1. NVR Recording and Network Considerations
vicon-security.com
Video Security Design Workshop:
NVR Recording and Network Considerations
Vicon A&E Summit 2011

2. New Technology – New Issues
Newest Generation of IP Video Systems Presents New Challenges:
Systems are entirely IP
They include megapixel cameras with significantly higher picture resolution
Ease of connectivity is facilitating more cameras-per-system
Need for More Resources!

3. How Network and Storage are Affected
Demands of IP video systems put an increased load on:
The network carrying the video
The storage holding those recordings
Analogies to describe the situation:
Cars on a road heading to work
Water in a pipe heading to a pool

4. Bandwidth = Traffic
A road can handle only so many cars. A network can carry only so many bits.
To move more cars, we need more lanes. To move more bits, we need more bandwidth.

5. Storage = Parking Lot
Parking lots can hold only so many cars. Hard drives can hold only so many video files.
Once the lot is full, parking more cars requires:
Expanding the parking lot
Having some cars leave to make room for new cars
Once a hard drive is full, we can either:
Add more storage capacity
Remove older video files to make room for new recordings (Shorten the number of days video is kept)

6. Water Pipe Analogy Hose = Bandwidth Swimming Pool = Storage
Puppy = ???

7. Design Considerations
For Each Camera:
How many FPS is really necessary?
What resolution is required?
For Storage:
How much is required given above camera requirements and number of days storage
For Network:
How to best use technology to create an efficient system?
Work with IT to maximize the network traffic and optimize storage

8. IP Cameras on the Network
IP camera-based systems require more bandwidth
Megapixel cameras need even more
Consistent, reliable system performance requires network planning
Recommendation:
Video transmission may consume up to 70% of total network bandwidth
(i.e., 1000 Base/T network can provide about 70 Mbps for video transportation)

9. Parameters that Affect Bandwidth
Resolution
The higher the resolution, the higher the bandwidth:
Frame Rate
1-30 fps per camera; higher FPS  higher bandwidth.
Motion Type
Higher motion (activity) in the picture (i.e., a casino floor) uses more bandwidth than medium motion (i.e., an office space)
Compression Format
H.264, MPEG-4, M-JPEG have varying requirements

10. Expected Bandwidth for a Single Frame

11. Network Configuration
How many cameras can the network support?
Output from the switch = sum of all camera outputs

12. Data Flow: Analog Cameras, DVR and Workstation
System Server
Nucleus
Analog Cameras
Analog Signal
iSCSI
Display Path: DVR to Workstation
Hybrid DVRs
Playback Path: DVR to Workstation
Storage
Recording:
Done on the DVR

13. Data Flow: IP Cameras, NVR and Workstation
System Server
Nucleus
IP cameras and Encoders
Display Path: Camera to Workstation
iSCSI
NVRs
Recording Path: Camera to NVR
Storage
Backup NVRs
Playback Path: NVR to workstation

14. Data Flow: IP Cameras & Virtual Matrix Display Controller
System Server
Nucleus
IP cameras and Encoders
Display Path: Camera to VMDC and to Monitor
iSCSI
NVRs
Recording Path: Camera to NVR
Storage
Backup NVRs
Playback Path: NVR to VMDC and to Monitor

15. Data Flow: IP Cameras & Several VMDCs
System Server
Nucleus
IP cameras and Encoders
Display Path: Camera to VMDC and to Monitor through another VMDC
iSCSI
NVRs
Recording Path: Camera to NVR
Storage
Backup NVRs
Playback Path: NVR to VMDC and to Monitor through another VMDC

16. Basic Calculations
Connecting 10, 20, or 50 cameras on the network? Assuming each camera outputs 2 Mbps, then…
10 cams X 2 Mbps = ~ 20 Mbps
20 cams X 2 Mbps = ~ 40 Mbps
50 cams X 2 Mbps = ~ 100 Mbps SO
When using a 100 Mbps switch
35 cams X 2 Mbps = ~ 70 Mbps = 70% capacity
This is the maximum recommended number of cameras.

17. Daisy Chain versus Star Topology
Cascading Switches
How many network switches are needed?
Systems with many IP cameras require multiple switches
Daisy Chain versus Star Topology
Which should you use?
Main
Switch 1 2 3 4 5
Switch 1
Switch 2
Switch 3
Switch 4

18. Daisy Chain Topology Assuming 100 Mbps switches 18Mbps 6Mbps 50Mbps
Too Many Mbps
18Mbps

19. Star Topology Assuming 100 Mbps switches 50Mbps 50Mbps 50Mbps
Possibly too many Mbps

20. Star Topology - Explanation
Using a 1000 Mbps (1 Gbps) switch:
IP cameras use a 100 Mbps network card
Connecting to a 100/1000 Mbps switch will utilize Mbps (1 Gbps) going out to the PCs
Whether the cameras can connect from smaller switches at 100 Mpbs to central switches at 1000 Mbps all depends on the accumulated bandwidth
Remember to make sure each and every switch has enough bandwidth to support its in/out needs!

21. Using 1 Gbps Switches
The main switch can output 1Gbps

22. Individual Streams
Every user gets an individual stream from the camera.
Data is fully acknowledged to protect from losing information.
Bottleneck on one viewer doesn’t affect the others.
2 Mbps
Wireless bridge
3X2 Mbps
≈ 6 Mbps
Wireless access point
Switch
2 Mbps
2 Mbps
4 Mbps

23. Multicasting Streams Each camera sends only one stream to the network
Special switch provides a copy of the stream to PCs who request it
Everybody gets the same stream regardless of their supported bandwidth
Multicast is UDP and not acknowledged
2 Mbps
Wireless bridge
2 Mbps
Wireless access point
Switch
2 Mbps
2 Mbps
4 Mbps

24. Switch Backbone and Output
Every switch has a certain specification
A 16 port switch with 1Gbps ports cannot support a full 1Gbps through each port simultaneously. Its “Backbone” is the total throughput capacity.
The more professional the switch, the stronger the backbone.
High end switch systems usually connect the central switches with a special connection or fiber to create a central backbone.
“Stacking” switches

25. Pure Gigabit Stack

26. Points to Remember What are the critical design points in the network?
Evaluate the expected bandwidth from each camera
keep in mind the number of concurrent users per camera.
Each switch’s output (to the next switch or NVR) must not exceed 70% of maximum bandwidth
Using the Star topology, add central switches with higher bandwidth.
Remember, every port on the switch has its own bandwidth, so if two workstations are connected to two different ports, each has its own 100 or 1000 Mbps.
In very high traffic network, invest in a strong central stack of switches with a strong backbone