384 Study Guide Exam 1

Layer 1

Physical

Layer 2

Data Link

Layer 3

Network

Layer 4

Transport

Layer 5

Application

Unit of Communication Layer 1

Bits

Unit of Communication Layer 2

Frames

Unit of Communication Layer 3

Packets (IPv4 or IPv6)

Unit of Communication Layer 4

TCP Segments or UDP Datagrams

Unit of Communication Layer 5

Data

Addressing Layer 2

MAC addresses

Addressing Layer 3

IP addresses

Addressing Layer 4

Port numbers

Delivery Type Layer 2

Local

Delivery Type Layer 3

Indirect

Delivery Type Layer 4

End-to-end

Encapsulation

adding the header as data moves down the layers.

Decapsulation

removing the header as data moves up the layers.

Command to Set Root User

sudo -i or su -

Command to Edit Files

nano or vi

Command to Check Network Interfaces

ip a

Layer 2 Main Protocol

Ethernet

Frame Field Preamble

Synchronization

Frame Field Destination MAC

Identifies recipient

Frame Field Source MAC

Identifies sender

Frame Field Type/Length

Protocol type or data size

Frame Field Payload

Data being transferred

Frame Field FCS

Error checking

Frame Size Min Length

64 bytes

Frame Size Max Length

1518 bytes

Frame Data Length

Up to 1500 bytes

Unicast

Single device communication

Multicast

communication with a group of devices

Broadcast

All devices on the network (all f’s)

Padding

Ensures frame meets minimum size

Layer 3 Main Protocol

IP

Layer 3 Services

Routing, Logical addressing, Packet forwarding

Datagram Header Field Version

IPv4 or IPv6

Datagram Header Field Header Length

Size of the header

Datagram Header Field Source Address

Sender's IP address

Datagram Header Field Destination Address

Recipient's IP address

Datagram Header Field TTL

Limits packet's lifetime - The field that limits the lifetime of a packet to avoid loops.

Datagram Header Length Min

20 bytes

Datagram Header Length Max

60 bytes

Purpose of Fragmentation

Breaks large packets into smaller for easy transportation