Power over Ethernet (PoE) and Network Bandwidth

November 19, 2010 by Nathan Miloszewski

Data transfer rate standards have increased dramatically enabling today’s Ethernet networks to provide the performance necessary for demanding IP video applications.

Power over Ethernet (PoE) provides the option of powering devices (IP cameras) connected to an IP network using the same cable that’s used for data communication.

While network bandwidth may have been a scarce resource in the past, today bandwitdth is plentiful but there are still a few things to consider when setting up a network for IP video surveillance.

Power over Ethernet

Power over Ethernet (PoE) lets you use the same Ethernet cable for supplying power and for transferring data.  The main benefit is the immense cost savings associated with this.  Hiring electricians to install separate power lines is unnecessary.  In addtion to that, PoE:

  • Makes moving IP cameras to new locations simple.
  • Adding additional IP cameras to your system can be done quickly.
  • Video system with PoE is more secure because most server rooms have an Uninterruptible Power Supply (UPS) allowing operation during power outages.

Network Setup For IP Surveillance

Network servers are very powerful these days with vast amounts of available bandwidth.  However, there are some considerations when setting up a network of IP video surveillance:

  • Is there existing cable?  If Ethernet cabling already exists, you’re ahead of the game and will save lots of money.  But make sure it’s quality is high enough to support the network speed you need and use of PoE.
  • What category cable is used?  If no existing cabling, you need to install cable.  Labor will be your biggest expense.  Get the best that you can afford to future-proof your installation.
  • Cable distances?  Fiber cables are best for distances over 100 feet.
  • PoE availability?  Use of PoE results in huge savings, look for devices that offer it.  If you are going to us PoE make sure the available power in the switch or midspan is sufficient.
  • Required Bandwidth?  Most network switches provide more bandwidth than necessary but to future-proof your network, design it so that only 30% of its capacity is used.
  • WAN connection?  The WAN (wide area network) bandwidth is limited – design your system so that the WAN bandwidth is not overloaded.
  • VLAN or, separate network?  VLAN’s generally provide a better and more cost efficient solution than a separate network.

Future Proof

Build your network with more capacity than is needed and you’ll always be safe as more and more applications are being run over networks and requiring higher performance.  And remember that network switches are easy to upgrade after a few years but cabling is more difficult to replace – so you want to make sure to do it right the first time around.


1 Comment

  • olarewaju gabriel

    I am designing a CCTV project that will need fiber optic cable to link all all the sight location at interver of 120km with a poi please help me.

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