Data Link Layer

It is necessary to design a link-layer protocol between two hosts that are directly connected over a lossless link of length 3000 kilometers. Assume that the link bandwidth is $10^8$ bits per second and that the propagat...

Consider the transmission of data bits 110001011 over a link that uses Cyclic Redundancy Check (CRC) code for error detection. If the generator bit pattern is given to be 1001, which one of the following options shows th...

Consider the implementation of sliding window protocol over a lossless link, with a window size of $W$ frames, where each frame is of size 1000 bits (including header). The bandwidth of the link is $100 \mathrm{kbps}\lef...

Suppose we are transmitting frames between two nodes using Stop-and-Wait protocol. The frame size is 3000 bits. The transmission rate of the channel is 2000 bps (bits/ second) and the propagation delay between the two no...

Consider the following statements : (i) Address Resolution Protocol (ARP) provides a mapping from an IP address to the corresponding hardware (link-layer) address. (ii) A single TCP segment from a sender $S$ to a receive...

Consider an Ethernet segment with a transmission speed of $10^8$ bits/sec and a maximum segment length of 500 meters. If the speed of propagation of the signal in the medium is $2 \times 10^8$ meters/sec, then the minimu...

Suppose two hosts are connected by a point-to-point link and they are configured to use Stop-end-Wait protocol for reliable data transfer. Identify in which one of the following scenarios, the utilization of the link is...

Consider the following two statements. S 1 : Destination MAC address of an ARP reply is a broadcast address. S 2 : Destination MAC address of an ARP request is a broadcast address. Which one of the following choices is c...

Consider the cyclic redundancy check (CRC) based error detecting scheme having the generator polynomial X 3 + X + 1. Suppose the message m 4 m 3 m 2 m 1 m 0 = 11000 is to be transmitted. Check bits c 2 c 1 c 0 are append...

Consider the sliding window flow-control protocol operating between a sender and a receiver over a full-duplex error-free link. Assume the following: 1. The time taken for processing the data frame by the receiver is neg...

Assume that a 12-bit Hamming codeword consisting of 8-bit data and 4 check bits is d 8 d 7 d 6 d 5 c 8 d 4 d 3 d 2 c 4 d 1 c 2 c 1 , where the data bits and the check bits are given in the following tables: Data bits d 8...

Consider a network using the pure 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 ac...

Consider that 15 machines need to be connected in a LAN using 8-port Ethernet switches. Assume that these switches do not have any separate uplink ports. The minimum number of switches needed is _____.

Suppose that in an IP-over-Ethernet network, a machine X wishes to find the MAC address of another machine Y in its subnet. Which one of the following techniques can be used for this?

Consider a simple communication system where multiple nodes are connected by a shared broadcast medium (like Ethernet or wireless). The nodes in the system use the following carrier-sense based medium access protocol. A...

For the IEEE 802.11 MAC protocol for wireless communication, which of the following statements is/are TRUE? I. At least three non-overlapping channels are available for transmissions. II. The RTS-CTS mechanism is used fo...

A network has a data transmission bandwidth of 20 × 10 6 bits per second. It uses CSMA/CD in the MAC layer. The maximum signal propagation time from one node to another node is 40 microseconds. The minimum size of a fram...

A sender uses the Stop-and-Wait ARQ protocol for reliable transmission of frames. Frames are of size 1000 bytes and the transmission rate at the sender is 80 Kbps (1Kbps = 1000 bits/second). Size of an acknowledgment is...

Consider a 128 × 10 3 bits/second satellite communication link with one way propagation delay of 150 milliseconds. Selective retransmission (repeat) protocol is used on this link to send data with a frame size of 1 kilob...

Consider a LAN with four nodes S 1 , S 2 , S 3 and S 4 . Time is divided into fixed-size slots, and a node can begin its transmission only at the beginning of a slot. A collision is said to have occurred if more than one...

Consider a CSMA/CD network that transmits data at a rate of 100 Mbps (10 8 bits second) over a 1 km(kilometer) cable with no repeaters. If the minimum frame size required for this network is 1250 bytes, what is the signa...

Consider a network connected 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...

Suppose that the stop-and-wait protocol is used on a link with a bit rate of 64 kilobits per second and 20 milliseconds propagation delay. Assume that the transmission time for the acknowledgment and the processing time...

A link has a transmission speed of 10 6 bits/sec. It uses data packets of size 1000 bytes each. Assume that the acknowledgement has negligible transmission delay, and that its propagation delay is the same as the data pr...

A bit-stuffing based framing protocol uses an 8-bit delimiter pattern of 01111110. If the output bit-string after stuffing is 01111100101, then the input bit-string is

Consider a selective repeat sliding window protocol that uses a frame size of 1 KB to send data on a 1.5 Mbps link with a one-way latency of 50 msec. To achieve a link utilization of 60%, the minimum number of bits requi...

Determine the maximum length of cable (in km) for transmitting data at a rate of 500 Mbps in an Ethernet LAN with frames of size 10,000 bits. Assume the signal speed in the cable to be 2,00,000 km/s

Frames of 1000 bits are sent over a 10 6 bps duplex link between two hosts. The propagation time is 25 ms. Frames are to be transmitted into this link to maximally pack them in transit (within the link). Suppose that the...

Let G(x) be the generator polynomial used for CRC checking. What is the condition that should be satisfied by G(x) to detect odd number of bits in error?

Frames of 1000 bits are sent over a 10 6 bps duplex link between two hosts. The propagation time is 25 ms. Frames are to be transmitted into this link to maximally pack them in transit (within the link). What is the mini...

The message 11001001 is to be transmitted using the CRC polynomial x 3 + 1 to protect it from errors. The message that should be transmitted is:

There are n stations in a slotted LAN. Each station attempts to transmit with a probability p in each time slot. What is the probability that ONLY one station transmits in a given time slot?

The distance between two stations M and N is L kilometers. All frames are K bits long. The propagation delay per kilometer is t seconds. Let R bits/second be the channel capacity. Assuming that processing delay is neglig...

Station A needs to send a message consisting of 9 packets to Station B using a sliding window (window size 3) and go-back-n error control strategy. All packets are ready and immediately available for transmission. If eve...

Station A uses 32 byte packets to transmit messages to Station B using a sliding window protocol. The round trip delay between A and B is 80 milliseconds and the bottleneck bandwidth on the path between A and B is 128 kb...

The maximum window size for data transmission using the selective reject protocol with n-bit frame sequence numbers is:

The address resolution protocol (ARP) is used for

Suppose the round trip propagation delay for a 10 Mbps Ethernet having 48-bit jamming signal is 46.4 μs. The minimum frame size is

In a network of LANs connected by bridges, packets are sent from one LAN to another through intermediate bridges. Since more than one path may exist between two LANs, packets may have to be routed through multiple bridge...

A and B are the only two stations on an Ethernet. Each has a steady queue of frames to send. Both A and B attempt to transmit a frame, collide, and A wins the first backoff race. At the end of this successful transmissio...

Which of the following is NOT true with respect to a transparent bridge and a router?

Host A is sending data to host B over a full duplex link. A and B are using the sliding window protocol for flow control. The send and receive window sizes are 5 packets each. Data packets (sent only from A to B) are all...