07-04-2012, 03:48 PM
Basic Networking
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INTERNETWORK
An internetwork is a collection of Individual networks connected by Intermediate networking devices that Function as a single large network. Networks and networking have grown exponentially over the last 15 years—understandably so. They’ve had to evolve at light speed just to keep up with huge increases in basic mission critical user needs such as sharing data and printers as well as more advanced demands such as Video conferencing. Unless everyone who needs to share network resources is located in the same office area (an increasingly uncommon situation), the challenge is to connect the sometimes many relevant networks together so all users can share the networks’ wealth.
TOPOLOGY
Network topology refers to the arrangement of physical layout of computer, cables and other components on the network. Various kind of topologies are:
Single Node Topology
Single device, at times device called dumb terminal is connected to the server.
Device operates on files from server and returns them back after completing task.
RING Topology
Devices are connected in a closed loop.
All devices have equal access to media.
Device waits for its turn to transmit.
The signal travels around the loop in one direction and pass through each computer.
Computer acts like a repeater to boost the signal and sends it on the next computer.
TYPES OF NETWORK
1.4.1 Local Area Network (LAN)
A LAN is any type of network used within a single facility such as a campus to share data between computers. The computers or clients are physical connected and they can share data
Metropolitan Area Network (MAN)
MAN is one of the types of networks in which two or more LANs are connected. MAN is used where a company is connected with many LANs that cover a large area or more than one campus. It is used in shorter range connectivity solutions within the same city
Wide Area Network (WAN)
Wide are network spreads over very large geographical area. Most companies have both LANs and WANs. The main purpose of WAN is to provide reliable, fast, and safe communication between two or more places.
Virtual Private Network (VPN)
Virtual Private Network is a network that uses a public telecommunication infrastructure, like the Internet to provide remote offices or individual users with secure access to their organization’s network.
The Presentation Layer
The Presentation layer gets its name from its purpose: It presents data to the Application layer and is responsible for data translation and code formatting. This layer is essentially a translator and provides coding and conversion functions. A successful data-transfer technique is to adapt the data into a standard format before transmission.
The Session Layer
The Session layer is responsible for setting up, managing, and then tearing down sessions between Presentation layer entities. This layer also provides dialog control between devices, or nodes. It coordinates communication between systems and serves to organize their communication by offering three different modes: simplex, half duplex, and full duplex. To sum up, the Session layer basically keeps different applications’ data separate from other applications’ data.
The Transport Layer
The Transport layer segments and reassembles data into a data stream. Services located in the Transport layer segment and reassemble data from upper-layer applications and unite it into the same data stream. They provide end-to-end data transport services and can establish a logical connection between the sending host and destination host on an internetwork. Some of you are probably familiar with TCP and UDP already.
New DNS Features
The DNS Server role in Windows Server 2008 contains four new or enhanced features that improve the performance of the DNS Server service or give it new abilities:
• Background zone loading: DNS servers that host large DNS zones that are stored in Active Directory Domain Services (AD DS) are able to respond to client queries more quickly when they restart because zone data is now loaded in the background.
• IP version 6 (IPv6) support: The DNS Server service now fully supports the longer addresses of the IPv6 specification.