Network Layer Flashcards
Which Layer of the OSI model is the Network Layer?
3rd Layer
Which layer of a network is the Network Layer?
Lowest layer that deals with end-to-end transmission
What are the functions of the Network Layer?
- Routing
- Local Addressing
What does Local Addressing involve?
In order to identify each device on internetwork uniquely, network layer defines an addressing scheme. The sender & receiver’s IP address are placed in the header by network layer. Such an address distinguishes each device uniquely and universally.
https://www.geeksforgeeks.org/layers-of-osi-model/
What is a Routing Algorithm?
- Determines how to choose which path to use
- Chooses the transmission line!!
- the part of the network layer software responsible for deciding which output line an incoming packet should be transmitted on.
BONUS: What are the layers of the OSI model? (in order)
- Physical Layer (Lowest layer)
- Data Link Layer (DLL)
- Network Layer
- Transport Layer
- Session Layer
- Presentation Layer
- Application Layer
What are the Network layer design issues?
- Store-and-Forward Packet Switching
- Services Provided to the Transport Layer
- Implementation of Connectionless Service
- Implementation of Connection-Oriented Service
What is the Store-and-Forward Packet Switching design issue?
it is where the foremost elements are the carrier’s equipment (the connection between routers through transmission lines) and the customer’s equipment.
This switching network performs as Transmission of data happens when the host (H1) with a packet transfers it to the nearby router through LAN (or) point-to-point connection to the carrier. The carrier stores the packet until it completely arrives thus confirms the checksum.
Then after, the packet is transmitted over the path until H2 is reached.
H1 has a direct connection with carrier router ‘A’, while H2 is connected to carrier router ‘F’ on a LAN connection.
What is the Services Provided to the Transport Layer design issue?
What type of services does the network layer provide to the Transport Layer?
Through the network/transport layer interface, the network layer delivers its services to the transport layer.
Services offered by the network layer are outlined considering few objectives. Those are:
- Services independent of router tech
- Transport layer sheilded from number, type and topology of routers
- network addresses made available to transp layer use a uniform numbering plan, even in LANs and WANs
What are the 2 groups on the services offered by the network layer?
Connectionless – Here, routing and insertion of packets into subnet is accomplished individually. No additional setup is necessary
Connection-Oriented – Subnet must offer reliable service and all the packets are transmitted over a single route.
How is the implementation of Connectionless Service?
packets are termed as datagrams and the corresponding subnet is termed as datagram subnet. Routing in datagram subnet is as follows:
When the message size that has to be transmitted is 4 times the size of the packet, then the network layer divides into 4 packets and then transmits each packet to router ‘A’ through a few protocols. Each router is provided with a routing table where it decides the destination points.
How is the implementation of Connection-Oriented Service?
the functionality of connection-oriented service works on the virtual subnet. A virtual subnet performs the operation of avoiding a new path for each packet transmission. As a substitute for this, when there forms a connection, a route from a source node to a destination node is selected and maintained in tables. This route performs its action at the time of traffic congestion.
At the time when the connection is released, the virtual subnet also gets dismissed. In this service, every packet carries its own identifier that states the exact address of the virtual circuit.
