CCNA Network Models

CCNA Network Models

To simplify networks, everything is separated in layers and each layer handles specific tasks and is independent of all other layers. Control is passed from one layer to the next, starting at the top layer in one station, and proceeding to the bottom layer, over the channel to the next station and back up the hierarchy. Network models are used to define a set of network layers and how they interact. The two most widely recognized network models include the TCP/IP Model and the OSI Network Model in CCNA Training In Chandigarh.

7 Layers of the CCNA OSI Network Model

The Open System Interconnect (OSI) is an open standard for all communication systems.The OSI model defines a networking framework to implement protocols in seven layers.

This layer conveys the bit stream — electrical impulse, light or radio signal — through the network at the electrical and mechanical level. It bring the equipment methods for sending and accepting information on a transporter, alongside characterizing links, cards and physical appearance. Illustrations incorporate Ethernet, FDDI, B8ZS, V.35, V.24, RJ45.

At this layer, data packets are encoded and decoded into bits. It furnishes transmission protocol knowledge and management and handles errors in the physical layer, flow control and frame synchronization. The data link layer is prorated into two sublayers: The Media Access Control layer and the Logical Link Control layer. Examples include PPP, FDDI, ATM, IEEE 802.5/ 802.2, IEEE 802.3/802.2, HDLC, Frame Relay.

This layer give straightforward exchange of information between end frameworks, has, and is at fault for end-to-end blunder resumption and stream control. It guarantees finish information transfer.Examples incorporate SPX, TCP, UDP.

This layer sets up, oversees and ends associations between applications. The session layer sets up, facilitates, and ends discussions, trades, and discoursed between the applications at each end.

This layer gives freedom from contrasts in information portrayal (e.g., encryption) by making an interpretation of from application to organize organization, and the other way around. This layer adjustment and encipher data to be sent across a network, given privilege from affinity problems. Examples include encryption, ASCII, EBCDIC, TIFF, GIF, PICT, JPEG, MPEG, MIDI.

This layer supports application and end-user processes. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified. Everything at this layer is application-specific. This layer produce application services for file transmission, e-mail, and other network software services. Examples receive WWW browsers, NFS, SNMP, Telnet, HTTP, FTP

The TCP/IP network model is a four-layer reference model. All protocols that belong to the TCP/IP protocol suite are located in the top three layers of this model.

Defines TCP/IP application protocols and how anchor programs assemblage with transport layer services to use the network. Protocol examples comprise HTTP, Telnet, FTP, TFTP, SNMP, DNS, SMTP.

Provides communication session management between host computers. Defines the level of service and status of the connection used when transporting data. Protocol examples include TCP, UDP, RTP.

Packages data into IP datagrams, which consist of source and terminal address instruction that is used to forward the datagrams between hosts and beyond networks. Performs routing of IP datagrams. Protocol examples include IP, ICMP, ARP, RARP.

Specifies details of how data is physically sent through the network, including how bits are electrically signaled by hardware devices that interface directly with a network medium, such as coaxial cable, optical fiber, or twisted-pair copper wire. Protocol examples include Ethernet, Token Ring, FDDI, X.25, Frame Relay, RS-232, v.35.

Each layer of the TCP/IP model corresponds to one or more layers of the seven-layer Open Systems Interconnection (OSI) reference model.

Network topology refers to the shape or the arrangement of the different elements in a computer network (i.e. links and nodes). Network Topology defines how different nodes in a network are connected to each other and how they communicate is determined by the network’s topology.

Topologies are either physical or logical. There are four important topologies utilized as a part of LANs.

All equipment are connected to a central cable, called the bus or backbone. Bus networks are relatively inexpensive and easy to install for small networks.

All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it.

All devices are connected to a central hub. Star networks are essentially easy to install and protect, but impediment can occur because all data must passage through the nerve center.

A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable.

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