Computer Networks

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Advanced Computer Networks— CSE952 Fall 2013 Take-Home Pretest

1. Fill in the blanks with the correct answer (2 pts. each). For the multiplechoice questions, pick all the correct choices for credit. (4 pts. each) [Total 20 points.] (a) In IPv4 Class D address are used for (b) There can be number. (c) TCP uses (d) TCP connections are duplex). (e) TCP and UDP are both the layer. packets. Class A addresses using IPv4. Give precise handshake protocol for connection establishment. connections (simplex/half-duplex/fulllayer protocols. Give the name of

(f) Source routing is usually not efficient and definitely not fault-tolerant. However, source routing can be useful for . (g) IP provides the following functions: (i) Reliable delivery of packets across a network. (ii) Unreliable delivery of packets across a network. (iii) Guaranteed delivery of packets within a certain time. (h) TCP provides the following functions: (i) Implements reliability on top of the IP/network layer. (ii) Provides a byte-stream abstraction to the application layer. (iii) Implements flow control and congestion control.

2. In the formula to compute the estimated RTT, explain the significance of the parameter α. Briefly state the effects of high and low values for this parameter (High α and low α). (50 words or less) [10 points]

3. A message of size m bits is to be transmitted over an L-hop path in a storeand-forward packet network as a series of consecutive packets, each containing k data bits and h header bits. Assume that m >> k + h. The bit rate of each link is R bits/second. Propagation and queueing delays are negligible (Hint: In a store-and-forward packet network, packets must be received fully before they can transmitted over the next hop. How are consecutive packets sent over successive links? Think pipelining!). (a) What is the total number of bits that must be transmitted across any one link? [10 points]

(b) What is the total delay experienced by the message (i.e., the...