|
Tests with answers
|
Sana | 09.02.2022 | Hajmi | 20.44 Kb. | | #17297 |
Bog'liq Computer Networks
Tests with answers
The Internet Control Message Protocol (ICMP) allows
Answer: The exchange of error messages among routers and hosts
Layered protocol architectures
Answer: are widely used because they ensure scalability and simplicity
The SMTP Protocol
Answer: is used for the delivery of outgoing electronic mail messages from a client to server
In a stop & wait AR protocol
Answer: a device can send only one packet and then it has to stop, waiting for an acknowledge
In a Sliding Window transmission protocol (e.g., Go-Back-N)
Answer: a device can send out an arbitrary number of packets without waiting for acknowledge
A possible IP network that can be assigned to an Ethernet network containing 200 nodes is
Answer: 130.192.2.0/24
Two IP nodes 130.192.40.1/24 e 130.192.40.200/24
Answer: can directly exchange IP packets
In the CSMA/CD protocol, a station completes the transmission of a frame
Answer: only if, sensing the channel, it doesn’t detect an eventual simultaneous reception with the current transmission
Congestion control in TCP
Answer: limits the size of the transmission window
The Internet network
Answer: is based on packet switching
In a packet switched network, the routing is
Answer: the process use for determining the source-destination routes taken by packets, i.e., for writing the routing table
The IP protocol provides a service that is
Answer: unreliable (i.e., without any delivery guarantee) and connectionless
End-to-end error recovery over the Internet, when available
Answer: is implemented at the Transport Layer.
The IP header, i.e., the IP PCI, mandatorily contains
Answer: The Time To Live (TTL) field that enables removing from the network packets that were forwarded by too many routers / the code field, …tcp
During the slow-start phase of the TCP congestion control, the transmission window size of the sender
Answer: grows of one segment at every received acknowledgement
The flow control in the TCP protocol
Answer: is based on some information included into the segments sent from the receiver to the sender
The end-to-end delay in a computer network
Answer: depends on the network load
An Ethernet Switch, when it receives an ARP request packet
Answer: forwards it on all ports, except the one over which the packet has been received
A DHCP server deployed in a local area network provides
Answer: an IP configuration to hosts connected to the local area network
The which access network separates data and phone calls on the same transmission media between the user equipments and the ISP equipments
Answer: frequency division multiplexing
A network protocol is
Answer: a set of rules that devices must user for communications
Which among the followings is a distinctive function of the Link in a networking layered architecture?
Answer: delivery of packets (referred to as frames at this layer) among neighboring nodes
The congestion control for the Transmission Control Protocol (TCP) is based
Answer: on the adjustment of the transmission window size according to the memory availability at the receiver
The POP3 Protocol
Answer: can be used to transfer electronic mail messages from a server to client installed on a PC
The PING program is
Answer: based on Echo Request and Echo Reeply ICMP messages
The class C IPv4 addresses distinguish:
Answer: (a few) networks with a large number of hosts
TCP dynamically changes the transmission window size to obtain
Answer: only flow control
The introduction of subnet masks in the Internet addressing
Answer: enables the utilization of a single logical IP network over more than one physical network
TCP segments
Answer: have a variable size that is selected on the basis of the congestion level in the network
The Address Resolution Protocol (ARP)
Answer: disallows a host to obtain an IP address
Answer: achieves a translation function between layer-3 addresses and layer-2 addresses
The header of a data packet in a packed switching network with datagram service includes
Answer: the addresses of the source and destination nodes
The throughput (i.e., the amount of transferred bits per second) offered to a traffic flow
Answer: is given by the lowest throughput offered in all the traversed links, i.e., the bottleneck
The packet switching technology
Answer: Ensures efficient bandwidth utilization
An Ethernet swich is
Answer: a network node that forwards frame on the basis of MAC address
In a routing table, the next-hop column of a static route is
Answer: the IP address of a remote interface directly connected to the router
The Network Layer of the Internet protocol stack
Answer: Is based on the IP protocol
Transport layer of the internet protocol stack
Answer: Might open connections before sending data
The core of the Internet network
Answer: is a network based on mesh of interconnected switches
The Ethernet technology
Answer: is based on CSMA/CD protocol
The HTTP protocol
Answer: uses one or more TCP connections
A client operating according to the selective-respect protocol (based on packets)
Answer: retransmits only the packet that caused the timer expiration
The Network Layer
Answer: is over the Link Layer and below the Transport Layer
The Ethernet technology
Answer: can be based on switches in order to obtain better performance
44. After having identified the correct output port, an IP router
Answer: modifies the Time To Live and Header Checksum field of the datagram header
If a router receives an IP packet with correct checksum ,TTL=9 , and equal IP sourse and IP destination addresses
Answer: it forwards the packet to the destination
Let’s consider a host who is transmitting data by means of TCP .Give a current value for the transmission window size equal to 10 segments , with a maximum receive window equal to 40 segments, when the sender receives a segment containing an acknowledgment from the receiver , which to the following situations is impossible?
Answer: the current value of the transmission window size becomes equal to 51 segments
The IP version 4 addresses are:
Answer: of fixed total length, but consisting of a variable length part identifying the network and a variable length part identifying the host
The destination IP address in an IP packet is
Answer: a fundamental header field, used by routers to forward the packet
The header of a data packet in a packed switching network with datagram service includes
Answer: the addresses of the source and destination nodes
During the slow-start phase of the TCP congestion control, the transmission window size of the sender
Answer: doubles at every received acknowledgement
The DSL access network separates data and phone calls on the same transmission media between the user equipments and the ISP equipments using
Answer: frequency division multiplexing
Which of the following claims is false?
Answer: A host transmits IP packets only to hosts whose net_id is equal to its own net_id.
|
| |