Computer Network Questions and Answers

Answer: C

The APIPA range is 169.254.0.1 to 169.254.255.254.

Automatic Private IP Addressing lets a Windows computer that cannot reach a DHCP server assign itself an address from the link-local block 169.254.0.0/16, with subnet mask 255.255.0.0. Usable host addresses run from 169.254.0.1 to 169.254.255.254.

The ranges ending in 169.254.0.254 or 169.254.0.255 cover only a /24 block, and 169.254.255.255 is the broadcast address of the block, which cannot be assigned to a host.

Answer: D

The answer is All of the above.

IP is a best-effort, connectionless protocol. It does not acknowledge delivery, retransmit, sequence or check for duplicates, so packets may be lost, may take different routes and arrive out of order, and may be duplicated in the network.

Each of the first three options names one of these failures, so none of them alone is the full reason. Reliability is left to higher layers such as TCP.

Answer: D

The source and destination addresses are 32 bits each.

In the IPv4 header, the source address and destination address fields are each 32 bits (4 bytes), written in dotted decimal as four 8-bit numbers, such as 192.168.1.1.

4 bits is the size of the version and header length fields, 8 bits that of the time-to-live and protocol fields, and 16 bits that of the total length and checksum fields. (IPv6 addresses are 128 bits.)

Answer: B

UDP stands for User Datagram Protocol.

UDP is a transport layer protocol of the Internet protocol suite. It sends independent packets (datagrams) without setting up a connection, without acknowledgements and without guaranteed delivery, which makes it fast and suitable for streaming, DNS lookups and online games.

'Program' and 'Utility Development Program' are not what the P stands for, and 'User Defined Protocol' replaces 'Datagram', the word that describes how UDP sends data.

Answer: D

The answer is Reliability.

UDP is a connectionless transport protocol. It sends datagrams without setting up a connection, without acknowledgements and without retransmission, so it does not provide reliable delivery; applications that need reliability must add it themselves or use TCP.

The other three are applications that commonly run over UDP: the Network File System (in its traditional versions), the Domain Name System for ordinary queries, and the Simple Network Management Protocol.

Answer: C

The protocol is TELNET.

TELNET (teletype network) is a client-server protocol that lets a user log in to a remote computer over a network, so that the local terminal behaves as if it were a terminal attached directly to the remote system. It traditionally uses TCP port 23 and sends data unencrypted, which is why SSH has largely replaced it.

SMTP transfers e-mail between servers, FTP transfers files between computers, and DNS translates domain names into IP addresses. None of them provides an interactive remote terminal session.

Answer: D

LTE provides a peak downlink data rate of more than 100 Mbps.

Long Term Evolution, the 4G standard developed by 3GPP, was designed with a target peak downlink rate of at least 100 Mbps in a 20 MHz channel, and with multiple-antenna (MIMO) configurations its specified peak rates go well beyond that, to around 300 Mbps in early releases. Uplink peaks are lower, around 50 to 75 Mbps.

'Less than 50 Mbps' and 'less than 100 Mbps' describe 3G-era speeds, while rates above 1 Gbps belong to LTE-Advanced and 5G rather than to LTE itself.

Answer: B

The unique network address is the Internet Protocol Address.

Every device connected to the Internet is identified by an IP address, either IPv4 (such as 192.168.1.1) or IPv6, which lets data packets be routed to it across networks.

A MAC address is a hardware address burnt into a network card and used only within a local network. A port number identifies a particular service or application on a device, not the device itself, and 'specific address' is not a technical term.

Answer: D

Data translation and encryption are handled by the presentation layer.

The presentation layer, layer 6 of the seven-layer OSI model, translates data between the application's format and the network format, and handles encryption, decryption and compression.

The transport layer (4) provides end-to-end delivery and error recovery, the network layer (3) handles routing and logical addressing, and the data link layer (2) handles framing and physical addressing.

Answer: C

IPv6 defines an IP address of 128 bit.

IPv6 addresses are 128 bits long, usually written as eight groups of four hexadecimal digits, which allows about 3.4 × 10³⁸ addresses. IPv6 was introduced because the 32-bit addresses of IPv4, about 4.3 billion of them, were running out.

32 bits is the size of an IPv4 address. 64 bits is the size of the interface identifier in a typical IPv6 address, half the address, and 256 bits is not used.