The network layer design issues contain the services position to the transport layer, routing packets over the subnet, congestion control, and connection of multiple networks together.
The design issues of the network layer are as follows −
It is the network layer's goals to support logical services to several users linked to multiple networks. Hence, the services supported should be autonomous of the basic technology. In this way, the client's use of the service requires inconvenience with the network's physical execution to send their messages.
The transport layer at the host device should not require knowing how the broadcasting connection with the destination device is set up.
It must be some uniform addressing design for network location.
There are two types of communications as follows −
In a connection-oriented service, each packet is related to a source/destination link. These packets are routed along a similar path called a virtual circuit. Therefore, it supports an end-to-end connection to the customer for stable data transfer. It transfers data in order without parallel or missing information. It does not congest the transmission medium and the buffer of the receiving device.
In the connection-oriented service, the user connects the network's bandwidth and resources for the connection span and hence is destined to allowance more. This service also maintains network resources associated even when there is no transmission during the link.
In connectionless service, a router considers each packet separately. The packets are routed through several paths through the web as per the decision created by routers.
The web or communication channel does not guarantee data delivery from the host machine to the destination machine in connectionless service. The record to be transmitted is fragmented into packets. These separate packets are known as datagrams in similarity with telegrams. The packet contains the address of the destination device.
Each service can be distinguished by its quality of service.
These services can be of two types as explained below −
Reliable services are those which never lose data. It is usually a reliable service implemented by having the receiver acknowledgements of receipt of each message. Therefore, the sender is sure that it arrives. For example, remote login requires reliable service. But the declarations introduce overheads and delays, which are sometimes undesirable.
Unreliable services lose minimal data or bits or pixels of the picture, but there is no significant effect on the result. For example, mobile customers should hear a bit of noise on the line or a misinterpret term from time to time than to learn a delay to wait for acceptance.