- What does IP mean?
- How is IP carried on a network?
- Does IP protect data on the network?
- Are all network IP cameras the same?
- Why choose a network IP camera over a web camera?
- What is the advantage of the embedded OS?
- Do I need a public fixed IP address for each camera?
- How does the built-in motion detection work?
- What is Power-over-Ethernet (PoE)?
- Can network IP cameras use different lenses?
- What image sizes can be viewed from network IP cameras?
- What does Lux mean?
- What is DDNS?
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1. What does IP mean?
The most prevalent transmission and switching technique being used today is IP (Internet Protocol) / Ethernet. IP/Ethernet was originally designed for the LAN but is also migrating into the MAN etc. This technology accounts for over 80% of all installed LANs today. In addition, over 90% of the devices in these networks are IP enabled i.e. they can be found by their IP address. |
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2. How is IP carried on a network?
IP really isn't very fussy about how its packets are transported. The details of how an IP packet is carried over a particular kind of network are usually chosen to be convenient for the network itself. As long as the transmitter and receiver observe some convention that allows IP packets to be differentiated from any other data that might be seen by the receiver, then IP can be used to carry data Between those stations. IP itself does not guarantee to deliver data correctly. It leaves all issues of data protection to the transport protocol. Both TCP and UDP have mechanisms that guarantee that the data they deliver to an application is correct. |
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3. Does IP protect data on the network?
IP does try to protect the packet's IP header, the relatively small part of each packet that controls how the packet is moved through the network. It does this by calculating a checksum on the header fields and including that checksum in the transmitted packet. The receiver verifies the IP header checksum before processing the packet. Packets whose checksums no longer match have been damagedin some way and are simply discarded. |
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4. Are all network IP cameras the same?
No, some network cameras have an embedded OS (operating system) as well as an embedded Web server. To be called a Network IP camera, the only requirement is that the camera connects to the network, and not a computer - an embedded OS is what separates network cameras. |
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5. Why choose a network IP camera over a web camera?
An IP Camera is a true networking device containing an embedded OS (Operating System), supports multiple users, and can be viewed Using any web browser. It does not require additional hardware to operate and therefore has the flexibility to be located anywhere with a network connection. A web cam must be connected to a host computer, supports only one user at a time, and cannot be shared on a network. Only the host computer can access the web cam. |
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6. What is the advantage of the embedded OS?
Cameras with an embedded OS communicated directly with the user, the images or video is sent directly from the camera to the Person accessing the camera. A Network camera without an embedded OS must rely on a third party server or a separate piece of software, meaning the images/video is sent to the third party server, then the user access the image from the third party server. |
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7. Do I need a public fixed IP address for each camera?
No, you of course, can have a real, public, static IP address for each camera, however, using just one static IP address for your router and a virtual server or port forwarding scheme, you can use many cameras with just one static IP and just about any router. Please also note that the IP camera must have an adjustable web server port that you can change to use multiple cameras behind a router. |
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8. How does the built-in motion detection work?
Motion detection works with a relatively simple algorithm, take a snapshot and subtract it from a reference frame. Every pixel that is not zero is a change. Next, all changes above a certain noise level are counted, if the result is above a certain threshold it is declared a motion. Slow light changes (sun moving during the day) are not detected because the reference picture is constantly updated with the new image after motion detection. The average of the two is used as the new reference frame, so the reference frame will consist of ½ frame(n-1) + 1/4 frame(n-2) + 1/8 frame(n-3) and so on. |
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9. What is Power-over-Ethernet (PoE)?
Power-over-Ethernet (PoE) or "Active Ethernet" eliminates the need to run power to devices on a wired LAN. Using Power-over- Ethernet, installers need to run only a single CAT5 Ethernet cable that carries both power and data to each device. This allows greater flexibility and significantly decreases installation costs in many cases. |
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10. Can network IP cameras use different lenses?
Advanced Network IP Cameras utilize CS-mount lenses, which can accommodate a variety of specialized lenses, such as wide-angle, fish-eye or telephoto lenses. |
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11. What image sizes can be viewed from network IP cameras?
Advanced Network IP Cameras use multiple pre-set image sizes that typically include 160 x 120, 320 x 240 & 640 x 480 pixels. |
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12. What does Lux mean?
Lux (1/10 of a foot candle) is a standardized method by which to measure a security camera's sensitivity to light. The lower the number, the less light it will take to reproduce a clear image. For example: A securtiy camera that sees down to 1 LUX, means it generally has the ability to see an image during early evening hours or just before dusk. A security camera that's down to .1 has the ability to see an image in let's say, a well lit parking lot. A rating of .05, the ability to clearly view an image in a dimly lit area at night. A .05 image can usually enable a security camera to actually see better than the human eye at night! |
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13. What is DDNS?
DDNS is a service that maps Internet domain names to IP addresses. DDNS serves a similar purpose to DNS: DDNS allows anyone hosting a Web or FTP server to advertise a public name to prospective users. Unlike DNS that only works with static IP addresses, DDNS works with dynamic IP addresses, such as those assigned by an ISP or other DHCP server. DDNS is popular with home networkers, who typically receive dynamic, frequently-changing IP addresses from their service provider. To use DDNS, one simply signs up with a provider and installs network software on their host to monitor its IP Address. |
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