The IP Evolution

Security over the network comes with challenges and accolades

Up until about 2004, analog-based security cameras were the default choice for many enterprise and data center customers. But by 2010, IP-based cameras began to overtake those analog-based designs. The market transition occurred because of several advantages of IP-based systems including, lower cost of ownership, one cable plant supports both and connect, control, converge and power by moving to everything IP.

All of the above-mentioned advantages mentioned are similar to the adoption of VoIP technology. By using the IP network for both voice and data, the user not only eliminates the need for two disparate systems, but they also eliminate the need for two separate support teams. Additionally, like with VoIP, the IPbased video surveillance system can also be powered via Power over Ethernet (PoE) technology. This eliminates the need for a separate dedicated power circuit to support each device—a huge cost savings.

A few other advantages with IP-based systems worth mentioning are remote access anytime, anyplace; digital images do not degrade over time; real time analytic capability; and content distributed electronically quickly and easily.

However, even with the numerous advantages that IP-based systems offer, there are some new concerns that must be accounted for that weren’t relevant with analog-based systems. Among them is protecting the connected IP network from remote hackers located anywhere in the world who are able to gain unauthorized access to the system. A robust network security software that is continually updated to protect against new threats is a must.

Another is bandwidth capacity consumed. As the resolution of cameras continues to increase, more network bandwidth is consumed to support each camera. This also leads to an increase in the available storage capacity required. Both concerns of storage capacity and available network bandwidth can be eliminated with proper planning and investing in the appropriate equipment. But increasing bandwidth also demands more from the network infrastructure.

The focus of this article will be to illustrate what new HD and UHD technologies incorporated into IP surveillance video cameras mean to the network infrastructure. It will also discuss recommended solutions to support advanced video surveillance systems.

Network Bandwidth and IP Video Surveillance

There are several factors that affect bandwidth requirements from the network.

Resolution. The resolution of IP surveillance cameras varies widely. There are VGA resolutions (600x480 lines of resolution) up to 8.3 MP cameras which can capture 4k video quality. The higher the resolution, the more bandwidth each camera will require from the network and the greater the stress placed upon the network infrastructure.

Frame rate. The human eye cannot discern above 24 fps (frames per second) approximately. For reference, Ultra High Definition (UHD) movies are broadcast at 30 fps. Typically, in a video surveillance application, cameras are set to capture anywhere between 8 fps and 20 fps depending on several factors. If the camera will be recording high speed motion, a higher frame count is needed. If the camera will be operating in low light environments, a higher frame count is also needed. The higher the frames per second, the more bandwidth required.

Streaming mode. There are generally two options with today’s IP surveillance cameras. They are Constant Bit Rate (CBR) and a Variable Bit Rate (VBR). For CBR, this streaming mode streams at a constant rate. This mode is primarily used when monitoring a relatively stable environment, with limited motion and activity. Conversely, VBR is used when monitoring a highly active environment, and the bit rate increases as the activity level increases. This mode requires access to much more bandwidth during periods of high activity than that of a CBR streaming mode.

Compression. Compression is done by a device or software called a CODEC (COder/DECoder or COmpression/DECompression). In IP video surveillance applications, the CODEC is inside the camera. There are several compression technologies available, and they each have their advantages and disadvantages. Some compression technologies use what’s called a predictive frame approach. This means that if nothing changes from frame to frame, the CODEC only transmits what has changed in order to minimize the bandwidth required. The other main type of CODEC uses a transformative approach. In this approach, the CODEC chops the images into manageable chunks before actually compressing it. Some of the most popular compression technologies include MPEG-1, MPEG-2, MPEG-4, and H.264, with H.264 being the most popular for IP video surveillance applications.

It is beyond the scope of this article to elaborate in detail about each CODEC. However, it is worth noting that the CODEC used can have a big effect on the bandwidth required. Changing the CODEC from MPEG to H.264, for example, can reduce bandwidth requirements more than 50 percent. Incorporating compression technologies over IP networks can reduce bandwidth requirements, but it also means that each frame is critically important. Frame errors can have devastating consequences for an application like video surveillance, so a robust network infrastructure is very important.

Network protocols. When transmitting information over IP networks, there is always a balance to be struck between latency and reliability. In applications that are not as time-sensitive, like data transmission for instance, typically employ a protocol like Transmission Control Protocol (TCO/ IP). With TCP/IP, if the receiving device determines there are packet errors, it will buffer the data and request a resend from the transmitting device. Upon successful delivery of the resent packets, the receiving device will reconstruct the packet transmission and display the information.

Therefore, the TCP/ IP protocol prioritizes reliable delivery over latency. In other applications, like VoIP and video, where there is extreme time sensitivity, then protocols like Real Time Protocol (RTP), or User Datagram Protocol (UDP) are used. When using RTP or UDP, packet errors are simply dropped until error free packets are delivered. The user will notice the dropped packets as the image or audio will be distorted or turn off temporarily until error free packets are received again. RTP and UDP prioritize latency over reliability. The compression technology H.264 for example is usually transmitted with UDP or RTP protocols. Again, a high- quality network infrastructure is critical to video surveillance application and can contribute to minimizing packet errors.

IP Video Application Testing

The TEK Center at Berk-Tek conducted testing to determine how well different structured cabling infrastructures supported high definition and ultra-high definition video in various conditions. TEK Center engineers prepared bundles of several different cables: LANmark-XTP (Cat 6A), LANmark-10G FTP (Cat 6A), LANmark 10G2 (Cat 6A), and Generic Cat 6 cables.

The bundles were set up in a 6-around-1 configuration, as illustrated in Figure 1. Each bundle was made up of seven cables, and the cable in the middle (called the victim cable) experiences the worst case alien crosstalk possible. The surrounding six cables are called the “disturbers.” The cable bundles were then configured into 100 meter, four-connector channels. Please see

Every cable of every bundle was first tested with a Fluke DSX-5000 field test unit to ensure each met the Cat 6 or Cat 6A performance accordingly. After successful performance testing, the TEK Center began testing by energizing only the victim cable while transmitting in either 1080p or 4K UHD. Each test was repeated 12 times for statistical confirmation. Then, the test was repeated, but the six disturbers were also energized with 10GBASE-T traffic (similar frequency to UHD) to find what happens when alien crosstalk develops within the 6-around-1 cable bundle. This testing was also repeated 12 times. Table 1 illustrates the test results.

The TEK Center used Quantum Data’s 780C Multi-Interface Interoperability Tester (seen in Figure 2), which was originally released in June 2014. The test unit provides “Results of Confidence” which is a near-instantaneous measurement used to determine if the channels under test will provide satisfactory performance. Both 1080p and 4KUHD transmissions were tested. Please note that Quantum Data states that the 780C has a maximum reach of 75 meters when measuring 4K transmissions. Therefore, the 100m 4K test results are not considered relevant because they are beyond the distance capabilities of the test unit at the time of the testing (February 2016).

In order to compensate for the test unit, the TEK Center shortened the channel to 75 meters, and two-connector channels were used for 4K transmissions. The results of the 75-meter, two-connector channel testing can be seen in Table 2 below.

Then, the TEK Center turned up the heat. In environments like hot plenum spaces (think Arizona summertime), combined with up to 100W of PoE, the cables toward the center of the bundle especially will get hot. Heat creates higher attenuation that will negatively impact performance. The TEK Center tested all bundles in the two-connector 75 meter channel test configuration at 75-degree C (167-degree F), to which all Berk-Tek cables are listed. The results can be seen in Table 3.

Two solutions, LANmark-XTP and LANmark-10G FTP, are listed to 90-degree C (194-degree C), so the TEK center tested both to that temperature as well. The results are shown here in Table 4.

Structured Cabling Recommendation

An important point to note is that, while Category 6 and 5e are installed today to support IP video surveillance, the probability for success decreases significantly (as demonstrated by the TEK Center’s testing) with any of the following.

  • When multiple cables are bundled and transmitting 1080 HD or especially 4K UHD.
  • The closer to the maximum length of 100 meters.
  • Any electromagnetic noise sources close to the structured cabling (fluorescent light ballasts, power cables).
  • Operating environments where elevated temperatures occur.

When transmitting high definition, ultra-high definition or beyond, alien crosstalk (cable-to-cable noise) starts to become a significant factor. The structured cabling system has to be designed to account for alien crosstalk, especially when cables are bundled, and unfortunately Category 6 products were not designed for this. Additionally, the structured cabling system will most likely also be carrying power (up to 100W) to energize the display monitor eliminating the need for a separate outlet. This will elevate the temperature (especially in a cable bundle), further stressing the network infrastructure.

This article originally appeared in the November 2017 issue of Security Today.

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