Recent questions and answers in Computer Networks

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In distance vector routing how the distance vectors are update when two paths have same cost eg. Initial Distance vector of A B C D are A- [0 &infin; 1 2] B- [&infin; 0 3 2] C- [1 3 0 &infin;] D- [2 2 &infin; 0] what will be distance vector of A after 1 iteration. Please mention via node and why u choose that node??
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Consider a router is working based on the Distance Vector Routing Algorithm. Consider the five-node network of the following figure. Assume all nodes building distance from that node to $A$ (number of hops) and after initial set up, suddenly either $A$ goes down or the link between $A$ and $B$ is cut. What are the distance ... $(C) B - 4, C - 5, D - 4, E - 5$ $(D)$ None
1 vote
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Consider a network system having 4 routers P,Q,R AND S as shownbelow.initially, the routersise Distance vector routing and use number of hops as distance metric. Initially, link p-q was down and all other routers agree p is unreachable.thr link p-q comes back up. ... will not be "count to infinity" problem as all routers are sending the information at the same instant. How to solve this ques?
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Station $A$ uses $32$ byte packets t transmit messages to station $B$ using sliding window protocol. The round trip delay between $A$ and $B$ is $40$ milliseconds and the bottleneck bandwidth on the path between $A$ and $B$ is $64$ kbps. The optimal window size of $A$ is $20$ $10$ $30$ $40$
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Suppose there are $n$ stations in a slotted $LAN$. Each station attempts to transmit with a probability $P$ in each time slot. The probability that only one station transmits in a given slot is $nP(1-P)^{n-1}$ $nP$ $P(1-P)^{n-1}$ $n^{P}(1-P)^{n-1}$
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Virtual circuit is associated with a __________ service. Connectionless Error-free Segmentation Connection-oriented
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Which transport class should be used with residual-error network layer ? $TP0, TP2$ $TP1, TP3$ $TP1, TP3, TP4$ $TP0, TP1, TP2, TP3, TP4$
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Which transport class should be used with a perfect network layer ? $TP0$ and $TP2$ $TP1$ and $TP3$ $TP0, TP1, TP3$ $TP0, TP1, TP2, TP3, TP4$
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Making sure that all the data packets of a message are delivered to the destination is _________ control. Error Loss Sequence Duplication
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Error control is needed at the transport layer because of potential error occurring __________. from transmission line noise in router from out of sequency delivery from packet losses
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The best known example of a MAN is : Ethernet Cable Television FDDI IEEE $802.3$
1 vote
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The process of converting the analog sample into discrete form is called Modulation Multiplexing Quantization Sampling
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Application layer protocol defines: types of messages exchanged rules for when and how processes send and respond to messages message format, syntax and semantics all of the above
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The first Network: ARPANET. NFSNET. CNNET. ASAPNET.
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How many bits are required to encode all twenty six letters, ten symbols, and ten numerals? $5$ $6$ $7$ $46$
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In networking terminology UTP means Unshielded Twisted pair Ubiquitious Teflon port Uniformly Terminating port Unshielded T- connector port
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Given a mask, M=255.255.255.248. How many subnet bits are required for given mask M? (A) 2 (B) 3 (C) 4 (D)5
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Firewall is a device that filters access to the protected network from the outside network. Firewalls can filter the packets on the basis of Source IP address Destination IP address TCP Source Port UDP Source Port TCP Destination Port Choose the correct answer from the options given below: $(a), (b)$ and $(c)$ only $(b)$ and $(e)$ only $(c)$ and $(d)$ only $(a), (b), (c), (d)$ and $(e)$ only
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Which among the following statement(s) is(are) true? A hash function takes a message of arbitrary length and generates a fixed length code A hash function takes a message of fixed length and generates a code of variable length A hash function may give same hash value for distinct messages Choose the correct ... options given below: $(a)$ only $(b)$ and $(c)$ only $(a)$ and $(c)$ only $(b)$ only
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Protocols in which the sender sends one frame and then waits for an acknowledgment before proceeding for next frame are called as ______ Simplex protocols Unrestricted simplex protocols Simplex stop and wait protocols Restricted simplex protocols
1 vote
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Consider the three-way handshake mechanism followed during $\text{TCP}$ connection establishment between hosts $P$ and $Q$. Let $X$ and $Y$ be two random $32$-bit starting sequence numbers chosen by $P$ and $Q$ respectively. Suppose $P$ sends a $\text{TCP}$ connection request message to $Q$ with a ... $\text{SEQ}$ number $=Y$, $\text{ACK}$ bit $=1$, $\text{ACK}$ number $=X$, $\text{FIN}$ bit $=0$
1 vote
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The routine table of a router is shown below : Destination  subnet  Interface  132.81.0.0 255.225.0.0 eth0 132.81.64.0 255.255.224.0 eth1 132.81.68.0 255.255.255.0 eth2 132.81.68.64 255.255.255.224 eth3 A packet begining a destination address 132.81.68.132 arrive at the router . on which of the interfaces it cant be forwarded ? a) eth 0 b ) eth 1 c) eth 2 d) eth 3
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A class B network address 130.50.0.0 is submitted as follows. The last 10 bits of the host id are allotted for host number and the remaining 6 bits are reserved for subnet number. How many subnets and number of hosts in each subnet are possible with above scheme ? 62,1022 30,510 14,254 None of these ... ? 130.50.4.1 and 130.50.16.1 130.50.1.1 and 130.50.4.1 130.50.0.0 and 130.50.3.0 None of these
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If link transmits 4000 frames per scond and each slot has 8 bits , the transmission rate of circuits of this TDM is _____ 64 Kbps 32 Mbps 32 Kbps 64 Mbps
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Consider the following two statements. $S_1$: Destination $\text{MAC}$ address of an $\text{ARP}$ reply is a broadcast address. $S_2$: Destination $\text{MAC}$ address of an $\text{ARP}$ request is a broadcast address. Which one of the following choices is correct? Both $S_1$ and $S_2$ are true $S_1$ is true and $S_2$ is false $S_1$ is false and $S_2$ is true Both $S_1$ and $S_2$ are false
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Consider a network using the pure $\text{ALOHA}$ medium access control protocol, where each frame is of length $1,000$ bits. The channel transmission rate is $1$ Mbps ($=10^6$ bits per second). The aggregate number of transmissions across all ... as the average number of frames successfully transmitted per second. The throughput of the network (rounded to the nearest integer) is ______________
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Following $7$ ... (assuming that at most $1$ bit could be corrupted). If the message contains an error find the bit which is erroneous and gives correct message.
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A $\text{TCP}$ server application is programmed to listen on port number $P$ on host $S$. A $\text{TCP}$ client is connected to the $\text{TCP}$ server over the network. Consider that while the $\text{TCP}$ connection was active, the server machine $S$ crashed ... it will receive a $\text{RST}$ segment If the client sends a packet after the server reboot, it will receive a $\text{FIN}$ segment
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Consider the cyclic redundancy check $\text{(CRC)}$ based error detecting scheme having the generator polynomial $X^3+X+1$. Suppose the message $m_4m_3m_2m_1m_0=11000$ is to be transmitted. Check bits $c_2c_1c_0$ are appended at the end of the message by the ... bit string is denoted by $m_4m_3m_2m_1m_0c_2c_1c_0$. The value of the checkbit sequence $c_2c_1c_0$ is $101$ $110$ $100$ $111$
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Q.1 how many crosspoints are needed if we use crossbar switch to connect 1000 telephones in small town.
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Consider two hosts $P$ and $Q$ connected through a router $R$. The maximum transfer unit $\text{(MTU)}$ value of the link between $P$ and $R$ is $1500$ bytes, and between $R$ and $Q$ is $820$ bytes. A $TCP$ segment of size $1400$ bytes was ... lost, $P$ is required to resend the whole $\text{TCP}$ segment. $\text{TCP}$ destination port can be determined by analysing only the second fragment.
1 vote
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Consider a computer network using the distance vector routing algorithm in its network layer. The partial topology of the network is shown below. The objective is to find the shortest-cost path from the router $R$ to routers $P$ and $Q$. Assume that $R$ does not initially know the shortest routes ... for a packet from $R$ to $P$ is $Y$ The next hop router for a packet from $R$ to $Q$ is $Z$
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Assume that a $12$-bit Hamming codeword consisting of $8$-bit data and $4$ check bits is $d_8d_7d_6d_5c_8d_4d_4d_3d_2c_4d_1c_2c_1$ ... $0$ $x$ is $0$ and $y$ is $1$ $x$ is $1$ and $y$ is $0$ $x$ is $1$ and $y$ is $1$
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Consider the sliding window flow-control protocol operating between a sender and a receiver over a full-duplex error-free link. Assume the following: The time taken for processing the data frame by the receiver is negligible. The time taken for processing the ... of the number of frames, (rounded to the nearest integer) needed to achieve a link utilization of $50\%$ is_____________.
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Consider A lives in Delhi, connected to the internet via a 100 Mbps connection retrieve a 250 KB webpage from server in Chennai where page contain 3 images of 500 KB each. Assume one way propagation delay is 75ms and A's access link is the bandwidth bottleneck for this ... to appear on A's screen using nonpersistent Http and T2 is time using persistent Http then,what are the values of T1 and T2?
1 vote
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Suppose you needed to use HTTP to download a webpage with three embedded images. The total number messages saved between the client and server starting from initiates TCP connection to receive the third object and close connection when using persistent HTTP without pipelining instead of non-persistent HTTP are?
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Consider Amit lives in Delhi,connected to the internet via a $100 \hspace{0.1cm}Mbps$ connection retrieves a $250 \hspace{0.1cm} KB$ webpage from server in Bangalore, where page contain $3$ images of $500 \hspace{0.1cm} KB$ ... $HTTP$ and $T2$ is time using persistent connection then $T=T1-T2$ will be ......msec. (Assuming queuing delay is zero)
Which of the following statements is FALSE for the generator $x^{6}$+1? S1: This generator can detect all burst errors with a length of 5 bits. S2: This generator can detect some but not all burst errors with a length of 6 bits.