Internet working is based on the connections of computer network with other networks through use of gateways that gives a information about method of routing. We can define internet-working as the result of inter connected system. Internet is the smallest example of internet working. It connects disparate types of available networking technology. Internet Working is the commonly asked topics as per Interview for Computer Science Students. Here we have tried to made available some useful Internet Working Interview Questions and Answers to help students in order to prepare for their examination as well as for interviews.
(1)How does the switch decide which output port to place each packet on?
Answer: To make the decision the switch looks at the header of the packet for an identifier. Approaches which are being used
- Datagram or Connectionless approach.
- Connection-oriented or Virtual circuit approach.
- A third approach which is less common is source routing.
Each host has a unique address globally.There are some ways by which we can identify the input and output ports of each switch are using numbers or by using names.
(2) what are the characteristics of Datagram Network?
Answer: In datagram or connectionless network a host sends a packet anywhere with no time bound, since packets which are turns up at the switch can be instantly forwarded. When the host sends a packet, it does not knows if the network is capable of delivering it or if the destination host is even up and running packets are forwarded independently of previous packets that might have been sent to the same destination. A switch failure do not have any serious damage on communication if it is possible to find a substitute route around the failure and update the forwarding table as well .
(3)What is virtual circuit switching?
Answer: In and computer networks, a virtual circuit (VC), synonymous with virtual channel. This communication service is always connection oriented. It Is always delivered by packet mode communication. Virtual circuit switching is the widely used technique for packet switching. It uses the concept of virtual circuit (VC). It is also called a connection-oriented model. It always set up a virtual connection from the source host with the destination host and then send the data.
(4) Are network layer addresses physical or logical?
Answer: Network layer addresses are logical. It is specific to the network layer protocol & run on the network. Every network layer protocol contains a different addressing scheme. They are hierarchical. It usually define networks first and then the others like host or devices of that network. Example of a network address is the IP address.
(5) How do routers function at the network layer of the OSI model?
Answer: Routers have the work on different network is to learn, record, and maintain awareness. It decides the best way to these networks and record this information in a table called routing table.
The routing table includes the below mentioned:
- Network addresses, these are the protocol-specific. If we are running more than one protocol in one go, we have a network address for every and each protocol.
- The interface the router uses to route for a different network.
- A metric.
- Broadcast domains are made by routers.
(6) What is the responsibility of the data link layer (Layer 2)?
Answer: The data link layer gives functional and procedural means for connectionless mode among networks entities, and for connection mode entities it gives the establishment, maintenance, and also release of data link connections. The data link layer interprets messages from the network layer to the bits for the physical . It enables the network layer to control the interconnection of data circuits inside the physical layer. It defines different network and protocol characteristics.
(7) What are collision domains?
Answer: Devices connect to the same physical medium In Ethernet segments. Because of this, all signals are received by all devices sent across the wire. If two devices send a packet simultaneously, a collision occurs. In the matter of a collision, the two devices execute a back off algorithm and resend the packet. The devices retransmit up to 15 times. A jam signal is issues by the first station which detects the collision. When a jam signal is sent from a workstation, it alerts all of the machines on the segment, not only the two that collided; when the jam signal is on the wire, any workstations can not transmit data. If more collisions occur it slower down the network, because the devices will have to retransmit the packet.
(8) How do the different layers of the OSI model communicate with each other?
Answer: Every layer of the OSI model communicates only with its above layer, below layer, and layer parallel to it. For example, the presentation layer communicates with only the application layer, also with session layer, and presentation layer on the machine it is communicating with. These layers communicate with themselves by means of using protocol data units (PDUs). These PDUs control information that is added to the user data at each layer of the model. This information remains in fields called headers and trailers .
(9) What is data encapsulation?
Answer: A PDU includes different information as it goes up or down the OSI model. It is given a totally different name by means of its information which it is carrying. When the transport layer receives upper layer data, it adds a TCP header to the data; this is called a segment. The segment is then passed to the network layer, and an IP header is added; thus, the data becomes a packet. The packet becomes a frame after passing to the data link layer. This frame is then again converted to bits and is passed across the network medium.
(10) What are the functions of the session layer (Layer 5)? Give some examples.
Answer: The s layer 5 is responsible for initiating, controlling and ending communication sessions between presentation layer entities. These sessions includes service requests and responses that develop between applications located on different network devices. Some examples include SQL, RPC, NFS, X Window System, ZIP, Net Bios names, and Apple Talk ASP.
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