Video Chat: Many Uses for Business and Enjoyment

Whatรขโ�ฌโ�ขs new in video chat? Although the technology for using a web cam to send live pictures and video over the internet has been around for a long time, video chat technology continues to get better and better. Since the tragedy of 9-11, when businesses started traveling less, it became a great way for businesses to communicate with distant clients, other branches, and other businesses. Video chat can also bring individuals and families who are far apart closer together through the "magic" of the internet.

When businesses use video chat to conference rather than using a simple conference call on the telephone, they can not only see reactions of the people that they are talking to, but they can have a more "natural" conversation with everyone in the room. It helps to bring more confidence to all of the parties involved.

As far as recreational or social uses, video chat has many applications there as well. Xbox allows people who are connected through its gaming website to have live video feeds from both players. Many singles or dating sites allow their users to connect via a video chat so that they can get a clear picture of who they are chatting with. Yahoo Messenger has a premium service (for a fee) where users can interact with other chat room guests by video.

Of course in order to use all of these features you will need to have the correct software, equipment, and internet connection. Both users should have the same video software, or at least compatible chat software. If you are on a chat room site they will provide you with a software download. Then, you will need a camera. You can get an inexpensive web cam, but the pictures may be grainy and unclear, or you can get a video camera with USB 2.0 or Firewire installed. Your computer should be at least a Pentium 4 or G4 processor with a video and sound card and your internet connection should be at least 128 kpbs-no dial up.

Chatting over the internet can be a fun and productive way to interact with others.

Eriani Doyel writes articles about Chat Rooms. For more information about video chat visit www.figarden.com

How Cable Modems Work

Basic explanation of DOCSIS

So you have a broadband connection at home/work and are wondering how it all works. Well I hope to explain to you how it works on a low-tech level so you will have a better understanding of how your connection works. Broadband services from cable companies or Multiple Service Operatorรขโ�ฌโ�ขs (MSOรขโ�ฌโ�ขs) are normally provided via cable modems and 90% of the cable modems are using DOCSIS (Data over Cable Service Interface Specification). So letรขโ�ฌโ�ขs now look at what DOCSIS is and what is means. DOCSIS defines interface requirements for cable modems involved in high-speed data distribution over cable television system networks (definition from cablelabs.com). With DOCSIS comes the different versions (1.0, 1.1, 2.0, & soon 3.0) and the limits for each version. We are not too worried with the versions and limits between the versions as consumers since we just want speed and security. But the important thing about DOCSIS is that itรขโ�ฌโ�ขs a standard that protects the consumer and vendors by forcing interoperability and keep the cost of equipment down. If the modems where proprietary then the consumers would have to pay a very high price for the modem or would be force to lease them from the MSOรขโ�ฌโ�ขs. Most MSOรขโ�ฌโ�ขs will allow you to use just about any cable modem that is DOCSIS certified. Now not all MSOรขโ�ฌโ�ขs will do this since they have to support all the modems on the plant with firmware upgrades and other issue with support but most of your well known modems should be supported.

Now for the CMTS & Node

Cable modems communicate with a device called a cable modem termination system (CMTS). The CMTS is a router that talks to all the cable modems and routes there traffic to the internet or the MOSรขโ�ฌโ�ขs backbone. There are a few different vendors in the CMTS market but the most recognized is Cisco Systems. Cable modes are typically grouped into regional nodes. A node is most likely your subdivision but could but a smaller or lager area the MSO uses to support all you services. The node is a fiber to RF converter which allows the MOS to send services to you area via fiber up to the point of you local service area and them the services are sent over coax. The size of the node and number of modem customers in that node can make some difference in the speeds of you modem. With cable modems the node is you local access point and the more users the less bandwidth available for all. Most MSOรขโ�ฌโ�ขs over subscribe nodes but try to make sure there is always 50% available bandwidth at peak hours. What this means is that if you are in a heavily loaded node and everyone is downloading files you service can slow some. With how competitive the ISP business is most MSOรขโ�ฌโ�ขs will try to not over subscribe nodes to much with out adding more nodes or splitting then.

Security on the Network

Other things to watch out for is the security of the node. Make sure other subscribers in your node are not able to see you computer and its traffic. This security issue is normally handled by encryption on the modems traffic to the CMTS. Most ISPรขโ�ฌโ�ขs use BPI+ encryption to protect you traffic but you should always use a hardware firewall/router off of any broadband connection. To test the security of the node you can open your windows network places and look to see if any unknown shares are listed. If there is no encryption in the node and youรขโ�ฌโ�ขre on the same subnet you might be able to see other userรขโ�ฌโ�ขs network shares. This is bad if you have pictures or other sensitive data you do not want others to see. Other things to know are that most MSOรขโ�ฌโ�ขs will block ports to your computer network. This is for both there business goals and your protection. MSOรขโ�ฌโ�ขs typically block NetBIOS, SMTP, port 80, and a lot of other virus ports (business accounts may not have port filters). The port blocking is done mostly to protect the customers from viruses and worms that travel quickly over broadband connections.

Signal Levels and Splitters

Letรขโ�ฌโ�ขs now look at the signal level needed to keep your cable modem online and surfing. Most cable modems have a signal range that they need to communicate to the CMTS. The signal levels can differ from vendor to vendor but as a rule of thumb most modems work well from RX -10dbv to +10dbv and TX 40dbv to 56dbv. A lot of modem vendors provide an informational webpage or diagnostic page you can connect too on the modem to see the messages from the modem and itรขโ�ฌโ�ขs levels. The diagnostic pageรขโ�ฌโ�ขs IP is different from modem to modem but if you lookup your vendors modem specifications you will be able to see if you modem has this diagnostic page available. Other things to keep in mind is that your cable modem should be on its own coax line from the cable audit box outside or from the main feed you get from the MSO. Itรขโ�ฌโ�ขs not a good idea to have your modem on a coax line with a lot of splitters due to each splitter has at least 3.5dbv or loss. And if you have to use a splitter make sure you read the throughput ratings on the splitter it should be at least 5-1000 MHz pass though. I hope this basic look at cable modems has helped you better understand how it al works and if you would like to find out more information about DOCSIS, CMTSรขโ�ฌโ�ขs, or cable modems try to use Google.

Brian Wilson
CCNA, CSE, CCAI, MCP, Network+
Slimjim100@gmail.com http://www.middlegeorgia.org http://www.middlegeorgia.info