A router could connect multiple CCTV cameras over a local area network (LAN) and provide access to the camera feeds from outside the LAN. The router would assign IP addresses to the cameras, allow remote access through port forwarding, and provide network address translation (NAT) to share a public IP address. It could also segment the CCTV network from other devices for improved security and prioritize camera traffic to ensure smooth video streaming. Properly configured, a router is key infrastructure to network multiple IP cameras and monitor their feeds remotely over the internet.

1. Networking
Introduction to Network Basics
By
Saeed Abdillahi

2. A network consists of 2 or more computers or
networked devices connected together, and they can
communicate and share resources (e.g. information)
What is a Network?

3. Sharing information — i.e. data communication
Do you prefer these?
Or this?
Why Networking?

4. Sharing hardware or software
•Centralize administration and support
• E.g. print document
• E.g. Internet-based, so everyone can access the same administrative or support
application from their PCs

5. How many kinds of Networks?
•Depending on one’s perspective, we can classify
networks in different ways
• Based on transmission media: Wired (UTP, coaxial cables, fiber-optic
cables) and Wireless
• Based on network size: LAN and WAN (and MAN)
• Based on management method: Peer-to-peer and Client/Server
• Based on topology (connectivity): Bus, Star, Ring …

6. Local Area Network (LAN)
• Small network, short distance
• A room, a floor, a building
• Limited by no. of computers and distance covered
• Usually one kind of technology throughout the LAN
• Serve a department within an organization
• Examples:
• Network inside the Student Computer Room
• Network inside Security room
• Network inside your home
LAN AND WAN

7. Wide Area Network (WAN)
• A network that uses long-range telecommunication links to connect 2 or
more LANs/computers housed in different places far apart.
• Towns, states, countries
• Examples:
• Network of Corporate offices
• Internet
WAN
Corporate Computer
Centre
Your home
UK

8.  Wi-Fi - WLAN (wireless local area network) based on
IEEE 802.11 specs (a,b,g,n,ac)
 • Uses wireless access points (WAPs) to transmit to
and receive from WiFI-enabled devices.
 • Most implementations operate in the unlicensed
spectrum near 2.4 GHz.
Wireless Networks

9. Network Terms defined
LAN – Local Area Network
• A LAN connects network devices over a relatively short distance.
• A networked office building, school, or home usually contains a single LAN,
though sometimes one building will contain a few small LANs (perhaps one
per room), and occasionally a LAN will span a group of nearby buildings.
• In addition to operating in a limited space, LANs are also typically owned,
controlled, and managed by a single person or organization.

10.  Two main categories:
 Guided ― wires, cables
 Unguided ― wireless transmission, e.g. radio,
microwave, infrared, sound, sonar
 We will concentrate on guided media here:
 Twisted-Pair cables:
Unshielded Twisted-Pair (UTP) cables
Shielded Twisted-Pair (STP) cables
 Coaxial cables
 Fiber-optic cables
Transmission Media

11.  If the pair of wires are not twisted, electromagnetic
noises from, e.g., motors, will affect the closer wire more
than the further one, thereby causing errors
11
Twisted-Pair Cables

12. Categories of UTP Cables
Electronic Industries Alliance (EIA) classifies UTP cables according to
the quality:
 Category 1 ― the lowest quality, only good for voice, mainly found
in very old buildings, not recommended now
 Category 2 ― good for voice and low data rates (up to 4Mbps for
low-speed token ring networks) – (Empty information frames are
continuously circulated on the ring)
 Category 3 ― at least 3 twists per foot, for up to 10 Mbps
(common in phone networks in residential buildings)
 Category 4 ― up to 16 Mbps (mainly for token rings)
 Category 5 (or 5e) ― up to 100 Mbps (common for networks
targeted for high-speed data communications)
 Category 6 ― more twists than Cat 5, up to 1 Gbps
12

13. Coaxial Cables
 In general, coaxial cables, or coax, carry signals of higher
frequency (100KHz–500MHz) than UTP cables
 Outer metallic wrapping serves both as a shield against
noise and as the second conductor that completes the
circuit

14. Advantages and Disadvantages
 Noise resistance ― external light is blocked by outer jacket
 Long distance ― a signal can run for miles without regeneration
(currently, the lowest measured loss is about ~4% or 0.16dB per
km)
 Higher bandwidth ― currently, limits on data rates come from
the signal generation/reception technology, not the fiber itself
 Cost ― Optical fibers are expensive
 Installation/maintenance ― any crack in the core will degrade
the signal, and all connections must be perfectly aligned
Fiber-Optic Cables

15. Peer to Peer
•Peer-to-peer network is also called workgroup
•No hierarchy among computers  all are equal
•No administrator responsible for the network
Peer-to-peer

16. • Network Clients (Workstation)
• Computers that request network resources or services
• Network Servers
• Computers that manage and provide network resources
and services to clients
• Usually have more processing power, memory and hard disk
space than clients
• Run Network Operating System that can manage not only
data, but also users, groups, security, and applications on the
network
• Servers often have a more stringent requirement on its
performance and reliability
Client / Server

17.  On most basic networks you will find the following
devices
 Computers Modems
 Switches Routers
 Printers Network Drives
 Hardware Firewalls Wiring
 Network Interface Controllers (NIC’s)
 Cameras Wireless Access Points
Networking devices

18.  802.11a (rare – 54 Mbps max, 75 feet max, uses 5 GHz
band– Lower interference, higher signal attenuation
 802.11b (first and most popular standard)– 11 Mbps max,
150 ft max, 2.4 GHz, lowest cost– Interference from
cordless phones and microwave ovens
 802.11g (current leader in new sales) – 54 Mbps max, 150 ft
max, 2.4 GHz band– Backwards compatible with 802.11b
 802.11n – 540 Mbps max, 160 ft max, 2.4 or 5 GHz– MIMO -
multiple-input, multiple-output (uses multiple antennas)
 802.11ac -
Wireless “Flavors”

19.  Hubs and switches connect multiple Ethernet devices
together
 Hub – repeats the signal received at one port out
each of the other ports (broadcast)
 Switch – connects devices to form a local area
network (LAN), isolates ports, passing only data
meant for that port
How devices get networked?

20.  Acts as a junction between two networks to transfer
data between them – Between WAN (wide area
network) of Internet and LAN (local area network) in
home
 Provides additional networking and security features
– DHCP, NAT, DMZ, firewall, VPN
 Router devices also typically incorporate a switch
Network Router

21. Routers give multiple machines access to the internet under one external
IP address, whereas a switch is only a splitter. Compare the router to an
intersection with street signs, and switches as neighborhood streets.

22.  DHCP - Dynamic Host Configuration Protocol – Service that
automatically assigns IP addresses to connecting devices
 NAT - Network Address Translation – Allows the router to
present a single IP address to the Internet
 DMZ - Demilitarized Zone – Perimeter network that sits
between an internal private network and external public
network, protecting internal network from external attack
 Firewall – Security device that controls traffic between
networks with different levels of trust
Router Features

23.  IP Address—An IP address is a number that is assigned to
each computer on the network to help computers
communicate. Each device on the network should have a
unique IP address. Duplicate IP addresses may cause a
disruption in service. Your IP address may look like one of
the following: 10.0.x.x, 169.254.x.x, 172.x.x.x, or 192.168.x.x.
IP addresses in the 169.254.x.x are self-assigned (APIPA) and
may indicate a problem on your network.
IP Addresses

24.  Subnet Mask—The subnet mask describes the size of
your network and lets the router or client know which
devices are part of the local network and which
belong to a different network. In most cases, your
router will be set to a subnet mask of 255.255.255.0.
This allows you to create a network with up to 256
devices. Devices with self-assigned IP addresses will
have a subnet mask of 255.255.0.0. The subnet mask
helps your router decide on the most efficient way to
route network traffic between devices.
Subnet Mask

25.  Default Gateway - a default gateway is the device that
passes traffic from the local subnet to devices on other
subnets. The default gateway often connects a local
network to the Internet, although internal gateways for
local networks also exist. This will typically be your router.
Default Gateway

26.  NAT— Most home routers or gateways use a NAT
firewall to protect your home network from
intruders. NAT or Network Address Translation works
by hiding your computer’s IP address from Internet
devices and replacing it with the gateway IP address.
It will then forward Internet traffic to the proper
computer. To further protect your home network, the
NAT firewall disallows unrequested traffic from the
Internet.
NAT

27.  Port Forwarding— Some applications, such as Torrents and
Remote Access, require unrequested inbound connections. To
use these features or connect to your device on the network,
you will need to configure your router to allow inbound
connections for these applications. This is known as Port
Forwarding. Port forwarding is an extension of NAT that allows
external traffic to pass through a specified port to an internal
device. In some cases the router may be integrated into an
Internet gateway that handles the roles of modem, router, and
switch. In most cases your home network should only have a
single router. Extreme caution should be taken when
introducing a second router into a network since it may disrupt
some services. If your network has more than one router, steps
should be taken to ensure that DHCP and NAT services are
disabled on the secondary router to avoid Internet network
problems.
Port Forwarding

28.  DDNS – A DDNS is a service that maps Internet IP
addresses to a domain name,
 Example. saeed.abdillahi.com
 This name would be associated with a specific IP
address.
DDNS

29. Ex. Client Server Network

30. Typical Network Layout

31. Router in Network

32. Now Thank You!apply
this to CCTV?