MARK JOHN



Friday, February 26, 2010

Wednesday, February 10, 2010

Example of networking devices and their functions, post at least 10 w/ picture.

Example of Networking, Post at least 5 examples with picture.

Example 1: Routed Ethernet w/ HomePNA Bridge
Routed Ethernet w/ HomePNA Bridge

Example 2: Ethernet & Bridged HomePNA w/ Multiple IPs from ISP
Ethernet & Bridged HomePNA w/ Multiple IPs from ISP



Example 3: DSL with Wireless Access Point (w/ NAT routing)
DSL Modem & Wireless Access Point example

Example 4: Ethernet, HomePNA, Wireless Combination
Ethernet, HomePNA, Wireless Combination

Example 5: Ethernet and Wireless Combination with Access Point
Mixed Wireless / Ethernet Network with Access Point.


What is Networking?

networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.

4. Examples of OSI Layer, their definition in order.

The specific description for each layer is as follows:
Layer 7:Application Layer
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
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
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
There are other network architecture models, such as IBM SNA (Systems Network Architecture) model . Those models will be discussed in separate documents.

3.What is OSI Layer?

The Open System Interconnection Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer network protocol design.

2.Examples of Network Topology, their Definition and post example picture.


Bus

Bus network topology

In local area networks where bus topology is used, each machine is connected to a single cable. Each computer or server is connected to the single bus cable through some kind of connector. A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable.
Star

Star network topology

In local area networks with a star topology, each network host is connected to a central hub. In contrast to the bus topology, the star topology connects each node to the hub with a point-to-point connection. All traffic that transverses the network passes through the central hub. The hub acts as a signal booster or repeater.

Ring

Ring network topology

In local area networks where the ring topology is used, each computer is connected to the network in a closed loop or ring. Each machine or computer has a unique address that is used for identification purposes. The signal passes through each machine or computer connected to the ring in one direction. Ring topologies typically utilize a token passing scheme, used to control access to the network.
Mesh

The value of fully meshed networks is proportional to the exponent of the number of subscribers, assuming that communicating groups of any two endpoints, up to and including all the endpoints, is approximated by Reed's Law.

Fully connected mesh topology

Fully connected




Tree

Tree network topology

Also known as a hierarchical network.

The type of network topology in which a central 'root' node (the top level of the hierarchy) is connected to one or more other nodes that are one level lower in the hierarchy (i.e., the second level) with a point-to-point link between each of the second level nodes and the top level central 'root' node, while each of the second level nodes that are connected to the top level central 'root' node will also have one or more other nodes that are one level lower in the hierarchy (i.e., the third level) connected to it, also with a point-to-point link,

WHAT IS TOPOLOGY?

topology is the modern version of geometry, the study of all different sorts of spaces. The thing that distinguishes different kinds of geometry from each other (including topology here as a kind of geometry) is in the kinds of transformations that are allowed before you really consider something changed