CHAPTER FIVE: CONFIGURE NETWORK ADDRESSING

Question 1

How the Internet Works at a Basic Level

Answer 1

The internet is a massive network of networks—kind of like a global transportation system where data moves between locations.

The core of this system is made of fiber optic cables that send data as beams of light at super high speeds. These cables connect Internet Exchange Points (IXPs), which are like major hubs where different networks meet.

Internet Service Providers (ISPs) are the companies that give you internet access. They connect their networks to these major hubs so that you can reach websites, stream videos, and more.

Your ISP has a Point of Presence (PoP) near you—think of it as their local office where your internet connection starts.

To connect your home or office to the ISP’s network, you need a specific type of internet connection, which involves both physical cables (or wireless signals) and special devices like modems and routers to manage the connection.

Question 2

What is Digital Subscriber Line (DSL) – Uses Phone Lines?

Answer 2

DSL runs through the existing copper phone lines in your home, but it doesn’t interfere with your phone calls.

Since copper wires aren’t the best at carrying high-speed data, DSL speeds are slower than fiber or cable.

Question 3

What are the two types of DSLs?

Answer 3

Asymmetric DSL (ADSL): Faster at downloading than uploading (good for watching videos but not great for things like Zoom calls).

Symmetric DSL (SDSL): Upload and download speeds are the same, which is better for businesses that need to send a lot of data.

You need a DSL modem to convert the signals from the phone line into internet data.

Question 4

What is cable internet?

Answer 4

Cable internet is usually faster than DSL because it uses a hybrid system called Hybrid Fiber Coaxial (HFC)—fiber optic cables for long distances and coaxial cables for the short distance to your house.

A technology called DOCSIS helps manage and improve speeds, allowing some cable internet connections to reach speeds of 50 Mbps or more.

You’ll need a cable modem, which connects to the coaxial cable and then to your router.

Question 5

What is fiber internet?

Answer 5

Fiber optic internet sends data using light instead of electrical signals, making it super fast and reliable.

Question 6

What are two types of fiber internets?

Answer 6

Fiber to the Curb (FTTC): Fiber runs to a nearby cabinet, but the last part of the connection to your house still uses copper wires (like VDSL, a faster version of DSL).

Fiber to the Premises (FTTP): The fiber cable runs all the way to your house or office, giving you the fastest speeds possible.

Question 7

What are Passive optical networks?

Answer 7

Passive Optical Network (PON): This system splits the fiber connection to serve multiple homes from a single fiber cable.

You need an Optical Network Terminal (ONT) instead of a modem to convert the fiber signal into data your router can use.

Question 8

What are Fixed Wireless Internet?

Answer 8

In places where running cables is difficult (like rural areas), you can get the internet wirelessly from a nearby tower. This system uses radio signals similar to cell towers and requires a special receiver at your home.

Question 9

What is Satellite Internet?

Answer 9

If you’re in a remote area with no wired or wireless options, you can use a satellite dish to connect to the internet.

The dish communicates with a geostationary satellite (one that stays in the same spot in space) thousands of miles above Earth.

Since the signal has to travel a long distance, satellite internet has high latency (a noticeable delay), making it slower for real-time activities like gaming or video calls.

You need a VSAT dish and a DVB-S modem to use satellite internet.

Question 10

What is a modem?

Answer 10

Converts the signal from your ISP (DSL, cable, fiber, etc.) into data that your computer or router can understand.

Question 11

What is a router?

Answer 11

Sends that data to all your devices over Wi-Fi or Ethernet cables. Some devices combine both functions into one, like many home internet boxes that have built-in routers.

Question 12

What is LEO internet access?

Answer 12

Low Earth Orbital (LEO) Satellite Internet Access
Imagine a bunch of satellites zooming around the Earth in space. These satellites aren’t super far away like the old-school ones (called geostationary satellites); instead, they’re much closer—this is why they’re called Low Earth Orbit (LEO) satellites.

Since they’re closer, they can give you faster internet (about 70–100 Mbps, which is good for streaming and gaming).

They also have lower latency, which means there’s less of a delay when you click something online.

But, because these satellites are moving across the sky, your satellite dish at home has to keep adjusting itself to stay connected.

The dish does this using a phased array—a fancy tech that lets it talk to different satellites without needing to move too much.

To work properly, the dish needs an open view of the sky with nothing blocking it.

Question 13

What is WISPs?

Answer 13

Wireless Internet Service Providers (WISPs)
Instead of using satellites, a Wireless Internet Service Provider (WISP) uses radio signals from a tower on the ground to send internet to your home.

They install an antenna on your house that acts like a bridge between your network and the internet provider’s network.

It can use Wi-Fi-like signals or special radio frequencies.

It’s usually faster than satellite internet and has less delay (latency).

But here’s the catch: this type of internet needs a clear line of sight between your antenna and the provider’s tower. If something is blocking the signal—like trees or buildings—it won’t work as well.

If the provider uses unlicensed frequencies, there’s also a risk of interference (other wireless networks messing up your signal).

Question 14

What are Cellular Radio Internet Connections?

Answer 14

Wi-Fi works for short distances, but cellular radio covers much bigger areas.

Some Internet of Things (IoT) devices (like smart meters for electricity) also use this type of connection.

Cellular internet has different “generations” (or G’s):

Question 15

What is G3?

Answer 15

3G (Third Generation)
Uses cell towers to send internet signals.

Each tower covers an area called a cell (hence the name “cellular network”).

Has a range of up to 5 miles (8 km) but can be blocked by buildings.

Works on different frequency bands (850 MHz and 1,900 MHz in the Americas; 900 MHz and 1,800 MHz in other parts of the world).

Question 16

What are the two competing technologies of 3G?

Answer 16

GSM (Global System for Mobile Communication) → Uses a SIM card to store your network info.

CDMA (Code Division Multiple Access) → No SIM card; your provider manages your phone directly.

Question 17

What is 4G?

Answer 17

A big upgrade over 3G.

Uses LTE (Long-Term Evolution), a standard that works with both GSM and CDMA providers.

Faster speeds than 3G, making it great for streaming, gaming, and video calls.

Question 18

What is 5G?

Answer 18

Uses new frequency bands:

Low-band (sub-6 GHz): Travels far and can go through walls.

High-band (mmWave, 20–60 GHz): Super fast but only works over short distances (a few hundred feet) and can’t go through walls.

Needs many small antennas instead of one big tower.

Uses Massive MIMO (Multiple Input Multiple Output), meaning many antennas work together to improve the signal.

5G isn’t just for phones—it can be used for home internet and smart city technology too.

Question 19

What is Routers and Internet Protocol (IP)?

Answer 19

The Internet Protocol (IP) is the set of rules that helps data move around the internet.

Your router has two sides:

One side connects to your private network (your home Wi-Fi).

The other side connects to the public internet (WAN – Wide Area Network).

Question 20

How does data move?

Answer 20

Every device has a MAC address—this is like a fingerprint for its network card.

But MAC addresses are only for local networks. If your data needs to go further (like to a website), it needs an IP address.

Your router translates between MAC addresses (inside your home) and IP addresses (for the internet).

Question 21

The Basics of TCP/IP and Networking

Answer 21

Think of the internet like a giant postal system. Just like mail needs to be packed, labeled, and sent through different stops before reaching the final address, data on the internet also has to be packaged, addressed, and routed through different networks before reaching your device. That’s where TCP/IP comes in—it’s like the rules that make sure your digital “mail” gets delivered properly.

Question 22

What are the 4 Layers of TCP/IP?

Answer 22

1. Link Layer (Network Interface Layer)
2. Internet Layer
3. Transport Layer
4. Application Layer

Question 23

Define the link layer?

Answer 23

This layer is like the delivery trucks and roads in your local area. It deals with how data is physically sent over cables or wireless signals.

It doesn’t use TCP/IP directly but instead relies on things like Ethernet (wired internet) or Wi-Fi (wireless internet) to carry data.

Data here is packaged into frames, and devices are identified by their MAC address (like a unique postal code for your computer).

Question 24

What is the internet Layer?

Answer 24

Internet Layer
This is where addresses and routes come in. It’s like putting a mailing address on an envelope.

The Internet Protocol (IP) makes sure data is labeled with an IP address (just like your home address) so that it reaches the right place.

If data needs to jump between different networks, it goes through a router (like a postal sorting center).

But how does the network know which MAC address (local postal code) belongs to which IP address (big city address)? That’s where Address Resolution Protocol (ARP) helps—it translates IP addresses into MAC addresses.

IP is unreliable—data can get lost, show up late, or even be duplicated (like a letter getting lost in the mail).

Question 25

What is the transport layer?

Answer 25

Transport Layer Now we’re dealing with how conversations happen between devices. Imagine sending multiple letters to different friends—you don’t want them to get mixed up. This layer makes sure different applications (like YouTube, email, or gaming) can send and receive their own data without interference.

Question 26

What are two delivery methods for the transport layer?

Answer 26

Transmission Control Protocol (TCP): Like registered mail, it guarantees delivery, tracks lost packets, and makes sure everything arrives in the right order. Great for important stuff like emails or loading web pages. User Datagram Protocol (UDP): Like sending postcards—it’s faster but doesn’t check if every single packet arrives. Used for real-time things like video calls or online gaming, where minor glitches aren’t a big deal.

Question 27

define the application layer?

Answer 27

Application Layer This is where actual applications (like web browsers, email, or video streaming services) use TCP/IP to communicate. Every application uses specific ports (like different mailbox slots in an apartment building) to keep data separate and direct it to the right program.

Question 28

What is IPv4 Addressing?

Answer 28

Every device on the internet has an IP address (like a phone number or home address). The standard IPv4 address is made up of 32 bits, but that’s hard to read. Instead, it's broken into four groups called octets and converted into a human-friendly format, called dotted decimal notation (like 192.168.0.1). The lowest possible IP address is 0.0.0.0, and the highest is 255.255.255.255, but some are reserved for special purposes.

Question 29

Network Prefixes (How IP Addresses Work)

Answer 29

An IPv4 address is like a mailing address for your device on a network. It tells computers two things: 1. Network ID – Think of this as the neighborhood where the device lives. 2. Host ID – This is like the house number within that neighborhood. To separate these two parts, we use something called a network prefix. This is just a way to say, “These first few numbers belong to the network, and the rest belong to the device.” A prefix is written as something like /24, which just means "the first 24 bits are the network ID." This can also be written as a subnet mask, like 255.255.255.0 (which is just another way of saying how many bits belong to the network).

Question 30

What is IPv4 Forwarding?

Answer 30

When your device sends data over the internet, it follows these steps: 1. It checks its own IP address and subnet mask to figure out if the destination is on the same network. 2. If the destination is on the same network, it sends the data directly. 3. If the destination is on a different network, it sends the data to a default gateway (which is just a router that knows how to forward data to other networks). A default gateway is like a post office that knows where to send your mail (data) when it's not meant for someone in your neighborhood.

Question 31

What is a public address?

Answer 31

These are assigned by Internet Service Providers (ISPs) and are unique worldwide.

Question 32

What are private addresses?

Answer 32

These are used within local networks and are not unique (many people can use the same private IP addresses in their own networks). Network Address Translation (NAT) to convert private addresses into public ones.

Question 33

Internet Access Using Private Addressing

Answer 33

NAT (Network Address Translation) – A router replaces private IPs with a public IP when sending data online. Proxy Servers – These act as middlemen, fetching data from the internet for private network users.

Question 34

IPv4 Host Address Configuration (How Devices Get Their IPs)

Answer 34

For a device to communicate on a network, it needs at least two things: An IP address (e.g., 192.168.0.100) A subnet mask (e.g., 255.255.255.0) To fully connect to the internet, it also needs: A default gateway (e.g., 192.168.0.1), which is the router that sends data to other networks. A DNS server (which converts website names into IP addresses, so you can type “google.com” instead of an IP address).

Question 35

What is static IP addressing?

Answer 35

Static IP (Manual Setup) – You type in the address yourself. This is good for things that always need the same IP, like servers and printers.

Question 36

What is dynamic IP addressing?

Answer 36

Dynamic IP (Automatic Setup) – The network gives the device an IP automatically (using something called DHCP), so you don’t have to do anything.

Question 37

IPv6

Answer 37

There aren’t enough IPv4 addresses for every device in the world, so we created IPv6. IPv4 uses 32-bit addresses (e.g., 192.168.1.1). IPv6 uses 128-bit addresses (which allows for way more devices to have unique addresses). Eventually, IPv6 will replace IPv4, but for now, they both exist together.

Question 38

What is Hexadecimal Notion?

Answer 38

Hexadecimal Notation: IPv6 addresses are written in hexadecimal (which uses numbers 0-9 and letters a-f). This is different from IPv4, which uses only numbers.

Question 39

What are nibbles?

Answer 39

Nibble: A single hex digit represents four binary bits (this little chunk of 4 bits is called a nibble).

Question 40

What is colon-separated format?

Answer 40

Colon-separated Format: Since an IPv6 address is 128 bits long, it’s split into eight groups of 16-bit values (called "double-byte" values), and they are separated by colons :. Example: 2001:0db8:0000:0000:0abc:0000:def0:1234 Shortening IPv6 Addresses: You can ignore leading zeros in any double-byte section. Example: 0abc becomes abc

Question 41

What is a continuous series of zeros?

Answer 41

A continuous series of zeros can be replaced with :: (this can only be done once in an address). Example: 2001:0db8:0000:0000:0abc:0000:def0:1234 becomes 2001:db8::abc:0:def0:1234

Question 42

IPv6 Network Prefixes

Answer 42

Two Main Parts: The first 64 bits are the network ID (like a ZIP code for your network). The last 64 bits are for a specific device/interface (like a house number). Prefix Notation (/nn): Instead of using a subnet mask like IPv4, IPv6 just says how many bits belong to the network. Example: 2001:db8::/64 means the first 64 bits are the network ID.

Question 43

What are Global addresses?

Answer 43

Works across the entire internet (like a public IPv4 address). Starts with 2 or 3.

Question 44

What are link-local addresses?

Answer 44

Only works inside a local network (like an internal IPv4 address). Always starts with fe80::.

Question 45

How Addresses Are Assigned?

Answer 45

IPv6 devices don’t always need manual setup. They can auto-assign themselves an address using a method called SLAAC (StateLess Address Auto Configuration).

Question 46

How IPv6 Finds Other Devices?

Answer 46

Instead of ARP (used in IPv4), IPv6 uses Neighbor Discovery (ND) to figure out who’s on the network.

Question 47

TCP

Answer 47

TCP (Transmission Control Protocol) Connection-Oriented: Sets up a connection before sending data (like starting a phone call). Reliable: Uses a handshake process to establish a connection (SYN → SYN/ACK → ACK). Every packet gets a sequence number so they arrive in order. If a packet is missing, the receiver asks for it again. Use Cases: Web browsing (HTTP/HTTPS): Every packet needs to arrive perfectly. SSH (Secure Shell): A single missing packet would ruin the connection.

Question 48

UDP

Answer 48

UDP (User Datagram Protocol) Connectionless: No handshake or setup. It just sends data (like texting without waiting for a reply). Faster but Less Reliable: No guarantee that packets arrive or that they arrive in order. Use Cases: Streaming (video, audio, gaming): A missing packet causes a small glitch, but the stream continues. DHCP (Dynamic Host Configuration Protocol): Used to get an IP address from a router—if the first request is lost, the client just tries again. TFTP (Trivial File Transfer Protocol): Used to load configurations for devices, and it has its own error-checking built in.

Question 49

Dynamic Host Configuration Protocol (DHCP)

Answer 49

Imagine you walk into a coffee shop, open your laptop, and connect to Wi-Fi. You didn’t type in an IP address—your laptop just got one automatically. That’s DHCP at work. Your computer needs an IP address (like a home address) to talk to other devices on the network or the internet. You could set this manually, but what if you mess up? You might pick an IP address that someone else is already using (like moving into a house where someone else already lives!). Instead, a DHCP server is like an automated landlord that hands out unique IP addresses to devices when they ask for one.

Question 50

DHCP Scope

Answer 50

The scope is the pool of IP addresses the DHCP server can give out. Think of it like a bucket of numbered tickets at a deli counter. If the numbers go from 192.168.0.100 to 192.168.0.199, that means there are 100 possible addresses available. Some addresses (like the router's own address, usually 192.168.0.1) are reserved and can’t be given out.

Question 51

DHCP Leases

Answer 51

When your device gets an IP address from the DHCP server, it doesn’t own it forever—it’s just "renting" it for a lease period. Here’s how that process works: 1. Your device yells out, "Hey, is there a DHCP server?" (this is a DHCPDISCOVER message). 2. The DHCP server responds, "Here, take this IP address!" (a DHCPOFFER). 3. Your device replies, "Okay, I’ll take it!" (a DHCPREQUEST). 4. The server confirms, "Alright, it's yours!" (a DHCPACK). 5. Your device quickly checks if someone else is using the IP by sending out a Who has this address? message (ARP request). If nobody answers, it starts using the IP. When the lease period is almost up, your device asks to renew it. If it can’t, it has to give up the address and ask for a new one.

Question 52

DHCP Reservations

Answer 52

Sometimes, you want a device to always have the same IP address—like a printer or a server. Instead of setting it manually (which is a hassle), the DHCP server can reserve an IP address for that device based on its MAC address (a unique hardware ID).

Question 53

Domain Name System (DNS)

Answer 53

Computers use IP addresses to find websites, but people aren’t great at remembering a bunch of numbers. So instead, we use domain names (like google.com), and DNS is the phonebook that translates those into IP addresses.

Question 54

How DNS Works

Answer 54

You type google.com into your browser. Your computer checks if it already knows the IP address. If not, it asks a DNS server, which responds with the correct IP address. Now your computer can contact Google’s servers using that IP. This happens super fast and is the reason you can browse the internet without memorizing numbers.

Question 55

Fully Qualified Domain Name (FQDN)

Answer 55

An FQDN is just the full version of a domain name. Example: nut.widget.example is an FQDN where: nut = the host (like a specific computer or server) widget = the company’s domain .example = the top-level domain (TLD, like .com or .org)

Question 56

DNS Record Types

Answer 56

DNS servers store different records to help route traffic: A Record → Maps a domain to an IPv4 address AAAA Record → Maps a domain to an IPv6 address CNAME Record → Aliases one domain to another (like www.example.com → example.com) MX Record → Handles email routing

Question 57

Virtual LANs (VLANs)

Answer 57

Imagine a giant office where everyone shares the same space and can hear each other’s conversations. That’s what happens when all computers in a network are in the same broadcast domain—lots of unnecessary "noise." A VLAN is like putting up walls and separating departments: One VLAN for HR One VLAN for Finance One VLAN for IT Each VLAN gets its own IP range and must go through a router to communicate with another VLAN. This helps with: ✅ Performance (less unnecessary traffic) ✅ Security (HR can’t see Finance's files) ✅ Prioritization (VoIP calls can be on a separate VLAN for better quality)

Question 58

Virtual Private Networks (VPNs)

Answer 58

Normally, when you’re outside your office and want to access work files, you can’t because you’re not physically connected to the company’s network. A VPN is like a secure tunnel through the internet that connects you to your work network as if you were there in person. It encrypts data so hackers can’t spy on it. It authenticates users to make sure only authorized people can connect. Once you’re connected, your computer acts like it's sitting inside the office, even if you’re at a coffee shop!