What is networking

Networking is a common synonym for developing and maintaining contacts and personal connections with a variety of people who might be helpful to you and your career. It is an especially important aspect of career management in the financial services industry, since it is helps you keep abreast of:

• Career opportunities in your own firm
  
• Career opportunities in other firms
  
• Industry trends

Examples of OSI layer, their definition in order

1) Layer 7:Application Layer

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  Defines interface to user processes for communication and data transfer in network
  Provides standardized services such as virtual terminal, file and job transfer and operations

Layer 6:Presentation Layer

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  Masks the differences of data formats between dissimilar systems
  Specifies architecture-independent data transfer format
  Encodes and decodes data; Encrypts and decrypts data; Compresses and decompresses data

Layer 5:Session Layer

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  Manages user sessions and dialogues
  Controls establishment and termination of logic links between users
  Reports upper layer errors

Layer 4:Transport Layer

• Manages end-to-end message delivery in network
  Provides reliable and sequential packet delivery through error recovery and flow control mechanisms
  Provides connectionless oriented packet delivery

Layer 3:Network Layer

• Determines how data are transferred between network devices
  Routes packets according to unique network device addresses
  Provides flow and congestion control to prevent network resource depletion

Layer 2:Data Link Layer

• Defines procedures for operating the communication links
  Frames packets
  Detects and corrects packets transmit errors

Layer 1:Physical Layer

• Defines physical means of sending data over network devices
  Interfaces between network medium and devices
  Defines optical, electrical and mechanical characteristics

What is OSI layer

OSI (Open Systems Interconnection) is a standard description or "reference model" for how messages should be transmitted between any two points in a telecommunication network. Its purpose is to guide product implementors so that their products will consistently work with other products. The reference model defines seven layers of functions that take place at each end of a communication. Although OSI is not always strictly adhered to in terms of keeping related functions together in a well-defined layer, many if not most products involved in telecommunication make an attempt to describe themselves in relation to the OSI model. It is also valuable as a single reference view of communication that furnishes everyone a common ground for education and discussion

Examples of Network Topology, their definition, then post picture

Star TopologyMany home networks use the star topology. A star network features a central connection point called a "hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.
Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer's network access and not the entire LAN. (If the hub fails, however, the entire network also fails.)

Mesh TopologyMesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. (Recall that even in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs, most notably the Internet, employ mesh routing

Tree TopologyTree topologies integrate multiple star topologies together onto a bus. In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the "root" of a tree of devices. This bus/star hybrid approach supports future expandability of the network much better than a bus (limited in the number of devices due to the broadcast traffic it generates) or a star (limited by the number of hub connection points) alone.

Ring TopologyIn a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network.
To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring topologies are found in some office buildings or school campuses.

Bus TopologyBus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

What is networking topology

In computer networking, topology refers to the layout of connected devices. This article introduces the standard topologies of networking.
Topology in Network DesignThink of a topology as a network's virtual shape or structure. This shape does not necessarily correspond to the actual physical layout of the devices on the network. For example, the computers on a home LAN may be arranged in a circle in a family room, but it would be highly unlikely to find a ring topology there.