Skip to main content

Network Layer

Network Layer


[caption id="attachment_1462" align="alignnone" width="540"]Network Layer Network Layer[/caption]

Basic Requirement of Network Layer


The network layer is used to route data between different nodes on the network. It uses addresses to be able to tell which pc to send data to. This layer can also break apart larger messages into smaller chunks to be reassembled on the opposite end.



Network Layer Services



  1. Guaranteed delivery

  2. Guaranteed delivery with bounded delay

  3. In-order packet delivery

  4. Guaranteed minimal bandwidth

  5. Guaranteed maximum jitter

  6. Security services


1. Guaranteed Delivery


This service guarantees that the packet will eventually arrive at its destination.



2. Guaranteed Delivery with Bounded Delay


This service not only guarantees delivery of the packet, however delivery inside a mere host-to-host delay sure (for example, inside a hundred msec).


Furthermore, the following services could be provided to a How of products between a given source and destination.



3. ln-order Packet Delivery


This service guarantees that packets arrive at the destination in the order that they were sent.



4. Guaranteed Minimal Bandwidth


This network layer service emulates the behavior of a transmission link of a specified bit rate (for example, 1 Mbps) between sending and receiving hosts. As long because the causing host transmits bits (as a part of packets) at a rate below the required bit rate then no packet is lost and every packet arrives inside a prespecified host-to-host delay (for example, inside forty msec).



5. Guaranteed Maximum Jitter


This service guarantees that the quantity of your time between the transmission of 2 successive packets at the sender is equal to the quantity of your time between their receipt at the destination (or that this spacing changes by no over some mere value).



6. Security Services




Using a secret session key known only by a supply and destination host, the network layer within the supply host might encipher the payloads of all datagrams being sent to the destination host. The network layer within the destination host would then be answerable for decrypting the payloads. With such a service, confidentiality would be provided for all transport. layer segments (TCP and UDP) between the supply and destination hosts. additionally confidentiality, the network layer might give knowledge integrity and supply authentication services.




Read More

Popular posts from this blog

Limitations of Terzaghi Theory

Limitations of Terzaghi Theory The value of the coefficient of consolidation has been assumed to be constant.  The distance d of the drainage path cannot be measured accurately in the field. The thickness of the deposit is generally variable, and an average value has to be estimated.  There is sometimes difficulty 1n locating the drainage face, sometimes thin previous seams that can act as good drainage face are missed in the boring operations. The equation is based on the assumption that the consolidation is one-dimensional. In the field, the consolidation is generally 3-dimensional. The lateral drainage may have a significant effect on the time rate of consolidation. The initial consolidation and secondary consolidation have been neglected. Sometimes these form an important part of the total consolidation. In actual practice, the pressure distribution may be far from linear or uniform. Read More Muller-Breslau principle

Price Guard Wire Method

Price Guard Wire Method Some form of  Price Guard Wire Method  is generally used to eliminate the errors caused by leakage currents over insulation. Fig. 3.14 illustrates the operation of This Method. In fig 3.14(a), a high resistance mounted on a piece of insulating material is measured by the ammeter voltmeter method. The micro-ammeter measures the sum of the current through the resistor (IR) and the current through the leakage path around the resistor. The measured value of resistance computed from the readings indicated on the voltmeter and the microammeter, will not be a true value but will be in error.   Figure 3.14 Application of  guard  circuit for measurement of high resistance In fig, 3.14 (b), the  guard  terminal has been added to the resistance terminal block. The  guard  terminal surrounds the resistance terminal entirely and is connected to the battery side of the micro-ammeter. The leakage current IL now bypasses t

Negative Booster

Negative booster A negative booster is employed to conform to the regulation that the potential difference between any two points of the rail return shall not exceed 7 V. Two boosters, positive and negative, are used which are mechanically coupled together and driven by a DC motor. The positive booster is connected to the trolley wire (near the generating station) and the negative booster (separately excited) is connected to the track rail.  The 'positive booster' adds voltage to the line while the 'negative booster lowers the potential of the point it is connected to. As we go along the trolley wire away from the generating station/sub-station, the potential drop increases, and the voltage of the trolley wire falls. Since the current returns via the track rail points away from the generating station acquire high potentials. This potential is brought down by the negative boost provided by the negative booster. When the load is sufficiently far away from the generating stati