# Recent questions tagged network-switching

1
In a packet switching network, if the message size is $48$ bytes and each packet contains a header of $3$ bytes. If $24$ packets are required to transmit the message, the packet size is $2$ bytes $1$ byte $4$ bytes $5$ bytes
2
A packet switch receives a packet and determines the outbound link to which the packet should be forwarded. When the packet arrives, one other packet is halfway done being transmitted on this outbound link and four other packets are waiting to be transmitted. Packets are ... rate is R, x bits of the currently-being-transmitted packet have been transmitted, and n packets are already in the queue?
3
In the discussion of packet switching versus circuit switching with a 1 Mbps link. Users are generating data at a rate of 100 kbps when busy, but are busy generating data only with probability p = 0.1. Suppose that the 1 Mbps link is replaced by a 1 Gbps link. What is N ... user population of M users. Give a formula (in terms of p, M, N) for the probability that more than N users are sending data.
4
Suppose users share a 3 Mbps link. Also, suppose each user requires 150 kbps when transmitting, but each user transmits only 10 percent of the time. When circuit switching is used, how many users can be supported? For the remainder of this ... are transmitting simultaneously. (Hint: Use the binomial distribution.) Find the probability that there are 21 or more users transmitting simultaneously.
5
Consider the circuit-switched network in the Figure below. Recall that there are 4 circuits on each link. Label the four switches A, B, C, and D, going in the clockwise direction. What is the maximum number of simultaneous connections that can be in ... and another four connections between switches B and D. Can we route these calls through the four links to accommodate all eight connections?
6
Consider an application that transmits data at a steady rate (for example, the sender generates an N-bit unit of data every k time units, where k is small and fixed). Also, when such an application starts, it will continue running for a relatively long period of ... sum of the application data rates is less than the capacities of each and every link. Is some form of congestion control needed? Why?
7
Why will two ISPs at the same level of the hierarchy often peer with each other? How does an IXP earn money?
8
Suppose users share a 2 Mbps link. Also, suppose each user transmits continuously at 1 Mbps when transmitting, but each user transmits only 20 percent of the time. When circuit switching is used, how many users can be supported? For the remainder of this ... probability that at any given time, all three users are transmitting simultaneously. Find the fraction of time during which the queue grows.
9
What advantage does a circuit-switched network have over a packet-switched network? What advantages does TDM have over FDM in a circuit-switched network?
10
Suppose there is exactly one packet switch between a sending host and a receiving host. The transmission rates between the sending host and the switch and between the switch and the receiving host are R1 and R2, respectively. Assuming that the switch uses store-and-forward ... is the total end-to-end delay to send a packet of length L? (Ignore queuing, propagation delay, and processing delay.)
11
A datagram network allows routers to drop packets whenever they need to. The probability of a router discarding a packet is p. Consider the case of a source host connected to the source router, which is connected to the destination router, and then to the destination ... number of (a) hops a packet makes per transmission? (b) transmissions a packet makes? (c) hops required per received packet?
1 vote
12
Assuming that all routers and hosts are working properly and that all software in both is free of all errors, is there any chance, however small, that a packet will be delivered to the wrong destination?
13
Datagram networks route each packet as a separate unit, independent of all others. Virtual-circuit networks do not have to do this, since each data packet follows a predetermined route. Does this observation mean that virtual-circuit networks do not need the capability to route isolated packets from an arbitrary source to an arbitrary destination? Explain your answer.
14
Which has lower latency amongst “Switch” and “Router”. And why ?
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Suppose Host A is connected to another Host B via a switch. The data rate of the link connecting the hosts to the switch is Rbps. Assume a packet length of L bits. In the calculation below, ignore processing, propagation and queuing delay. A ---- S ---- B ... 400 kbps. If packet switching was being used, for what fraction of the time (expressed in percentage) can the queue at the switch grow?
17
A university has 150 LANs with 100 hosts in each LAN. (a) Suppose the university has one Class B address. Design an appropriate subnet addressing scheme. (b) Design an appropriate CIDR addressing scheme. A router has the following CIDR entries in its routing table: ... contain the Ethernet address of the gateway? e) How many packets (sent or received) contain the IP address of the DHCP server?
18
Consider the store and forward packet switched network where host A and B are connected via 2 routers R1 and R2 . Assume Transmission time to be 1ms and Propagation time of link to be 5ms. If a message is divided into 6 packets of equal length then total time to transfer message is _________ ?
19
Which of the following statements are true? Three broad categories of Networks are Circuit Switched Networks Packet Switched Networks Message Switched Networks Circuit Switched Network resources need not be reserved during the set up phase In packet switching there is no resource allocation for packets a and b only b and c only a and c only a, b and c
1 vote
20
If two host are connected by a link and in middle of the link there is a switch between them, then transmission and propagation time both doubled. But if for the same link, there is no switch between that two hosts, then propagation time and transmission ... be once Why that happens? Though both are operating on same link, why only a switch doubles propagation delay and transmission delay time?
21
How long does it take a packet of length L to propagate over a link of distance D, propagation speed S, and transmission rate R bps. Does this delay depend on transmission rate? Answer given is No. But I don't understand how it is possible. Until the packet is transmitted , it can't be propagate over the link.
1 vote
22
C consider the two hosts A and B are connected Via a Router R which is having a queuing delay of 7 μsec is as shown below : The Router R has two links Link1 and Link2, connected to A and B respectively. Each link is 250 meters long and has a bandwidth of 109bps ... speed is 500,000 km/sec. The total transfer delay for 2 KB packet from A to B is __________ μsec. (ignore the processing delay).
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1)What is switching? And in which layer switching happens? 2)Is circuit better than packet in OSI model? 3)Main difference between circuit switching and packet switching?