EXAM ALL QUIZ/MIDTERM
QUESTIONS WITH ACCURATE
ANSWERS
T/F: Before sending a packet into the internet, the source must determine all of the links
that packet will traverse between source and destination. - ANSWERSFalse
T/F: Layers four and five of the Internet protocol stack are implemented in the end
systems but not in the routers in the network core. - ANSWERSTrue, Layers 4 and 5
are the Application and Transport layers
T/F: The Internet provides its applications two types of services, a TDM (Time Division
Multiplexing) service and a FDM (Frequency Division Multiplexing) service. -
ANSWERSFALSE. Packet Switching is the now modern used service.
T/F: Suppose 10 connections traverse the same link of rate 1 Gbps. Suppose that the
client access links all have rate 5 Mbps. Then the maximum throughput for each
connection is 100 Mbps. - ANSWERSFalse! Maximum throughput is limited to the
smallest pipe, i.e. 5 Mbps.
T/F: Consider a queue preceding a transmission link of rate R. Suppose a packet
arrives to the queue periodically every 1/a seconds. Also suppose all packets are of
length L. Then the queuing delay is small and bounded as long as aL < R. -
ANSWERSTrue! R is bits or bytes per second, so if a packet is L bits/bytes long, and it
passing the transmission link at rate 1/a seconds...
T/F: In a virtual-circuit packet-switched network, a packet switch maintains state
information for each connection passing through the router. - ANSWERSTrue!
Parts that make up network delay. - ANSWERSQueuing Delay -
Transmission Delay-
Processing Delay-
Propagation Delay-
Ethernet runs on what media: - ANSWERSFiber
Co-axial cables
Unshielded twisted pair (UTP)
Processes running on different hosts communicate using: - ANSWERSMessages
, Process running on a host machine is identified by: - ANSWERShost IP address and
the associated port number
TCP Service Provides: - ANSWERSReliable Transport, Flow Control, Connection
oriented, Congestion contol
UDP service: - ANSWERSUnreliable, used in gaming applications
What is true for HTTP: - ANSWERSIt can be both non-persistent and persistent, it uses
tcp, and is stateless.
HTTP 1.0 protocol supports following methods: - ANSWERSGET, HEAD, POST
T/F: Connections in a UDP application starts with a 3-way handshake -
ANSWERSFALSE! UDP is the sending of information with no handshake to a
destination. This is why it is unreliable.
3-Way handshake has the following paket sequence: - ANSWERS1. SYN,
2. SYN-ACK,
3. ACK
Assuming a single non-persistent connection, how long does it take to to download a
very small object from a server?
What about 3 very small objects? - ANSWERS1 object: 2 RTT (Round trip time)
3 objects: 6 RTT
Which DNS record gives the IP of a host? - ANSWERS'A'
T/F: Consider an HTTP Web server using persistent connections. Suppose the server
spawns a separate process for each client that connects to the server. Then each of
these spawned processes will have different server port numbers. - ANSWERSFalse!
The server uses the client side ip and port to determine what to respond to and where to
send a response.
T/F: Suppose that host A wants to send data over TCP to host B, and host B wants to
send data to host A over TCP. Two separate TCP connections - one for each direction -
are needed. - ANSWERSFalse! Once a three way handshake is established, data can
be transmitted in both directions.
A HTTP server has two types of sockets. Name and describe them. -
ANSWERSPassive socket is one that is set up and is just listening for connections, and
will establish one when found.
Active socket is one that actually does data transfer.
What is the TCP/UDP checksum of the following two numbers