The last part of our series on “designing your own security network” involves assessing your network needs i.e. local area network (LAN) and wide area network (WAN) 

What are you or the company using LAN for?

Measuring the level of congestion on a LAN is not as painful or as demanding as you would have initially thought. Today there are software and hardware tools available to measure the level of congestion on a LAN, such as Fluke Network’s EtherScope™ Series II Network Assistant and OptiView™ Series II Intergrated Network Analyzer

Assessing the company’s use of WANs (geographically dispersed networks).

It is quite possible (especially with larger companies) that you may have WANs that span between several office buildings. Fluke Network’s Visual UpTime® Select™ has recently launched product designed especially for this purpose.

What are you looking for? 
Ideally you want to gain an understanding of the congestion and note any patterns. For instance network traffic at a location may drop off at night and over weekends. Once a pattern is identified you can determine if it is possible to:      

1. Stick with the existing network infrastructure to add video surveillance equipment i.e. keeping with the same cable and cable outlets, and routers.    
2. Go with a combination of old and new, by using the existing general purpose network and a new network for IP-Surveillance  
3. Have a separate network altogether which is solely for IP-Surveillance purposes.  

If after the assessment you deem it necessary for additional network capacity, new cabling is normally not needed. In most instances this simply involves a router being added, or the reconfiguration of one of the patch panels.  

Other considerations:  

• If there is mission critical data, you may want to have a backup Internet connection.  
• Storage of recorded video can be distributed at local and distant sites to conserve bandwidth, as well as for security purposes.  
   

1. Using existing LAN with little upgrade to capacity

When there is enough capacity on the network, when your application requires little security, simply add network video equipment onto the existing network. You can further optimize your network using technologies such as VLAN or Quality of Service.

Good technologies to use in a LAN 

A good way to separate the surveillance network from the existing network is to use  a VLAN or virtual local area network.  A router can be configured to give a range of IP addresses, each with assigned features. Physical location will not be a limiting factor - all those in video surveillance VLAN A will have access to the video while those on the general purpose VLAN will not.

Quality of Service (QoS)

QoS ensures that the surveillance equipment has enough bandwidth to operate correctly on the existing network. Your network engineer will be able to set the level of priority for specific ports on a router. Remember to keep all connections to network cameras and storage servers set to high priority at all times,  while desktops can be set for low priority. This way you can be sure that there will always be bandwidth available for critical surveillance video.

Make Use of Existing WANs

VPNs are allow data to be sent in an encrypted form – the perfect chose for a surveillance system.

Distributed Storage

Local storage sites can be set to record at higher frame rates, while the monitoring centre at HQ only needs to record at lower frame rate. Recorded footage can then be transferred.    

2. Combination Network

Some of you may find yourselves in a situation where it more practical to implement a network that is dedicated to IP-Surveillance, that is in sync with the already existing network. Let’s use an example.

A company HQ implements a dedicated IP-Surveillance network in light of new bandwidth and security needs. Footage from the cameras are recorded locally and video traffic is isolated to that allocated particular network, except in the instance where a viewer on the general purpose network needs to access the footage or when an event is triggered to send video over to a user on the general purpose network.

Since access to video via the general purpose network (and the extra load it causes) is temporary, it makes sense to have the two networks work in combination.   
Tip: When building a new network or planning additional capacity for an existing network, always bank on using 30% to 40% more capacity or Mbps than first estimated.

3. A Separate network for IP Surveillance

If you go down this route the key thing to remember is to keep the it separate from other networks. Its to your advantage to outfit the IP-Surveillance network with its own routers that are in turn connected to a high capacity (backbone) that can handle the video traffic.