Networking: Network Layer

Question 1

Address class system

Answer 1

A system which defines how the global IP address space is split up

Question 2

Address Resolution Protocol (ARP)

Answer 2

A protocol used to discover the hardware address of a node with a certain IP address

Question 3

ARP table

Answer 3

A list of IP addresses and the MAC addresses associated with them

Question 4

ASN

Answer 4

Autonomous System Number is a number assigned to an individual autonomous system

Question 5

Demarcate

Answer 5

To set the boundaries of something

Question 6

Demarcation point

Answer 6

Where one network or system ends and another one begins

Question 7

Destination network

Answer 7

The column in a routing table that contains a row for each network that the router knows about

Question 8

DHCP

Answer 8

A technology that assigns an IP address automatically to a new device. It is an application layer protocol that automates the configuration process of hosts on a network

Question 9

Dotted decimal notation

Answer 9

A format of using dots to separate numbers in a string, such as in an IP address

Question 10

Dynamic IP address

Answer 10

An IP address assigned automatically to a new device through a technology known as Dynamic Host Configuration Protocol

Question 11

Exterior gateway

Answer 11

Protocols that are used for the exchange of information between independent autonomous systems

Question 12

Flag field

Answer 12

It is used to indicate if a datagram is allowed to be fragmented, or to indicate that the datagram has already been fragmented

Question 13

Fragmentation

Answer 13

The process of taking a single IP datagram and splitting it up into several smaller datagrams

Question 14

Fragmentation offset field

Answer 14

It contains values used by the receiving end to take all the parts of a fragmented packet and put them back together in the correct order

Question 15

Header checksum field

Answer 15

A checksum of the contents of the entire IP datagram header

Question 16

Header length field

Answer 16

A four bit field that declares how long the entire header is. It is almost always 20 bytes in length when dealing with IPv4

Question 17

IANA

Answer 17

The Internet Assigned Numbers Authority, is a non-profit organization that helps manage things like IP address allocation

Question 18

Identification field

Answer 18

It is a 16-bit number that’s used to group messages together

Question 19

Interface

Answer 19

For a router, the port where a router connects to a network. A router gives and receives data through its interfaces. These are also used as part of the routing table

Question 20

Interior gateway

Answer 20

Interior gateway protocols are used by routers to share information within a single autonomous system

Question 21

IP datagram

Answer 21

A highly structured series of fields that are strictly defined

Question 22

IP options field

Answer 22

An optional field and is used to set special characteristics for datagrams primarily used for testing purposes

Question 23

Network Address Translation (NAT)

Answer 23

A mitigation tool that lets organizations use one public IP address and many private IP addresses within the network

Question 24

Next hop

Answer 24

The IP address of the next router that should receive data intended for the destination networking question or this could just state the network is directly connected and that there aren’t any additional hops needed. Defined as part of the routing table

Question 25

Non-routable address space

Answer 25

They are ranges of IPs set aside for use by anyone that cannot be routed to

Question 26

Padding field

Answer 26

A series of zeros used to ensure the header is the correct total size

Question 27

Protocol field

Answer 27

A protocol field is an 8-bit field that contains data about what transport layer protocol is being used

Question 28

Routing protocols

Answer 28

Special protocols the routers use to speak to each other in order to share what information they might have

Question 29

Service type field

Answer 29

A eight bit field that can be used to specify details about quality of service or QoS technologies

Question 30

Static IP address

Answer 30

An IP address that must be manually configured on a node

Question 31

Subnet mask

Answer 31

32-bit numbers that are normally written as four octets of decimal numbers

Question 32

Subnetting

Answer 32

The process of taking a large network and splitting it up into many individual smaller sub networks or subnets

Question 33

Time-To-Live field (TTL)

Answer 33

An 8-bit field that indicates how many router hops a datagram can traverse before it's thrown away

Question 34

Total hops

Answer 34

The total number of devices data passes through to get from its source to its destination. Routers try to choose the shortest path, so fewest hops possible. The routing table is used to keep track of this

Question 35

Total length field

Answer 35

A 16-bit field that indicates the total length of the IP datagram it's attached to