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CCTV Digital Basics

Unit Unit 33 – Networks – Networks


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Objectives

Department

After completing this unit, you will be able to:

Define the elements of network traffic

Describe how network traffic is controlled and checked

Define Bits and Bytes, and their relationship

Convert Bytes to Bits

Describe bandwidth and how it impacts network traffic

Calculate network bandwidth requirements

Identify and describe the functions of different network

components

Unit 3 – Networks


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Department

Unit 3 – Networks

Factors to consider for network CCTV

The size of the security network• Number of cameras, and monitoring points• The extent of the network system (LAN, WAN)

Functions of security system• Monitor only for observations• Monitor for identification and security control of

environment Type and capacity of network

• Bandwidth of network components• Firewall and network security issues• Network traffic volume


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Department

Unit 3 – Networks

Network building blocks

Computer and operating system software

Network Interface Card (NIC)

Network connectivity

Network peripherals


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Department

Unit 3 – Networks

Three Basic Types of NetworksClient/Server network:

• Servers - Share resources such as files, printers, memory space and by their ability to connect to other network systems.

• Clients - Computers configured to use the resources of server computers.

Peer-to-Peer network:• Every computer is an equal and can function

as a client and a server. Networks limited to 10-15 computers on a single LAN system.

Point-to-point network:• The most basic type of network with a direct

connection between two computers only.


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Unit 3 – Networks

Half-duplex vs. Full-duplex

Half-duplexing – Network communications going in only one direction at a time.

•Most LAN systems

•Coax cable

Full-duplexing – Network communications going in two directions at the same time.

•Most WAN systems

•Separate channel required

•Twisted pair or fiber optics


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Unit 3 – Networks

Bandwidth

Analog Bandwidth – Measures the difference between the highest and lowest wavelength frequency. Hertz is the measurement used.

Digital Bandwidth –Measures the data transfer rate of data within a set time period (sec.) Bits/second is the measurement used.


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Unit 3 – Networks

Bytes to Bits Conversions

Bytes = File sizes (10 MB), Hard drive size (100 GB)

bits = Data transfer rate, bandwidth (56 Kbps, 10Mbps)

There are usually 8 bits in every Byte. Multiply the Byte file size X 8.

15,000 Bytes x 8 = 120,000 bits (120K)


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Unit 3 – Networks

Calculating Digital Video Bandwidth

Determine video output (bps)

(Video signal size X #* bits) X IPS = Video output

(15,000 X 8) X 30 ips = 3,600,000 bits/sec (3.6 Mbps)

Camera requires 3.6 Mbps bandwidth

* The number of bits is determined by the digital processor. In this example an 8 bit processor is used.


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Unit 3 – Networks

Network Capacity for Video

How many cameras can a network take?

About 65% of network bandwidth is available

1. Network Bandwidth X 65% = Usable bandwidth

100,000,000 X 0.65 = 65,000,000 bps maximum

2. Available bandwidth / Camera bandwidth = Maximum video connections allowed

65,000,000 / 3,600,000 = 18 camera connections


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Unit 3 – Networks

Network Communications

• There is a continuous stream of data traffic on networks (35% volume). Checks for network connections, device availability, routing information, self diagnostics.

• Data is sent in “packets” with “header” information.

• Who are you? (addressing)

• What type of device are you? (functionality)

• Where are you located? (routing)

• Do you speak my language? (protocols)

• Are we allowed to talk to each other? (security)


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Unit 3 – Networks

Network Communications

• There is a continuous stream of data traffic on networks (35% volume). Checks for network connections, device availability, routing information, self diagnostics.

• Data is sent in “packets” with “header” information.

• Who are you? (addressing)

• What type of device are you? (functionality)

• Where are you located? (routing)

• Do you speak my language? (protocols)

• Are we allowed to talk to each other? (security)

I am 161.88.16.2 nickname “training room”

I am a User PC

I am in subnet address 161.88.16.0

I communicate using TCP/IP

What is your password?


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Unit 3 – Networks

Protocols

Sets of rules or standards that controls or enables the connection, communication, and data transfer between two computing destinations.Some common network protocols:

Ethernet – Suite of protocols for LAN networks. 10Base-T (10 Mbps) – 1000Base-T (1000 Mbps)

TCP/IP – (Transmission Control Protocol/Internet Protocol) Suite of protocols based for both private networks and internet

UDP – (User Datagram Protocol) Uses IP and a subset of TCP. For small data packets, fast transmission rates by not checking packet information


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Unit 3 – Networks

International Communication Standards

Standards for sending voice, video and data over digital or normal telephone lines.

ISDN – (Integrated Service Digital Network) phone WAN systems. Between 128 – 384 Kbps.

DSL – (Digital Subscription Line) “Always on” WAN phone systems. 128 Kbps upstream, up to 8 Mbps downstream.

Often referred to as “last mile” technology to connect home/office to telephone switch. Not used between switching stations.


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Unit 3 – Networks

Network devices

Hub – A number of ports for connecting nodes on a LAN network. Sends the data to all connected nodes.


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Unit 3 – Networks

Network devices

Switch – Multiple ports that connect to different nodes.

Has memory and processing function that identifies IP addresses and directs the data to the specific addressed node(s).

Usually has more throughput than Hubs.


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Unit 3 – Networks

Network devices


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Unit 3 – Networks

Network devices

Routers – Connecting points between different network systems.

They direct the data to the specific addressed networks, and are “smart” in that they can identify the best transmission route.


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Unit 3 – Networks

Network devices


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Unit 3 – Networks

Network devices

Gateways – Function as an addressed node on networks and act as the entrance point to the network it has domain over.

Can function as both a proxy server and firewall.

Works with a Router to direct data to the proper IP addressed nodes.


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Unit 3 – Networks

Network devices


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Answer the review questions for Unit 3

Unit 3 – Networks


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Unit 1 – Defining Digital

Download - CCTV SYSTEMS Networks

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