Open System Interconnect Model and Todays Networks - Research Paper Example

It is important to note that OSI modal is an abstract or conceptual model and often OSI model layers overlap functions and protocols in real networks. The first layer of OSI model is known as physical layer because it deals with physical media use to interconnect various machines in a network. This may include connectors, UTP and fiber optic cables or wireless access points, hubs, repeaters etc. Data at this layer is in the format of bits or electrical signals. The next comes the Data Link layer which is used to control the access to the communication channel described in the first layer.

This layers also set the pace of data flow over the data communication channel. Various devices used at this layer includes switches and bridges. Data at this layer is in the format of frames. The devices are identified based on their physical address at this layer and MAC address is used to address source and destination machines. High-level Data Link Control (HDLC), Frame Relay, PPP etc. are some the protocols used at Data Link layer. Network layer is basically used for logical addressing of source and destination machines.

IP Address are used this layer of the OSI Model. Router is the most important device used at this stage. It is an important layer where various protocols like IP, Internet Control Messaging Protocol (ICMP), Address Resolution Protocol (ARP), Reverse Address Resolution Protocol (RARP) etc are used. This layer ensures movement of data to corrected logical address of the machines. with accuracy and request retransmission if required. More importantly in today’s network for fast communications this layer ensures the selection of most optimal route through Open Shortest Path Fist (OSPF), Extended Gateway Protocol (EGP), Routing Information Protocol (RIP) and many other protocols.

Data is organized in packet at this layer. Transport layer transports and sequences packets in to data segments. It eliminates duplication and recovers data losses. It controls the overall flow of data and ensure accuracy and concurrency between communicating devices. TCP, UDP and NetBEUI are important protocols used at transport layer. Session layer opens, maintains, and closes session between applications. These sessions synchronize data communication between machines on a network. Various