Saranya M

Know The Difference Between Hubs, Switches and Routers...

Some technicians have a tendency to use the terms routers, hubs and switches interchangeably. One minute they're talking about a switch. Two minutes later they're discussing router settings. Throughout all of this, though, they're still looking at only the one box. Ever wonder what the difference is among these boxes? The functions of the three devices are all quite different from one another, even if at times they are all integrated into a single device. Which one do you use when? Let's take a look...

Hub, Switch, and Router Defined
Hub
A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Switch
In networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.

Router
A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP.s network. Routers are located at gateways, the places where two or more networks connect. Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.

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TECH WATCH...

Network Types

Main Network Types

• Ethernet
• FDDI
• Token Ring
• ARCnet
• AppleTalk

Other Network Types

• Fiber channel - Operates at 256 Mbps or 1 Gbps. It was developed for peripheral devices like disk arrays, but is now used for point to point networking for full duples server to server communications. It is the lowest cost 1 Gbps network.
• Gigabit Ethernet - This type of ethernet places ethernet packets in fiber channel packets. The fiber channel network works like an ethernet bridge.

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MAC OS X Snow Leopard...what's new-check out!!!!

Refined, not reinvented.

Mac OS X is renowned for its simplicity, its reliability, and its ease of use. So when it came to designing Snow Leopard, Apple engineers had a single goal: to make a great thing even better. They searched for areas to refine, further simplify, and speed up — from little things like ejecting external drives to big things like installing the OS. In many cases, they elevated great to amazing. Here are just a few examples of how your Mac experience was fine-tuned.

A more advanced, more nimble Finder.

The Finder has been completely rewritten in Cocoa to take advantage of all the modern technologies in Mac OS X, including 64-bit support and Grand Central Dispatch. It’s more responsive from top to bottom, with snappier performance throughout the Finder. And it includes new features such as customizable Spotlight search options and an enhanced icon view that lets you thumb through a multipage document or watch a QuickTime movie.

Quicker Time Machine backup.

Introduced in Mac OS X Leopard, the revolutionary Time Machine made backing up your hard drive easy for the first time. Time Capsule took backup even further with its wireless hard drive that works seamlessly with Time Machine. Now Snow Leopard makes Time Machine up to 80 percent faster and reduces the time it takes to complete your initial backup to Time Capsule.

Faster to wake up and shut down.

With Snow Leopard, your Mac wakes from sleep up to twice as quickly when you have screen locking enabled. And shutting down is up to 80 percent faster, saving precious moments when you’re trying to head home or to the airport.

Faster, more reliable installation.

Upgrading your Mac has never been easier. For Snow Leopard, the entire process has been simplified, streamlined, and is up to 50 percent faster, yet more comprehensive and reliable.² For example, Snow Leopard checks your applications to make sure they’re compatible and sets aside any programs known to be incompatible. In case a power outage interrupts your installation, it can start again without losing any data.

Smaller Foot Print:

Snow Leopard takes up less than half the disk space of the previous version, freeing about 7GB for you — enough for about 1,750 more songs³ or a few thousand more photos.

Another leap forward for QuickTime.

QuickTime X is the next-generation media technology that powers the audio and video experience in Mac OS X Snow Leopard. It includes a completely new QuickTime Player application with a clean, uncluttered design, a new trimming interface, and easy uploads to YouTube and MobileMe. And it delivers more efficient media playback, HTTP-based live streaming, and greater color accuracy.

Innovative Chinese character input.

Until Snow Leopard, if you wanted to enter Chinese characters on a computer, you had to type in the phonetic spelling of Chinese words and the computer would convert them into proper Chinese characters. Snow Leopard offers a breakthrough new way to enter characters: You write them directly on the Multi-Touch trackpad in your Mac notebook. They’ll appear on the screen in a new input window, which recommends characters based on what you drew and lets you choose the right one. The input window even offers suggestions for subsequent characters based on what you chose.

More reliable, higher-resolution iChat.

Having a video chat using iChat is more reliable and more accessible than ever in Snow Leopard.⁴ It includes technology to address many common router incompatibilities that can interfere with connections. And if iChat can’t make a direct connection, it will use the AIM relay server to create a successful chat session.

Now more people can have high-resolution, 640-by-480-pixel video chats, because the technical requirements are less demanding: You need only one-third the upstream bandwidth previously required — 300 Kbps instead of 900 Kbps. And finally, iChat Theater now offers 640-by-480 resolution, four times greater than before.