Q. Suppose two hosts use a TCP connection to transfer a large file. Which of the following statements is/are False with respect to the TCP connection?

1. If the sequence number of a segment is m, then the sequence
number of the subsequent segment is always m+1.
2. If the estimated round trip time at any given point of time
is t sec, the value of the retransmission timeout is always
set to greater than or equal to t sec.
3. The size of the advertised window never changes during the
course of the TCP connection.
4. The number of unacknowledged bytes at the sender is always
less than or equal to the advertised window

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Q. A link has a transmission speed of 10^6 bits/sec. It uses data packets of size 1000 bytes each. Assume that the acknowledgment has negligible transmission delay, and that its propagation delay is the same as the data propagation delay. Also assume that the processing delays at nodes are negligible. The efficiency of the stop-and-wait protocol in this setup is exactly 25%. The value of the one-way propagation delay (in milliseconds) is ___________.

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Q. Identify the correct order in which a server process must invoke the function calls accept, bind, listen, and recv according to UNIX socket API.

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Q. Assume that the bandwidth for a TCP connection is 1048560 bits/sec. Let α be the value of RTT in milliseconds (rounded off to the nearest integer) after which the TCP window scale option is needed. Let β be the maximum possible window size with window scale option. Then the values of α and β are

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Q. Consider the following statements.

I. TCP connections are full duplex.
II. TCP has no option for selective acknowledgment
III. TCP connections are message streams.

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Q. Consider a network connecting two systems located 8000 kilometers apart. The bandwidth of the network is 500 × 10^6 bits per second. The propagation speed of the media is 4 × 10^6 meters per second. It is needed to design a Go-Back-N sliding window protocol for this network. The average packet size is 10^7 bits. The network is to be used to its full capacity. Assume that processing delays at nodes are negligible. Then, the minimum size in bits of he sequence number field has to be ________.

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Q. On a TCP connection, current congestion window size is Congestion Window = 4 KB. The window size advertised by the receiver is Advertise Window = 6 KB. The last byte sent by the sender is LastByteSent = 10240 and the last byte acknowledged by the receiver is LastByteAcked = 8192. The current window size at the sender is  

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Q. For a host machine that uses the token bucket algorithm for congestion control, the token bucket has a capacity of 1 megabyte and the maximum output rate is 20 megabytes per second. Tokens arrive at a rate to sustain output at a rate of 10 megabytes per second. The token bucket is currently full and the machine needs to send 12 megabytes of data. The minimum time required to transmit the data is _________________ seconds.

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Q. Consider the following statements about the timeout value used in TCP. i. The timeout value is set to the RTT (Round Trip Time) measured during TCP connection establishment for the entire duration of the connection. ii. Appropriate RTT estimation algorithm is used to set the timeout value of a TCP connection. iii. Timeout value is set to twice the propagation delay from the sender to the receiver. Which of the following choices hold?

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Q. Consider a TCP connection in a state where there are no outstanding ACKs. The sender sends two segments back to back. The sequence numbers of the first and second segments are 230 and 290 respectively. The first segment was lost, but the second segment was received correctly by the receiver. Let X be the amount of data carried in the first segment (in bytes), and Y be the ACK number sent by the receiver. The values of X and Y (in that order) are

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Q. Which of the following statements are TRUE?

(S1) TCP handles both congestion and flow control
(S2) UDP handles congestion but not flow control
(S3) Fast retransmit deals with congestion but not flow control
(S4) Slow start mechanism deals with both congestion and flow control

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Q. Consider different activities related to email.

m1: Send an email from a mail client to a mail server
m2: Download an email from mailbox server to a mail client
m3: Checking email in a web browser

Which is the application level protocol used in each activity?

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Q. Identify the correct order in which the following actions take place in an interaction between a web browser and a web server.

1. The web browser requests a webpage using HTTP.
2. The web browser establishes a TCP connection
with the web server.
3. The web server sends the requested webpage
using HTTP.
4. The web browser resolves the domain name
using DNS.

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Q. A graphical HTML browser resident at a network client machine Q accesses a static HTML webpage from a HTTP server S. The static HTML page has exactly one static embedded image which is also at S. Assuming no caching, which one of the following is correct about the HTML webpage loading (including the embedded image)?

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Q. Consider the following statements: I. telnet, ftp and http are application layer protocols. II.l EJB (Enterprise Java Beans) components can be deployed in a J2EE (Java2 Enterprise Edition) application server. III. If two languages conform to the Common Language Specification (CLS) of the Microsoft.NET framework, then a class defined in any one of them may be inherited in the other. Which statements are true?

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Q. Which of the following is/are example(s) of stateful application layer protocols?

(i) HTTP
(ii) FTP
(iii) TCP
(iv) POP3

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Q. Which one of the following is not a client server application?

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Q. Match the following:

(P) SMTP (1) Application layer
(Q) BGP (2) Transport layer
(R) TCP (3) Data link layer
(S) PPP (4) Network layer
(5) Physical layer

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Q. In the following pairs of OSI protocol layer/sub-layer and its functionality, the INCORRECT pair is

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Q. Choose the best matching between Group 1 and Group 2.

Group-1 Group-2
P. Data link 1. Ensures reliable transport of data over a physical point-to-point link

Q. Network layer 2. Encoder/decodes data for physical transmission

R. Transport layer 3. Allows end-to-end communication between two processes

4. Routes data from one network node to the next

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