IPv4 Addressing and Protocol

Why are MAC addresses not sufficient for networking?

They do not contain network location information.

Why can't MAC addresses be used across networks?

They only work on local networks (Layer 2 scope).

What protocol allows communication between networks?

Internet Protocol (IP).

What layer does IP operate on?

Layer 3 (Network layer).

What is the PDU (Protocol Data Unit) of Layer 3?

Packet.

What does IP define?

Rules for Layer 3 communication, addressing, and packet handling.

What are the two types of IP addressing?

Classful and subnetted.

What is classful addressing?

Uses default network masks.

What is subnetted addressing?

Uses modified subnet masks.

What type of delivery does IP provide?

Connectionless delivery.

What does connectionless mean?

Each packet is independent and no session is established.

Is IP reliable?

No, it is unreliable (no delivery guarantee).

What is best-effort delivery?

Packets are delivered if possible, otherwise dropped.

What is fragmentation?

Breaking packets into smaller pieces for transmission.

Why is fragmentation needed?

Because IP packets may be larger than network MTU.

What field identifies packet fragments?

Identification field.

What field controls fragmentation?

Flags field.

What does the "Do Not Fragment" flag do?

Prevents fragmentation.

What does the "More Fragments" flag indicate?

More fragments follow.

What is fragment offset?

Indicates position of fragment in original packet.

What is TTL?

Time To Live (hop count).

What happens when TTL reaches 0?

The packet is dropped.

What does the Protocol field indicate?

The next layer protocol (TCP, UDP, etc.).

What does the checksum field do?

Detects errors in the IP header.

What is the TOS field?

Defines packet priority (QoS).

What TOS value has highest priority?

7 (Network Control).

What is a unicast address?

One-to-one communication.

What is a multicast address?

One-to-many group communication.

What is the multicast address range?

224.0.0.0 to 239.255.255.255.

What organization assigns multicast ranges?

IANA.

What is a broadcast address?

An address used to send to all devices.

What is a limited broadcast address?

255.255.255.255.

What is a directed broadcast?

Broadcast to a specific network.

What is the loopback address?

127.0.0.1.

What is loopback used for?

Testing the local system.

What is APIPA?

Automatic Private IP Addressing.

What is the APIPA range?

169.254.0.1 to 169.254.255.254.

When is APIPA used?

When DHCP fails.

What are private IP ranges?

Reserved IPs for internal networks.

What is NAT used for?

Translating private IPs to public IPs.

What is a broadcast domain?

All devices that receive a broadcast.