# Recent questions tagged computer-networks

I am reading packet switching vs circuit switching from computer networking a top down approach(pg no. 57) . I came across an example: Suppose there are 10 users and that one user suddenly generates one thousand 1000-bit packets, while other users remain quiescent and don't ... data has been transmitted. Now I don,t know how author got 10s as answer while i am getting 100s as answer. Kindly help.
I was scrolling through sample questions when I chanced over this question. Consider a sliding window flow control protocol between hosts A and B. Suppose the link propagation delay is 1 time unit, the retransmission timeout is 3 time units, and the window size is ... the drops? I would really appreciate any help regarding this question. Also, can someone please leave a link to similar questions?
I had a doubt regarding one scenario in Go Back N flow control algorithm. Consider the following scenario shown in the image The left hand side is the sender and the right hand side is the reciever. I referred to Kurose Ross Extended FSM Description of GBN sender and reciever ... the entire window(packets 1, 2 and 3). Is this correct? Can such a scenario even occur in real life? Thanks in advance.
Do we have hdlc and ppp protocols(flow and error control) in syllabus?
Do we have Parity check in syllabus?
Do TCP packets with PSH flag set, which are immediately pushed to the Application layer arrive out of order?
If the bandwidth is 100 Mbps, round trip time is 50sec and the frame size is 25 bits. Calculate (i) Window size used in selective repeat ARQ. (ii) Number of sequence bits in selective repeat ARQ.
Finding Optimal Window Size In Slinding Window Protocol. Given Round trip time(RTT sec), Bandwidth(BW bits/sec), packet size(L bits), which approch is right? Approch 1. max data that can be sent in RTT = RTT * BW bits max window size = (RTT * BW)/L packets Apprach 2: ... size = (1 + 2a) packets; a=Tp/Tt Some problems are sloved with approch 1 and others with 2nd one. Which one should we use?
can a host simultaneously exist in two different network?
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 $=0$
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 $101$ $110$ $100$ $111$
1 vote
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 $Z$
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 ______________
1 vote
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
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 $1$
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
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.
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_____________.
1 vote
Consider a file of 3MB that needs to be transmitted over a 1Gbps link with RTT of 80ms, What is the effective throughput? A)36.2 Mbps B)9.26Mbps C)9.9 Mbps D)28.85 Mbps
Options are: 8,4,6,7. This is a multiple correct question. Answer as per key is 8,6,7 Their explanation is this: My doubt: if the window size is 8, then why does the sender wait for acknowledgement after sending 3 packets? It can send more without waiting.
I have read rules of supernetting from a few sources and have got conflicting information. this (3:20) , this and this say that the rules are: 1.All the Networks should be contiguous. 2.The block size of every networks should be equal and must be in form of 2^ ... in power of 2 and first address being divisible by "number of blocks" in the supernet. What is going wrong? Am I missing something?
In datagrams fragmentation occurs at routers. What about in virtual circuits? As CPU bandwidth and buffers are reserved, is there a chance for fragmentation to occur in router?
consider the following figure of connection release.what will be B values ,if A is 21? in ans it is given 52.but it should be 51 bcz in connection release server sends FIN+ACK packet but ack packet does not consume any sequence number.Am i correct?
dhcp works at which layer?[ network layer or application layer] arp works at which layer?[data link layer or network layer]
Following is the Packet : 0 x 4 6 0 0 0 0 2 8 0 1 0 1 2 0 5 0 0 1 0 6 0 0 0 0 my question is that what is the size of options and how many bytes of data is being carried by this packet and what is the identification number of datagram fragment?
How many maximum numbers of hosts can be connected to in a LAN, having three 6 port switches… The answer given is 14 but I suspect.
Group of user stations(N) share a 56Kbps pure aloha channel .Each Station outputs a 1000 bits frame on an average of once every 100sec(stations are buffered). What is the max value of N?
Wrap Around Concept and TCP Sequence Number While considering the wrap around time, why are the headers not considered? Why is it considered as if the entire stretch of bytes are continuous? Or is it so that the headers are just ignored?
Consider the Go back N protocol with a sender's window size of n'. Suppose that at time t', the next inorder packet the receiver is expecting has a sequence number of K'. Assume that the medium does not reorder messages . If acknowledgements are still on their way to sender, what are all possible values of ... back to the sender at a time t'? [K-n, K-1] [K-1, K-n] [K, K-n] [K-n, K+1]
Let N station share 40kbps of a pure aloha channel.Frame size is 512 bits which are sent at every 40 seconds. The maximum value of N is _______
A network with CSMA/CD protocol in the MAC layer is running at 1 Gbps over a 1 km cable with no repeaters. The signal speed in the cable is 2 x 10^8 m/sec. The frame size for this network is 10000 bits. What is the total time required in mu sec to send this frame completely where the number of collisions occurs on an average is eccentricity e ?[ Take the floor value of the result]
Sentinel framing uses a one-bit pattern to designate the start of a frame, another bit pattern to designate the end of a frame and a bit-stuffing rule to prevent these two special patterns from occurring in the payload of the packet. The bit-stuffing ... 00111010011011011001100110001111. What bit pattern is there in start and end of the frame. 001110, 001111 00111, 01111 011101, 001111 0011, 01111
IP addresses are available starting at 201.16.0.0/16. Four organizations A, B, C & D request 300, 400, 200, and 500 addresses, respectively. For each of these, give the first IP address assigned, the last IP address assigned, and the mask in the w.x.y.z/s notation. (Assume classless addressing)