CCNA prep

Connects different IP networks

Router

Connects devices on a local network

Switch

Automatically provides IP configuration

DHCP

Logical network address

IP address

Link-layer hardware address

MAC address

How many layers are in the OSI model?

Seven layers

What are the seven OSI layers from 7 to 1?

Application, Presentation, Session, Transport, Network, Data Link, Physical

What does Layer 7 do?

Provides network services to applications. HTTP, DNS, SMTP

What does Layer 6 do?

Handles formatting, encryption, decryption, and compression

What does Layer 5 do?

Establishes, manages, and terminates communication sessions

What does Layer 4 do?

Provides end-to-end transport using TCP or UDP and port numbers

What does Layer 3 do?

Handles logical IP addressing and routing between networks

What does Layer 2 do?

Handles frames, MAC addressing, and local network delivery

What does Layer 1 do?

Transmits raw bits through physical media, signals, and cables

Which OSI layer uses IP addresses?

Layer 3 – Network

Which OSI layer uses MAC addresses?

Layer 2 – Data Link

Which OSI layer uses TCP and UDP?

Layer 4 – Transport

Which OSI layer uses port numbers?

Layer 4 – Transport

Which layer is associated with Ethernet cables and signals?

Layer 1 – Physical

Which layer does a traditional Ethernet switch primarily operate at?

Layer 2 – Data Link

Which layer does a router primarily operate at?

Layer 3 – Network

What is the PDU at Layer 4?

Segment (TCP) or datagram (UDP)

What is the PDU at Layer 3?

Packet

What is the PDU at Layer 2?

Frame.

What is the PDU at Layer 1?

Bits.

What is encapsulation?

Adding protocol information as data moves down the network layers.

What is decapsulation?

Removing protocol information as data moves up the network layers.

At which layer does DNS operate?

Layer 7 – Application

At which layer does ARP operate in the traditional OSI mapping?

Between Layers 2 and 3; resolves IPv4 addresses to MAC addresses on a local network.