Networking - Circuit & Packet Switching, Frame Relay & ATM

• Point to point communication not usually practical 
• Devices are too far apart 
• Large set of devices would need impractical number of connections 
• Solution is a communications network

Simplified Network Model

Wide Area Networks

• Large geographical area 
• Crossing public rights of way 
• Rely in part on common carrier circuits 
• Alternative technologies 
• Circuit switching 
• Packet switching 
• Frame relay 
• Asynchronous Transfer Mode (ATM)

Circuit Switching

• Dedicated communications path established for the duration of the conversation 
• e.g. telephone network

Packet Switching

• Data sent out of sequence 
• Small chunks (packets) of data at a time 
• Packets passed from node to node between source and destination 
• Used for terminal to computer and computer to computer communications

Frame Relay

• Packet switching systems have large overheads to compensate for errors 
• Modern systems are more reliable 
• Errors can be caught in end system 
• Most overhead for error control is stripped out

Asynchronous Transfer Mode

• ATM 
• Evolution of frame relay 
• Little overhead for error control 
• Fixed packet (called cell) length 
• Anything from 10Mbps to Gbps 
• Constant data rate using packet switching technique

Networking - Circuit & Packet Switching, Frame Relay & ATM

Data and Computer Communication

A Communications Model

• Source 
• generates data to be transmitted 
• Transmitter 
• Converts data into transmittable signals 
• Transmission System 
• Carries data 
• Receiver 
• Converts received signal into data 
• Destination 
• Takes incoming data

Simplified Communications Model - Diagram

Key Communications Tasks

• Transmission System Utilization 
• Interfacing 
• Signal Generation 
• Synchronization 
• Exchange Management 
• Error detection and correction 
• Addressing and routing 
• Recovery 
• Message formatting 
• Security 
• Network Management

Simplified Data Communications Model

Data and Computer Communication

Hardest Thing to Break

WHAT is it that's hard to break???

Diamonds are hard to find but not hard to Break..

What is the hardest thing to break then?

The answer is: HABIT!

If you break the H, you still have A BIT. 

If you break the A, you still have BIT. 

If you break the B, you still have IT!

Hey, after you break the T in IT, there is still the 'I'.

And that (I) is the root cause of all the problems. 
 Now you know why HABIT is so hard to break….

Hardest Thing to Break

Very Weird Mouse for Laptop

Very Weird Mouse for Laptop

Hard Disk Clock

Hard Disk Clock

New Nokia C3, C6 and E5

 

  The first new product, Nokia C3, made in a candybar with a QWERTY-keyboard and is based on the platform S40. The phone has a 2.4-inch touchscreen display with QVGA, equipped with a 2-megapixel camera, a wireless interface module Wi-Fi and a slot for memory card formatMicroSD. In addition, the presence of support services Ovi Mail, Ovi Chat and networks GSM / EGSM (850/900/1800/1900 MHz). Presumably, the model will go on sale in the second quarter of this year and will be available in three colors: gray, pink and golden-white. The cost of the device - 90 euros. More images after the break...

 

Next novelty, Nokia C6, - is a smartphone, made in the slider and is equipped with QWERTY-keyboard. The device has a 3.2-inch 640x360 pixels, integrated GPS-navigator, 5-megapixel camera with autofocus and flash, 3.5-mm audio connector and a slot for memory card format MicroSD. Also "on board" device contains modules Bluetooth 2.0 and Wi-Fi, FM-tuner, 200 megabytes of internal memory and slot Micro-USB. Smartphone running the operating system Symbian S60 5.0. For sale Nokia C6 appears in the second quarter of this year with an estimated retail price of 220 euros. 

 

Following news of yesterday's events - Nokia E5. Like previous models, this has a built-in QWERTY-keyboard, and, except for "activists" of social networks, perfect for beznesmenov. Nokia E5 executed in a candybar, a 2.4-inch touchscreen display with QVGA resolution and runs under the operating system Symbian S60 3rd Edition. In the list of specifications of the device has built-in 5 megapixel camera with autofocus and LED-flash, Bluetooth 2.0 and Wi-Fi, jack 3,5 mm, GPS-receiver with A-GPS, 250 megabytes of internal memory, Micro-USB port and slot for memory card format MicroSD.  

 

 

New Nokia C3, C6 and E5

Some Tips and Tricks for WinXP

Opening Ports or Adding Allowed Programs with SP2's Firewall

1.Click on Start / Run
2.Enter in firewall.cpl
3.Click on the Exceptions tab


Adding a Port for Internet Access:
1.Click on the Add Port button
2.Name it whatever you want
3.Enter in the ports you want to open


Adding a Program for Internet Access
1.Click on Add Program... button
2.A list of all installed programs will be displayed
3.Highlight the one you want to include for Internet access
4.Click on the OK button


Autoexec.nt or Config.nt Errors

If you are getting errors similar to:
The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.
Try copying the file from \windows\repair directory to the one that is in the \windows\system32 directory.


Common Control Panel Applets

The follow are some common Control Panel Applets that are located in the \windows\system32 directory.
If you find yourself using any of these frequently, then you can simply make shortcuts to them on your desktop.


appwiz.cpl >>Add/Remove Programs
desk.cpl >> Display Properties
firewall.cpl >> Firewall Settings
inetcpl.cpl >> Internet Options
mmsys.cpl >> Sound and Audio
ncpa.cpl >> Network Connections
nusrmgr.cpl >> User Accounts
powercfg.cpl >> Power Options
sysdm.cpl >>System Properties
wscui.cpl >> Security Center
wuaucpl.cpl >> Automatic Updates Configuration



Windows Explorer Opens Search Companion Rather than the Folder
If the Windows Explorer opens up the Search Companion rather than opening up the actual folder, the default setting for opening a folder is changed.


To correct this:
Start Regedit
Go to HKEY_CLASSES_ ROOT \ Directory \ shell
Edit the default value to be explorer or none



Guest Only Network Access

If you try and connect to an XP computer and are shown a logins screen with only the computername/ Guest,
You may need to change one of the Local Security Policies:
Got to Control Panel - Administrative Tools
Go to Local Policies - Security Options
Check teh Network access: Sharing and security model for local accounts
Set it to Classic - local users authenticate as themselves



Hiding a XP Computer from Network Neighborhood

If you want to share files from a XP computer,
yet want to remove it from showing up in the Network Neighborhood,
Run net config server /hidden:yes



Easy Way to Share Multiple Folders

If you need to share multiple folders, running the program SHRPUBW.EXE will bring up a simple dialog box to let you:
Browse to the folder you want to share
Enter in a Share name
Ender in a Share description
Set permissions. Several choices are available
Restart the process from within the same program



Setting Capslock, Numlock, Scroll Lock

If you want to set the startup state for any or all of these keys,
you just need to edit the registry.
Start Regedit
Go to HKEY_CURRENT_ USER \ Control Panel \ Keyboard
Open InitialKeyboardIndi cators
Change the value to one of the following numbers
0 - All Keys off
1 - Caps Lock on
2 - Num Lock on
4 - Scroll Lock on
For multiple keys, add their values:
3 - Caps Lock and Num Lock on
5 - Caps Lock and Scroll Lock on
6 - Num Lock and Scroll Lock on
7 - Caps Lock, Num Lock, and Scroll Lock on
Log off and back on again


Restoring Desktop Icon to the Quicklaunch Bar

If you mistakenly deleted the icon for the Desktop on the Quicklaunch toolbar
Go to C:\Documents and Settings\user_ name\Application Data\Microsoft\ Internet Explorer\Quick Launch
(where user_name is replaced by your login name)
Create a Text file called ShowDesktop. SCF with the following contents:
[Shell]
Command=2
IconFile=explorer. exe,3
[Taskbar]
Command=ToggleDeskt op


Network Access After Norton Anti-Virus Install

Sometimes you can't access a WinXP computer after installing Norton Anti-Virus.
There might be a variety of errors at the other computer depending on the operating system.
On the XP computer, in the Event Viewer / System log, there will be the following error:
The servers configuration parameter "irpstacksize" is too small for the server to use a local device.
Start Regedit
Go to HKEY_LOCAL_MACHINE\ SYSTEM\CurrentCo ntrolSet\ Servic es\lanmanserver\ parameters
Edit the IRPStackSize
Give it a value of 15
Reboot the computer


Configure for Auto-Logon

If you are the only person using the computer and what to have it automatically log you on,
Start / Run / "control userpasswords2" - no quotes
Uncheck User must enter a user name and password to use this computer
Services You Can Disable
There are quite a few services you can disable from starting automatically.
This would be to speed up your boot time and free resources.
They are only suggestions so I suggestion you read the description of each one when you run Services
and that you turn them off one at a time.

Some possibilities are:
Alerter - Sends alert messages to specified users that are connected to the server computer.
Application Management - Allows software to tap directly into the Add/Remove Programs feature via the Windows Installer technology.
Background Intelligent Transfer Service - The Background Intelligent Transfer service is used by programs (such as Windows AutoUpdate) to download files by using spare bandwidth.
Clipbook - ClipBook permits you to cut and paste text and graphics over the network.
Error Reporting Service - Allows applications to send error reports to Microsoft in the event of an application fault.
Fast User Switching - Windows XP allows users to switch quickly between accounts, without requiring them to log off.
Help and Support - Allows the XP Built-in Help and Support Center to run.
IMAPI CD-Burning COM Service - You don't need this if you have other software to create CDs.
Indexing Service - Indexes contents and properties of files on local and remote computers; provides rapid access to files through flexible querying language.
IP SEC - Manages IP security policy and starts the ISAKMP/Oakley (IKE) and the IP security driver. If you are not on a domain, you likely don't need this running.
Messenger - Transmits net send and Alerter service messages between clients and servers. This is how a lot of pop-up windows start appearing on your desktop.
Net Logon - Supports pass-through authentication of account logon events for computers in a domain. If you are not on a domain, you don't need this running
Network DDE - Provides network transport and security for Dynamic Data Exchange(DDE) for programs running on the same computer or on different computers.
NT LM Security Support Provider - Provides security to remote procedure call (RPC) programs that use transports other than named pipes.
Performance Logs and Alerts - Collects performance data from local or remote computers based on preconfigured schedule parameters, then writes the data to a log or triggers an alert. If you don't need to monitor your performance logs, then you don't need this service.
Portable Media Serial Number - Retrieves the serial number of any portable music player connected to your computer
QOS RSVP - Provides network signaling and local traffic control setup functionality for QoS-aware programs and control applets.
Remote Desktop Help Session Manager - Manages and controls Remote Assistance. If you are not using Remote Desktop you don't need this service.
Remote Registry - Enables remote users to modify registry settings on this computer.
Routing & Remote Access - Offers routing services to businesses in local area and wide area network environments. Allows dial-in access.
Secondary Login - Enables starting processes under alternate credentials. This is what allows you to run an application as another user.
Smart Card - Manages access to smart cards read by this computer.
Smart Card Helper - Enables support for legacy non-plug and play smart-card readers used by this computer.
SSDP Discovery Service - Enables discovery of UPnP devices on your home network.
TCP/IP NetBIOS Helper - Enables support for NetBIOS over TCP/IP (NetBT) service and NetBIOS name resolution. This should not be needed in today's network environment.
Telnet - Enables a remote user to log on to this computer and run programs, and supports various TCP/IP Telnet clients.
Uninterruptible Power Supply Service - Manages an uninterruptible power supply (UPS) connected to the computer.
Universal Plug and Play Device Host - Provides support to host Universal Plug and Play devices
Upload Manager - Manages synchronous and asynchronous file transfers between clients and servers on the network.
Volume Shadow Copy Service - Manages and implements Volume Shadow Copies used for backup and other purposes.
Web Client - Enables Windows-based programs to create, access, and modify non-local files across the Internet.
Wireless Zero Configuration - Provides automatic configuration for the 802.11 adapters
WMI Performance Adapter - Provides performance library information from WMI HiPerf providers.
These are some tips to use winxp as per your requirement. please restore your system before made any chhanges un registery

Some Tips and Tricks for WinXP