OSI (Open Systems Interconnection)
OSI is a conceptual model consisting of seven layers, each layer has a different function. OSI was developed by the international agency that is ISO (International Organization for Standardization) in 1977.
The function of each layer of the OSI:
1. Physical Layer
Physical Layer is the layer that very simple, relating to electrical (and optical) connections between devices. This layer Serves to define the network transmission media, signaling method, synchronization bits, network architecture (such as Ethernet or Token Ring), network topology and pengabelan. In addition, this level also defines how the Network Interface Card (NIC) can interact with the media cable or radio.
2. Data-link Layer
Data link layer is responsible at the end of the package binary data derived from a higher level into discrete packets before the physical layer. Will send frames (block of data) via a network. Protocol on the data-link layer is Ethernet (802.2 & 802.3), Tokenbus (802.4) and Tokenring (802.5).
3. Network Layer
Network layer provides routing functionality so that packets can be sent out from the local network segment to a destination that is on a network other.
Some network layer functions:
- Divide the binary data stream into discrete packets with a certain length
- Detect Error
- Fix error with resend the corrupted packet
- Controlling the flow
4. Transport Layer
Transport layer is the center of the fashion-OSI. Serves to break down data into packets of data and provide the serial number of the packages that can be rearranged on the side of the goal as it arrives.
5. Session Layer
This layer coordinates communication between the layer entities they represent. Serves to define how the connection can be established, maintained, or destroyed. In addition, at this level also performed name resolution. Some of the protocol at this layer: NETBIOS: a session interfaces and protocols, developed by IBM, which provides service to the presentation layer and application layer. NETBEUI, (NETBIOS Extended User Interface), a development of NETBIOS used in micro ** oft networking products, such as Windows NT and LAN Manager. ADSP (AppleTalk Data Stream Protocol). PAP (Printer Access Protocol), which is found on a Postscript printer to access the AppleTalk network.