WEB |COMPLETE STUDY GUIDE WITH 100% ACCURATE
QUESTIONS & ANSWERS | ACE EVERY TEST |
GUARANTEED EXCELLENCE.
What ICMP is used for Answer: 1. Error reporting
For example:
Destination unreachable The packet cannot get to the target.
Time exceeded The packet took too many hops and was destroyed.
Fragmentation needed The packet is too large to pass through a link.
2. Network diagnostics
The most famous examples are:
ping
traceroute
Ping
Ping uses ICMP to check whether another device is reachable.
It sends:
ICMP Echo Request
and gets back:
ICMP Echo Reply
So ping is basically asking:
"Are you there?"
and the other host answers:
"Yes, I'm here."
Ping Answer: Ping uses ICMP to check whether another device is reachable.
It sends:
ICMP Echo Request
and gets back:
ICMP Echo Reply
APPHIA – Crafted with Care and Precision for Academic Excellence.
1
,So ping is basically asking:
"Are you there?"
and the other host answers:
"Yes, I'm here."
Traceroute Answer: Traceroute uses ICMP or sometimes UDP, depending on the system.
It finds the path packets take across routers.
It works by making packets expire on purpose, and routers send back ICMP Time Exceeded
messages.
That is how traceroute discovers each router on the path.
MAC address: Answer: A MAC address is a unique identifier given to a network
device/interface.
It is mainly used for communication on a local network like your home Wi-Fi or a university
LAN.
Packet: Answer: Header
Data
Header Answer: source IP address
destination IP address
TTL
protocol
fragmentation information
header length
Segmentation: Answer: done by the transport layer
creates segments
usually done by TCP
based on transporting application data
Fragmentation: Answer: done by the network layer
creates fragments
done by IP
APPHIA – Crafted with Care and Precision for Academic Excellence.
2
, based on fitting packet size to the MTU
UDP: Answer: -> User Datagram Protocol
A datagram is just an independent message.packet
->UDP is connectionless meaning it does not first build a formal connection before sending
data
reliability in TCP Answer: 1- Sequence numbers
2- ACknowledgements
3- Retransmissions
4- Reordering
Flow Control Answer: ->receive window:
The receiver tells the sender how much space it currently has available
Congestion Control: Answer: prottects the network
URIS Answer: URI
Uniform Resource Identifier This is the broadest category.
URL
Uniform Resource Locator This tells you where or how to access something.
Example:
https://example.com/page.html
URN
Uniform Resource Name This gives something a name/identity, not necessarily a location
Proxy: Answer: ->A proxy receives a request and forwards it on behalf of someone else
-> It acts like a representative
->
Gatway: Answer: ->It is more like a bridge or a translator:
Example
Suppose one system speaks one protocol and another system speaks another protocol.
The gateway may:
receive one type of request
APPHIA – Crafted with Care and Precision for Academic Excellence.
3
QUESTIONS & ANSWERS | ACE EVERY TEST |
GUARANTEED EXCELLENCE.
What ICMP is used for Answer: 1. Error reporting
For example:
Destination unreachable The packet cannot get to the target.
Time exceeded The packet took too many hops and was destroyed.
Fragmentation needed The packet is too large to pass through a link.
2. Network diagnostics
The most famous examples are:
ping
traceroute
Ping
Ping uses ICMP to check whether another device is reachable.
It sends:
ICMP Echo Request
and gets back:
ICMP Echo Reply
So ping is basically asking:
"Are you there?"
and the other host answers:
"Yes, I'm here."
Ping Answer: Ping uses ICMP to check whether another device is reachable.
It sends:
ICMP Echo Request
and gets back:
ICMP Echo Reply
APPHIA – Crafted with Care and Precision for Academic Excellence.
1
,So ping is basically asking:
"Are you there?"
and the other host answers:
"Yes, I'm here."
Traceroute Answer: Traceroute uses ICMP or sometimes UDP, depending on the system.
It finds the path packets take across routers.
It works by making packets expire on purpose, and routers send back ICMP Time Exceeded
messages.
That is how traceroute discovers each router on the path.
MAC address: Answer: A MAC address is a unique identifier given to a network
device/interface.
It is mainly used for communication on a local network like your home Wi-Fi or a university
LAN.
Packet: Answer: Header
Data
Header Answer: source IP address
destination IP address
TTL
protocol
fragmentation information
header length
Segmentation: Answer: done by the transport layer
creates segments
usually done by TCP
based on transporting application data
Fragmentation: Answer: done by the network layer
creates fragments
done by IP
APPHIA – Crafted with Care and Precision for Academic Excellence.
2
, based on fitting packet size to the MTU
UDP: Answer: -> User Datagram Protocol
A datagram is just an independent message.packet
->UDP is connectionless meaning it does not first build a formal connection before sending
data
reliability in TCP Answer: 1- Sequence numbers
2- ACknowledgements
3- Retransmissions
4- Reordering
Flow Control Answer: ->receive window:
The receiver tells the sender how much space it currently has available
Congestion Control: Answer: prottects the network
URIS Answer: URI
Uniform Resource Identifier This is the broadest category.
URL
Uniform Resource Locator This tells you where or how to access something.
Example:
https://example.com/page.html
URN
Uniform Resource Name This gives something a name/identity, not necessarily a location
Proxy: Answer: ->A proxy receives a request and forwards it on behalf of someone else
-> It acts like a representative
->
Gatway: Answer: ->It is more like a bridge or a translator:
Example
Suppose one system speaks one protocol and another system speaks another protocol.
The gateway may:
receive one type of request
APPHIA – Crafted with Care and Precision for Academic Excellence.
3
