ccna module 11-13

What is an IPv4 address?

A 32-bit binary number used to identify devices on a network.

How is an IPv4 address typically written?

As 4 decimal numbers separated by dots (dotted-decimal notation). Example: 192.168.1.1

What are the two parts of an IPv4 address?

Network portion and Host portion.

What defines the separation between network and host portions?

The subnet mask.

What does a subnet mask do?

It identifies which part of the IP address is the network and which part is the host.

Example of a subnet mask in decimal?

255.255.255.0

What is the difference between private and public IP addresses?

Private IPs are used inside networks (not routable on the internet), public IPs are routable.

Example of a private IPv4 address range?

192.168.0.0 – 192.168.255.255

What address is reserved for all devices on a network?

Broadcast address (last address in a subnet).

What address refers to the current device?

Loopback address (127.0.0.1).

What is IPv6?

The successor to IPv4, designed to solve address exhaustion.

How many bits are in an IPv6 address?

128 bits.

How is an IPv6 address written?

As eight groups of four hexadecimal digits separated by colons.

Example IPv6 address?

2001:0db8:85a3:0000:0000:8a2e:0370:7334

What is "::" in IPv6?

A shorthand to compress multiple consecutive zeros.

What is the loopback address in IPv6?

::1

What is the IPv6 equivalent of private addresses?

Unique Local Addresses (ULA).

What type of IPv6 address starts with FE80?

Link-local address (used for communication on the same link).

Does IPv6 use NAT (Network Address Translation)?

No — it’s designed to have enough addresses for direct communication.

What is the main job of the Network Layer?

Determines how data is sent from one device to another across networks.

What are two main functions of the Network Layer?

Logical addressing and path selection (routing).

What protocol is responsible for addressing at the Network Layer?

IP (Internet Protocol).

What devices operate at the Network Layer?

Routers.

What is the difference between logical and physical addressing?

Logical = IP address; Physical = MAC address.

Why is the Network Layer necessary?

It allows data to travel between different networks (not just within the same one).

What is packet switching?

Breaking data into packets that are routed independently across the network.

What is fragmentation?

Splitting a large packet into smaller ones to fit the network’s size limits (MTU).

What is an MTU?

Maximum Transmission Unit: the largest packet size allowed by a link.

What happens if a packet is too big for the MTU?

It is fragmented into smaller packets at the Network Layer.