Quizz in networks architecture Please answer each question with clear explaination. Don't do questions with figures Assuming there is no NAT in the network, which two statements about MAC and IP addresses during data transmission are correct? $($Choose two.$)$

Destination IP addresses in a packet header remain constant throughout the path to a target machine.

Destination MAC addresses will never change in a frame that passes through different routers.

Each time a frame is encapsulated with a new destination MAC address, a new destination IP address is required.

Destination and source MAC addresses have a local meaning and change each time a frame passes from one physical network to another.

A packet that has passed through four routers has changed its destination IP address four times.

What is the main characteristic of the data link layer? $-$

It generates the electrical signals, which represent the data, on the medium.

It converts a stream of data bits into a predefined code.

It delivers the data to the destination in the same physical network.

It accepts layer $3$ packets and decides which path to take to transmit the packet to a remote network.

What are the three characteristics of the CSMA$/$CD method?

The equipment with the token is the only one that can transmit after a collision.

A device listens and waits until the media is not busy before transmitting. After detecting a collision, the machines can attempt to resume transmission after a random delay has expired.

Devices can be configured with a higher transmission priority.

What are the two main responsibilities of the Ethernet MAC sublayer? $($Choose two.$)$

data routing

media access

identifying destinations in the same network

logical addressing

Which command can be used on a Linux machine to display the routing table?

tcpdump

route

ifconfig

arp

What are the two functions performed by the network layer?

routing data packets to destination machines on other networks transmitting data over the network medium

transporting data between applications operating on source and destination machines

providing dedicated end$-$to$-$end connections

providing end devices with a logical identifier

A user sends a request to a server on a remote network. When encapsulating this request, what information is added to the address field of the ethernet frame to indicate the destination?

the network domain of the destination machine

the IP address of the default gateway

the MAC address of the destination machine

the MAC address of the default gateway

Refer to the figure. Machine A needs to communicate with machine D$,$ but it does not have the MAC address of the default gateway. Which machines will receive the ARP request sent by machine A$?$

only machine D

only router R$1$

only machines A$,$ B and C

only machines A$,$ B$,$ C and D

only machines B and C

only machines B$,$ C and router R$1$

Which of the following are properties of a switch?

It is a level $1$ device

It sends information to the right destination according to the destination MAC address.

It divides the network into different collision domains

It broadcasts the data received on all ports.

Which of the following information is checked by TCP each time a message is received in a connection?

connection? $($choose $3)$

sequence number

reception window size

type of coding used

IP address

Port number

A $10-$metre cable is used with a propagation speed of $300,000$ km$/$s$.$ The transmission

is $100$ Mbit$/$s$.$ What is the propagation time $($PT$)$ on the cable and the time.

to transmit a $96-$byte frame $($ET$).$

PT $=100$x$10^-6,$ ET$448$x$10^-4$

PT $=33$x$10^-6,$ ET $384$x$10^-8$

$-$

PT$=68$x$10^-6,$ SD $=340$x$10^-5$

We have a network address $192\mathrm{.}168\mathrm{.}0\mathrm{.}0/24,$ we need to give an addressing plan for $5$

subnets, subnet $1$: $39$ machines, subnet $2$: $48$ machines, subnet $3$: $12$

machines, subnetwork $4$: $9$ machines, subnetwork $5$: $2$ machines. Which of the following plans is

correct?

subnet $1$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}0/27,$ subnet $2$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}64/27,$ subnet $3$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}130/28,$

subnet $4$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}160/29,$ subnet $5$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}180/28$

subnet $1$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}0/26,$ subnet $2$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}128/27,$ subnet $3$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}162/27,$

subnet $4$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}192/28,$ subnet $5$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}240/30$

subnet $1$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}0/26,$ subnet $2$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}64/26,$ subnet $3$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}128/28,$

subnet $4$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}160/28,$ subnet $5$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}176/30$