handshake)

•          Each packet contains a virtual circuit identifier instead of destination address

•          No routing decisions required for each packet

•          No dedicated path

Virtual circuit packet switching

Circuit Switching

                                                        Switching

The process of sending data to  the appropriate   

        port                  

The two different switching technologies are

   (1) Circuit switching 

  (2)  Packet switching

Circuit Switching - Features

•          Dedicated communication path between two stations

•          Three phases

–        Establish

–        Transfer

–        Disconnect

–        Must have switching capacity and channel capacity to establish connection

•          Must have intelligence to work out routing

•          Inefficient

•          Channel capacity dedicated for duration of connection

–        If no data, capacity wasted

–        Set up (connection) takes time

•          Once connected, no delay in data transfer

•          Suitable for voice (phone), large volume continuous traffic

Disadvantages of Circuit Switching

•          Circuit switching is designed for only voice

•          Resources dedicated to a particular call

•          Much of the time data connection is idle

•          Data rate is fixed

•          Both ends must operate at the same rate

Switching

Advantages of Switching, Diff b/w switching and non switching

Circuit Switching

Lab Practicals: INSTALLING OF NIC CARD

                                                                         INSTALLING OF NIC CARD

AIM: 

Installing of NIC card (Network Interface Card)

APPARATUS:-

NIC card,

PCI (Peripheral Component Inter connection)

Procedure:

Identify the PCI slot on mother board.

Identify the cut on the PCI slot

Take the NIC CARD AND Identify cut on it

Now insert the NIC Card into the PCI SLOT

Carefully handle such that cuts of NIC card and PCI slot must match.

Result

Thus NIC card is installed.

                            Note: 

No need to write into the record book just read about the NIC Card:

Definition:

      A network interface card (NIC) is a computer circuit board or card  that is installed in a computer so that it can be connected to a network. 

          Personal computers and workstations on a local area network (LAN) typically contain a network interface card specifically designed for the LAN transmission technology, such as Ethernet or token ring. Network interface cards provide a dedicated, full-time connection to a network. Most home and portable computers connect to the Internet through as-needed dial-up connection. The modem  provides the connection interface to the Internet service provider.

           In new computers, many NICs are now pre-installed by the manufacturer. All NICs feature a speed rating such as 11 Mbps, 54 Mbps or 100 Mbps that suggest the general performance of the unit.

Some NIC cards work with wired connections while others are wireless. Most NICs support either wired Ethernet or WiFi wireless standards. Ethernet NICs plug into the system bus of the PC and include jacks for network cables, while WiFi NICs contain built-in transmitters / receivers (transceivers).