CCNA Essentials

What does LAN stand for?

Local Area Network

What kind of network device is a Cisco 'Catalyst'?

Switch

What kind of network device is a Cisco ISR?

Router

____ firewalls are software applications that filter traffic entering and exiting a host machine, like a PC.

Host-based

What kind of network device is a Cisco ASA?

Firewall (ASA)

What kind of network device is a Cisco Firepower?

Firewall (Firepower)

A firewall which combines a traditional firewall with more advanced filtering functionalities is known as a '____ firewall'.

next-generation

Which organization defines standards used on local area networks?

IEEE (Institute of Electrical and Electronics Engineers)

Which organization defines standards used on the Internet?

IETF (Internet Engineering Task Force)

The IETF publishes standards in documents called ____.

RFCs (Requests for Comments)

In the 5-layer TCP/IP model, what is Layer 1?

Physical layer

In the 5-layer TCP/IP model, what is Layer 2?

Local Network layer (a.k.a., Data Link layer)

In the 5-layer TCP/IP model, what is Layer 3?

Internet layer (a.k.a., Network layer)

In the 5-layer TCP/IP model, what is Layer 4?

Transport layer

In the 5-layer TCP/IP model, what is Layer 5?

Application layer; *also called Layer 7 due to the OSI model

What is the name of the process in which headers and a trailer are added to a message before transmitting it?

Encapsulation

What is the name of the process in which headers and a trailer are removed from a message by the receiving host?

Decapsulation (or de-encapsulation)

What does PDU stand for?

protocol data unit

An L4PDU is called a ____ or ____

segment or datagram; (segment when using TCP, datagram when using UDP)

An L3PDU is called a ____.

packet

An L2PDU is called a ____.

frame

The contents of each PDU (everything encapsulated by that layer's header/trailer) are called the ____.

payload

The payload of a frame (L2PDU) is ____.

a packet (L3PDU)

The payload of a packet (L3PDU) is ____

a segment (TCP) or datagram (UDP) (L4PDU)

The payload of a segment or datagram (L4PDU) is ____

data (from the Application layer)

Interaction between a layer and those above and below it is called ____.

adjacent-layer interaction

Interaction between a layer and the equivalent layer on another device is called ____.

same-layer interaction

What two kinds of console ports are common on Cisco devices?

USB; RJ45

What kind of cable is used to connect to the RJ45 console port on a Cisco device?

Rollover cable

Default Cisco console port settings:; Speed (baud rate) = ____

9600 bits per second

Default Cisco console port settings:; Data bits = ____

8

Default Cisco console port settings:; Stop bits = ____

1 (stop bit)

Default Cisco console port settings:; Parity = ____

None (parity)

Default Cisco console port settings:; Flow control = ____

None (flow control)

In Cisco IOS, user EXEC mode is indicated by what?; Router____

>

In Cisco IOS, privileged EXEC mode is indicated by what?; Router____

#

In Cisco IOS, global configuration mode is indicated by what?; Router____

(config)#

View the available commands:; Router#____

?

Enter privileged EXEC mode:; Router>____

enable

Enter global configuration mode:; Router# ____

configure terminal

Configure an unencrypted password to protect privileged EXEC mode:; Router(config)# ____

enable password password

Return to privileged EXEC mode:; Router(config)# ____

exit

What two configuration files are kept on the device?

running-config, startup-config

View the running configuration:; Router# ____

show running-config

View the startup configuration:; Router# ____

show startup-config

Which three commands can be use to save the configuration?; Router# ____; Router# ____; Router# ____

write; write memory; copy running-config startup-config

Encrypt current and future passwords on the device:; Router(config)# ____

service password-encryption

Configure an MD5-encrypted enable password:; Router(config)# ____

enable secret password

You use the ____ keyword to execute privileged EXEC commands in global configuration mode.

do

Use the ____ keyword to remove a configured command.

no (for example, no service password-encryption)

Cisco's service password-encryption command uses type ____ encryption.

7 (password-encryption type)

enable secret uses type ____ (MD5) encryption.

5

If service password-encryption is removed, will currently encrypted passwords be decrypted?

No

What is the only field in an Ethernet trailer?

FCS (Frame Check Sequence)

What are the 5 fields of an Ethernet header?

Preamble, SFD, Destination, Source, Type/Length

What does 'SFD' in an Ethernet header stand for?

Start Frame Delimiter

What does 'FCS' in an Ethernet frame stand for?

Frame Check Sequence

Ethernet header 'Preamble' = […] byte(s)

7 (preamble bytes)

Ethernet header 'SFD' = […] byte(s)

1 (SFD byte)

Ethernet header 'Destination' = […] byte(s)

6 (destination bytes)

Ethernet header 'Source' = […] byte(s)

6 (source bytes)

Ethernet header 'Type/Length' = […] byte(s)

2

Ethernet trailer 'FCS' = […] byte(s)

4

Which field of an Ethernet header is used for synchronization?

Preamble

What is the bit pattern of one byte in the Ethernet preamble?

10101010

What is the bit pattern of the Ethernet SFD?

10101011

Which field of an Ethernet header marks the end of the preamble?

SFD

What does MAC stand for?

Media Access Control

How long is a MAC address? = […] bytes

6 (MAC address bytes)

How long is a MAC address? = […] bits

48

A value of […] or less in the Type/Length field indicates Length.

1500

A value of […] or greater in the Type/Length field indicates Type.

1536

What is the Ethernet Type value for IPv4? (in hexadecimal)

0x0800

What is the Ethernet Type value for IPv6? (in hexadecimal)

0x86DD

What kind of algorithm does the Ethernet FCS use?

CRC (Cyclic Redundancy Check)

What is another name for a MAC address?

BIA (Burned-In Address)

The first […] bytes of a MAC address are the OUI.

3

The first 3 bytes of a MAC address are the […]

OUI (Organizationally Unique Identifier)

A MAC address is written as […] hexadecimal characters.

12 (MAC hex characters)

Hexadecimal A = Decimal […]

10

Hexadecimal B = Decimal […]

11

Hexadecimal C = Decimal […]

12 (hex C)

Hexadecimal D = Decimal […]

13

Hexadecimal E = Decimal […]

14

Hexadecimal F = Decimal […]

15

A […] frame is a frame destined for a single target.

unicast

A MAC address learned by a switch without manual configuration is called a …

Dynamic MAC address (Dynamically learned MAC address)

What does a switch do with an unknown unicast frame?

Floods it out all ports (except the one it was received on)

By default, a dynamic MAC address will be removed from the MAC address table after [time] of inactivity.

5 minutes

Which field of an Ethernet frame does a switch use to learn and populate its MAC address table?

Source MAC Address

What is the size of the Ethernet header + trailer? (no Preamble + SFD)

18 bytes

What is the minimum size of an Ethernet frame? (Header + Payload + Trailer)

64 bytes

What is the minimum size of an Ethernet payload?

46 bytes

What protocol is used to discover the Layer 2 address of another device?

ARP (Address Resolution Protocol)

What two messages are used in ARP?

ARP RequestARP Reply

The ARP Request message is […]cast.

broad

The ARP Reply message is […]cast.

uni

What is the broadcast MAC address?

FFFF.FFFF.FFFF

What is the command to view the ARP table on a Windows, macOS, or Linux computer?

arp -a

What two messages are used in ping?

ICMP Echo RequestICMP Echo Reply