Transcript NetworkDesignThoughts

Guy Arazi: Director of Product Management
• What is a virtual machine?
o A computer with the operating
system and added software that
does not run on dedicated
hardware
o Multiple VMs can run on the same
physical hardware server and
share its resources
o To the network, each PC seems
just like a stand-alone one
• Where does this meet our business?
o IT users purchase a very powerful hardware server and
attempt to run as many virtual PCs as possible
o The requirement to run NVRs on such machines is
growing
• This is less problematic for display stations (workstations and
VMDC) as these function more as user PCs and not servers
• Hardware cost is
shared by multiple
servers
• Redundancy solutions
can be offered
• Saves space, power
and HVAC resources
Disadvantages
•
Hardware cost is
shared by multiple
servers
•
Redundancy solutions
can be offered
•
Saves space, power
and HVAC resources
• Server prices are very high
• VMs tend to be under
powered if too many share
the physical server
• Setup and resource
allocation needs to be done
with attention to system
needs
• Where do we stand?
o Vicon neither tests nor approves specific VMs
• Where do we stand?
o Vicon neither tests nor approves specific VMs
There is an
unlimited
number of
combinations!
• Our Recommendation:
Ensure the VM meets the minimum requirements for an NVR
Verify you have a dedicated network card for the NVR - not
shared!
Verify you have a dedicated hard drive for recording shared!
not
The overall load on physical servers supporting NVRs is much greater
than on typical IT servers – more resources are required
Currently VM redundancy has not been tested but should be
supported
• Use the CAT cable from the network switch to push power to
the device and save the need for a power supply
• Standard is primarily meant for use on 100BaseT networks
• PoE enabled switch or mid-span can be used as the power
source
• Advanced standards allow High power PoE over a 1Gbps
connection as well
PoE enabled
switch
Network and
power on same
CAT cable
PoE IP camera
Regular switch
Network only on
CAT cable
PoE mid-span
Network and
power on same
CAT cable
PoE IP camera
• Still primarily designed for 100BaseT using 2 spare pairs in the
CAT cable
• PoE for 1000BaseT networks is available with certain distance
and power restrictions
• Provides 48 VDC
• Can provide up to 15.4W per channel (Standard PoE)
• External cameras with heater/blower usually require much
higher current
o Need to use a Power injector or Midspan with HighPower PoE
• Typical PoE switches have spec for their PoE power
• Most switches won’t offer full power on all ports
• Examples seen on specs:
o 24 port switch will offer 15.4W a port UP to 12 ports and 7.6W for more
o Some switches will state the total wattage (300W) and let you figure it our..
• Keep and eye on the camera power vs. switch to make sure you
don’t fall short
• Remember the heater and blower
• Existing analog systems tend to keep analog to avoid
new cabling
• There is a wide offering for IP over coax (with PoE)
• This solution similar to other “over the…” solutions allows
replacing analog with IP with a minimal pain
• The cost of the hardware is typically less than the new
cabling
• Demands of IP video systems put an increased load on:
o The network carrying the video
o The storage holding those recordings
• Analogies to describe the situation:
o Cars on a road heading to work
o Water in a pipe heading to a pool
• 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.
• 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:
o Expanding the parking lot
o Having some cars leave to make room for new cars
• Once a hard drive is full, we
can either:
o Add more storage capacity
o Remove older video files to
make room for new recordings
(Shorten the number of days
video is kept)
• For Each Camera:
o How many FPS is really necessary?
o What resolution is required?
• For Storage:
o How much is required given above camera requirements and
number of days storage
• For Network:
o How to best use technology to create an efficient system?
o Work with IT to maximize the network traffic and optimize
storage
• 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)
• Resolution
o The higher the resolution, the higher the bandwidth:
• Frame Rate
• 1-30 fps per camera; higher FPS  higher bandwidth.
• Motion Type
o Higher motion (activity) in the picture (i.e., a casino floor) uses
more bandwidth than medium motion (i.e., an office space)
o NOISE = MOTION
• Compression Format
o H.264, MPEG-4, M-JPEG have varying requirements
Network Configuration
 How many cameras can the network support?
– Output from the switch = sum of all camera outputs
• Connecting 10, 20, or 50 cameras on the network? Assuming
each camera outputs 2 Mbps, then…
o 10 cams X 2 Mbps = ~ 20 Mbps
o
20 cams X 2 Mbps = ~ 40 Mbps
o
50 cams X 2 Mbps = ~ 100 Mbps
SO
• When using a 100 Mbps switch
o 35 cams X 2 Mbps = ~ 70 Mbps = 70% capacity
o This is the maximum recommended number of cameras.
Assuming 100 Mbps switches
50Mbps
6Mbps
50Mbps
6Mbps
50Mbps
6Mbps
Too Many
18Mbps
Mbps
Assuming 100 Mbps switches
50Mbps
50Mbps
50Mbps
Possibly
too many
Mbps
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
1000 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!
• The main switch can output 1Gbps
Unicast of Individual Streams
2 Mbps
Wireless
bridge
– Data is fully acknowledged to protect
from losing information.
3X2 Mbps
≈ 6 Mbps
Wireless
access
point
– Bottleneck on one viewer doesn’t
affect the others.
Switch
2 Mbps
– Every user gets an individual stream
from the camera.
2 Mbps
4 Mbps
Multicast of Streams
2 Mbps
Wireless
bridge
2 Mbps
Wireless
access
point
– 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
Switch
– Multicast is UDP and not acknowledged
2 Mbps
2 Mbps
2 Mbps
• 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.
o “Stacking” switches
Points to Remember
What are the critical design points in the network?
• Evaluate the expected bandwidth from each camera
o
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