data link layer protocols in computer networks

... Data Link Layer Protocols- The Frame 31 • Remember that although there are many different Data Link layer protocols that describe Data Link layer frames, each frame ... this chapter, you will be able to: • Explain the role of Data Link layer protocols in data transmission. • Describe how the Data Link layer prepares data for transmission on network media. • ... very simple. • In point-to-point networks, if data can only flow in one direction at a time, it is operating as a half-duplex link. If data can successfully flow across the link from each node...

Ngày tải lên: 22/12/2013, 13:17

... source access points (DSAP, SSAP) 2 Introduction  Data link control layer – often abbreviated simply to data link layer – is concerned with the transfer of data over a serial data link  The transmission ... protocol  The data link layer is fundamental to the operation of all data communication applications 27 Character-oriented Protocols – Half-duplex Protocols  BSC 64 Bit-oriented Protocols – Link ... Environments  The data link topology may be  Point-to-point circuit  Direct physical connection  Operates on an end-to-end basis 51 Bit-oriented Protocols – HDLC (High-level Data Link Control)  Protocol...

Ngày tải lên: 30/03/2014, 07:20

... packet in downlink communication with a stop- and-wait LL-ARQ. When the wireless link layer of BS fails in the first transmission attempt of the packet 1 (Layer- 2 ACK timeout), the wireless link layer ... wireless link. In LL-ELSN, there is no additional transmission over the wireless link and thus it has no detection failure in uplink communication. LL-ELSN also has no detection failure in downlink ... RTT min updating algorithm, in which RTT min is multiplied by a reducing factor less than one. However, since the RTT min updating algorithm is invoked whenever a congestion event occurs, RTT min goes...

Ngày tải lên: 21/06/2014, 20:20

... quantitative data and permit the cost-effective assembly of large, high- quality data sets. Discussion Quantitative data generation is becoming increasingly important for obtaining insight into the ... protein standard depicted in Fig. 1. Smoothing spline curves through original and normalized data are shown as solid lines. M. Schilling et al. Strategies for standardizing quantitative data FEBS ... bio- chemical data. We use the erythropoietin receptor (EpoR)-induced activation of ERK1 in the hematopoietic suspension cell line, BaF3-hemaglutinin-tagged (HA)-EpoR, and the interleukin-6 (IL-6)-induced...

Ngày tải lên: 19/02/2014, 07:20

... integration, is undefined. If the integration interval a ~ b includes the integration of over this interval is 1 ; if lies outside of the integration interval, the integration of over the interval is ... question underpinning this book in perspective. Referring to Figure 1.1, in the beginning of telecommunications, there were in general two separate networks, one for voice and one for data. Each network ... consisting of two random experiments, “throwing a die” and “throwing a coin.” A player is to throw the die twice and the coin once. A player who gets the face with one spot in both die-throwings...

Ngày tải lên: 01/06/2014, 12:38

... hopping pattern or have individual hopping patterns. In multi-channel WLANs the common hopping approach is used for example in Channel-Hopping Multiple Access (CHMA) which was introduced in [11]. ... Multi-channel Mac for Ad Hoc Networks: Handling Multi- channel Hidden Terminals Using a Single Transceiver, in 5th ACM International Symposium on Mobile Ad Hoc Networking and Computing, MobiHoc ‘04, 222–233 ... probabilities are derived in Appendix B. The amount of successful data negotiations during an ATIM window is on average E [ packets ] = P s g a T atim . (18) In the beginning of each ATIM window all the...

Ngày tải lên: 20/06/2014, 22:20

... considering the findings in the preliminary investigation, SNR is considered as the main QoS metric at the PHY layer to determine the appropriate sensing time for cognitive users in our cross layer ... l-centric adaptation PHY layer Layer without decision freedom Determining transmission actions (c) Application layer Layer l PHY layer Middleware (d) Application adaptation Layer l adaptation PHY layer adaptation (e) Figure ... Yusof, “Sensing period considerations in fading environment for multimedia delivery in cognitive Ultra Wideband system,” in Proceedings of IEEE International Conference on Signal and Image Processing...

Ngày tải lên: 21/06/2014, 11:20

... the training set, making them unsuitable for online applications. Therefore, it was essential to first propose a mechanism for controlling the increase in the model order as new input data become ... promising subject for research. References [1] M. Rabbat and R. Nowak, “Distributed optimization in sensor networks, ” in Proceedings of the 3rd International Symposium on Information Processing in ... dynamic fields. Online optimization of this criterion by adding or removing kernel functions from the dictionary also seems interesting. Finally, in a broader perspective, controlling the movement of...

Ngày tải lên: 21/06/2014, 17:20

... allows certain important information to in uence decisions in a layer that is originally not defined to use that information (e.g., the SNR information at the link layer or the queue size at the baseband ... impact on these layers and their interaction. In recent years, the importance of the cross -layer design at the PHY/MAC /link layer has been reiterated through the emergence of many innovative techniques, ... observation that a cross -layer approach is particularly important when designing protocols at the physical (PHY) and medium access control (MAC) /link layer. This is because the defining wireless features...

Ngày tải lên: 21/06/2014, 22:20

... session termination Sends leave message JoinAck JoinReq JoinReq JoinAck Join Reply Join Request Receiver Node Y Join Reply Join Request Downstream node detects a link failure sends JoinReq JoinAck Join ... Communications and Networking 33 Virtual link Physical link Figure 32: Physical link versus virtual link. Overlay link Physical link Destination node Non-member node Source core S X Y Z Downstream ... for initializing, constructing, maintaining, and terminating a multicast session. When a source node has data to send, but no information on a route to a receiver is known, it floods a Join Request packet,...

Ngày tải lên: 21/06/2014, 22:20

... energy- efficient link layer protocol for reliable transmission over wireless sensor networks, ” in Proceedings of the IEEE Interna- tional Conference on Communications (ICC ’08), pp. 146–150, Beijing, China, ... number of data and header bits in the MAC data frame; for example, in 802.15.4, n hdr = 104 bits are used in the short addressing mode [18] and the minimum header size is 34 bytes in 802.11 networks. ... modeling the reliability of data transport in wireless sensor networks, ” in Proceedings of the15th EUROMICRO International Confer- ence on Parallel, Distributed and Network-Based Processing (PDP...

Ngày tải lên: 21/06/2014, 22:20

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