Depending upon your requirement , you can choose either PRTG Network Monitor or Traffic Grapher

Comparison between PRTG Network Monitor 7 PRTG Traffic Grapher 6

PRTG Network Monitor :

It monitors your network using a whole range of technologies and assures the availability of network components and measures traffic and usage. It saves costs by avoiding outages, optimizing connections, saving time and controlling service level agreements (SLAs).

For more details: http://www.paessler.com/prtg7/

PRTG Traffic Grapher:

PRTG (Paessler Router Traffic Grapher) is an easy to use software that monitors bandwidth usage and many other network parameters via SNMP, Packet Sniffing, or Cisco NetFlow. It allows you to quickly and easily set up and run a monitoring station for networks. With just a few mouse clicks you can log the amount of data flowing through routers and leased lines, monitor CPU utilization, analyze the traffic by type, or check disk space usage.
The most common usage is monitoring the bandwidth usage of leased lines, routers, and firewalls via SNMP, packet sniffing, or NetFlow. But you can also monitor many other aspects of servers, managed switches, printers, and other network components, as long as they are SNMP enabled.
For more details: http://www.paessler.com/prtg6

Installing PRTG

PRTG Network Monitor is optimized for easy installation, configuration and use. It allows you to set up your complete network monitoring scenario within minutes.Simply download the file and double-click it to start installation. The process is simple and consists entirely of answering routine questions, such as the installation path.
What is SNMP?

It stands for Simple Network Management Protocol, and is a set of standards for communication with devices in a TCP/IP network. With the help of an SNMP tool, it is possible to monitor and control network devices such as hosts, routers and switches.

A videoconferencing facility consists of many elements.All conferencing systems use CODEC, which stands for coder-decoder. Codec is a device, which converts and compresses an analog audio-video signal into digital data and then sends it over a digital line. The decoder reverses the process at the receiving end.

This compression and decompression allows large amounts of data to be transferred across a network at close to real time (384 kbps with 30 frames of video per second).  All video conferencing systems works in a full duplex mode i.e. encoding and decoding of audio-video in both directions simultaneously.

One can use a choice of networks for conducting video conferencing over wide area networks (WAN) such as ISDN lines or satellite based lease lines. It is perfectly possible to use bandwidth of 128 KBPS for good quality conference. However data rate of 384 kbps may be needed for near TV quality video.

Various components of VC Equipment:

Following are the basic components of a videoconferencing system
• Codec
• Camera
• Control system
• Display equipment
• Audio system

Multipoint Videoconferencing:

Multipoint videoconferencing allows three or more participants to sit in a virtual conference room and communicate as if they were sitting right next to each other. Multipoint Videoconferencing is possible using Multipoint Conference Server.. MCS is the central point of connectivity for endpoints. It enables different networks, different bandwidths and different types of endpoints to communicate effectively.
Multipoint Conference Server acts as a switching device, connecting multiple sites at the same time to become part of same conference. It also provides facility to run multiple conferences with varying data rates, to operate in parallel over one network. The digital video signals from various Codecs are fed to the MCS, which is controlled through a workstation, (commonly a PC) to monitor and control various conferences. Accounting and scheduling related jobs are done through the workstation. For more details , visit www.polycom.com

Advantages of Video Conferencing:
Video conferencing is used by many businesses usually to save both time and money. One of the great advantages of video conferencing is that two or more parties can have a virtual face to face meeting to conduct business, which is seen as more beneficial than just a conference call. Other parties such as educators and health professionals use video conferencing when giving lectures, teaching about topics that require visual cues or visual information. Health professionals can give a diagnosis by conducting an examination via a video conference. There are many advantages to this technology and this has a lot to do with its exponential growth in recent years.

If you are looking for videoconferencing equipments/products ,
visit www.polycom.com or www.tandberg.com

You need a cable to connect the PC to the modem. The cable is the same as is used for
normal EIA-232 remote control, and comprises 3-wires between 9 pin ‘D’ type female connectors.

 Serial Cable Detail for Modems:

  DB9  Female at both ends of the cable

  Pin 2  ——-  Pin 2
  Pin 3  ——-  Pin 3
  Pin 5  ——-  Pin 5

  NO OTHER PINS SHOULD BE CONNECTED
1.First,Using the front panel,Check the firmware information on your Modem. The firmware information is usually found in the Main menu. Identify the reflashable product, firmware number, and version to download.

2. The files are available in two formats: *.exe (self extracting) and *.zip (compressed).  For additional help with “zipped” file types, refer to “pkzip” or “winzip”.

3.Download the correct firmware and Extract the same on your PC.

4. Extract the files on your PC.

A minimum of 3 files are extracted:

*.exe – the “uploader” executable program to apply the flash firmware data file

*.hlp – the “help” file used by the “uploader” program

*.ccc, *.cef or *.h86 – the flash firmware data file specific to the product you selected

5. Connect the PC to the device to be reflashed.

Connect the PC to the device to be reflashed using a 9-pin serial cable or USB cable. Consult the product manual to determine which connection type is appropriate.

6. To reflash the device:

From the PC, run the exe program that was extracted in step 4.

Follow the on-screen directions to apply the correct data file (*.ccc) and perform the actual reflash process.

For more information about flash updates, refer to the applicable product manual or Visit Comtech WEbsite for more details!

For Comtech CDM 600 series Modem, Refer the following details!

Product                    Loader to use    File ext

CDM-600 Modem         Flash600            CCC

Step by step Procedure !

1. Click the Loader file (the exe file Flash600.exe).
   Select your Com Port
   The baud rate is dictated by the type of Upload being done.

2. Click the Software Upload Button ,you will get a Window like the one below!

3.Click the Choose Button,you will get a window as below.

 4.Now, Choose the latest firmware file . The extention of the file is *.ccc for CDM 600 Modems. Choose the correct file and click ok.

5. Now before proceeding further, make sure your Modem is off and no cable is connected to the 25-Pin Data connector(P3B).   Turn off your modem if its on. than click start Upload.

6.Now,Switch on the Modem.

————————————–

7.Now,The modem will start upgrading the Firmware.

8.When its done,It will rebbot and query the modem for memory checksums.

Once its finished, Your modem is with the latest firmware. Now,cycle power the modem and check the main menu for the Firmware version.

The primary function of this layer is to control the communications session between network nodes once a path has been established by the network control layer.

Responsible for the following :
•Segmentation
•End-to-end Communication
•Flow Control
•Error Control
•Multiplexing of Applications

TCP, UDP work at this layer.

• It uniquely identifies each device in the Network.
• It translates data from Network Layer into bits for the Physical
  layer to transmit.
• It formats the messages into Data Frames
• Adds a customized header containing Source and Destination
  hardware address

Devices that works at this layer are
-LAN Card
-Switches
-Bridges etc.

In other word, it is responsible for establishing paths for data transfer through the network.

• The Network Layer resides above the Data Link Layer and below the Transport Layer.
• It is responsible for communicating Networks.
• The Network Layer is also responsible for packet sequencing, congestion control, and error handling.
• It recognizes Networks with the help of Network Addresses
• Network Address is a logical address like IP Address or IPX Address
• Path determination or Routing is performed at this layer.
• Router works at this layer.

The Transport Layer is also responsible for fragmentation and reassembly.The primary function of this layer is to control the communications session between network nodes once a path has been established by the network control layer.

Responsible for the following :
• Segmentation
• End-to-end Communication
• Flow Control
• Error Control
• Multiplexing of Applications

TCP, UDP work at this layer.

In other word, It is a set of rules for establishing and terminating data streams between nodes in a network. The services that this layer can provide include establishing and terminating node connections,
message flow control, dialogue control and end-to-end data control.

• The Session layer is responsible for setting up, managing, and then tearing down sessions between Presentation layer entities.
• It coordinates communication between systems, and serves to organize their communication by offering three different modes: simplex, half duplex, and full duplex.
• The Session layer basically keeps different applications’ data separate from other applications’ data.
• Examples of Session Layer : RPC, SQL, NFS and NetBIOS .

Points to Remember:

• Tasks like Translation, Encryption, decryption, compression,decompression are associated with this layer.
• Protocols at this layer take care of manipulation tasks that transform data from one representation to another, such as translation, compression and encryption.
• It is used much less often than the other layers , in many types of connections it is not required.
• It receives the data in native format & converts in standard format or receives data in standard format and converts in native format.
• It is mainly responsible for how the data is to be presented to the Application Layer.
• Examples are  MIDI, MPEG, GIFF , PICT, TIFF, JPEGetc.

About Application Layer

• This is a point where user or application interfaces with the protocols to gain access to the network.
• This is the top layer of the OSI model.
• This is where communication between two users are established.
• This is where users communicate to the computer.
• The application layer is only concerned with presenting information in human-friendly way.
• The Application Layer receives its information from the ‘Presentation’ layer.
• Examples are WWW, Telnet, FTP, TFTP, E-mail, SNMP,POP3, DNS