The Osi And Open Systems Interconnection

956 WordsApr 3, 20174 Pages
The OSI, Open Systems Interconnection, model was first introduced in 1984 and was design to be a model and teaching tool to help better understand the rules of networking that systems must undergo to communicate. The OSI model consist of seven hierarchical layers that defines the path that data must travel. These layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The first and lowest level of the model is the Physical layer. The physical layer consists of the basic networking hardware transmission technologies of a network (Osi-model.com). Here you could find specifications for telecommunication like types of wired cables such as; copper, optical, or coaxial. In this layer, you would configure…show more content…
The third layer of the OSI model is the network layer and is where the routers and layer 3 switches would be. This layer is responsible for controlling subnets and deciding which path the data should take based on certain conditions. This layer is also responsible for IP (internet protocol) addresses, this includes both IPv4 and IPv6 addresses. Packets in this layer identify where the traffic originated (source IP address) and where it is going (destination IP address) (Gibson 166). In short, the OSI layer three network layer is responsible for connections, host addressing, and message forwarding. Protocols that operate on this layer are IPsec and ICMP. Layer four of the OSI model consist of the transport layer. In this layer, the protocols in this layer provide a host-to-host communication servers for applications (osi-model.com). Within the layer four transport layer, we have TCP (transmission control protocol) and UDP (user datagram protocol) protocols. TCP is a more reliable protocol in ways of guaranteeing the delivery of the IP traffic. With TCP, you have a three-way handshake in place, meaning that when you send a segment you should receive an acknowledgement that the segment was received. If it was not received, then you could resend. When using UDP, guarantee delivery of packets is not the main concern. The main advantage of UDP is that
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