enlist the various function of data link layer

... Upper Layer Services to the Media 11 ã To support a wide variety of network functions, the Data Link layer is often divided into two sublayers: an upper sublayer and an lower sublayer. – The ... consists of virtual connections between the nodes of a network independent of their physical layout. – These logical signal paths are defined by Data Link layer protocols. ã The Data Link layer ... Overview Upon completion of this chapter, you will be able to: ã Explain the role of Data Link layer protocols in data transmission. ã Describe how the Data Link layer prepares data for transmission...

Ngày tải lên: 22/12/2013, 13:17

... and Prepare for the Future Business can optimize their data centers by selecting data center infrastructure solutions that work together. By recognizing the value of the data center infrastructure ... Cabling With the same percentage of terminations as copper, fiber optic cabling and connectivity is a significant part of the data center. Fiber links are also the most critical links because they ... benefits and savings throughout the life of your data center. The Three Principles of Data Center Infrastructure Design Page 7 Deployment The graphic below depicts a sample data center using ADC's...

Ngày tải lên: 24/01/2014, 11:20

... in all of these conditions [22]. In the trau- matically injured brain, however, the synthesis of MT1 and MT2, as well as the synthesis of GIF, are up-regu- lated by reactive astrocytes in the vicinity ... loss in the AD brain. Further investigation of the increased neurotrophic activity of the AD brain revealed that it correlated with the loss of a specific neuroinhibitory factor, rather than the presence ... inhibit neurite outgrowth (as described above). The functional role of GIF synthesis and secretion in the brain Taken together, the regulation of GIF synthesis by reactive astrocytes, and its subsequent...

Ngày tải lên: 16/02/2014, 15:20

... some the stabilities of the distribution function of η in the following sense: the small changes in the distribution function of ξ k only lead to the small changes in the distribution function of ... Ψ(x) is the distribution function of η with the characteristic function ψ(x) respecrively then (see [1] or [2]) ψ(x) = a[ϕ(t)] (2) where a(z) is the generating function of ν and ϕ(t) is the characteristic ... characteristic function of ξ k . In [1] and [2], we gave some the stabilities of Ψ(x) in the following sence: the small changes in the distribution function F (x) only lead to the small changes in the distribution...

Ngày tải lên: 14/03/2014, 13:20

... and the proper length depends on the height of the person. To determine the size needed, the person should hold his hands above his head and choose the ski that most closely approximates the ... 1997 ClassificationThe Various Types of Skiing Every four years in the Winter Olympics, we see professional athletes compete in many areas ranging from downhill skiing to high-speed bobsledding. We see the professionals ... non-professionals can get into them. In this essay I will classify the various types of skiing into three categories and inform you about each. The first type of skiing that I will discuss is...

Ngày tải lên: 02/04/2014, 18:01

... a piece of glass (for what was true of the flint and the bar of iron is true of the piece of glass, and is true of every other solid they are all held together in the lump by the attraction between their parts), and I ... well as the matter of the Lecturer. May the readers of these Lectures derive one-tenth of the pleasure and instruction from their perusal which they gave to those who had the happiness of hearing them! W. CROOKES ặTHERFORCE ... hand before us, and I then take a piece of thread and an ivory ball, and hang that upon the awl then the centre of gravity of both the pasteboard and the ball and string are as near as they can get to the centre of the earth; that is to say, the...

Ngày tải lên: 04/06/2014, 12:40

... THE FRACTAL STRUCTURE OF DATA REFERENCE Applications to the Memory Hierarchy by Bruce McNutt International Business Machines ... London /Moscow The Kluwer International Series on ADVANCES IN DATABASE SYSTEMS Series Editor Ahmed K. Elmagarmid PurdueUniversity West Lafayette, IN 47907 Other books in the Series: SEMANTIC ... LOGIC IN DATA MODELING, Guoqing Chen ISBN: 0 - 7923 - 8253 - 6 INTERCONNECTING HETEROGENEOUS INFORMATION SYSTEMS, Athman FOUNDATIONS OF KNOWLEDGE SYSTEMS: With Applications to Databases DATABASE...

Ngày tải lên: 03/07/2014, 08:20

... a function of 1.7 CICS storage pools: cache performance as a function of 1.8 IM S storage pools: cache performance as a function of 1.9 TSO storage pools: cache performance as a function of ... storage as a function of window size. Persistent track images as a function of window size. Persistent cylinder images as a function of window size. Persistent file storage as a function of window ... as a function of window size. 95 Requests to persistent cylinder images as a function of window size. 95 Requests to persistent files as a function of window size. 96 Distribution of file...

Ngày tải lên: 03/07/2014, 08:20

... practical applications of such results. The focus of the applications examined in this book is on the portion of a computer system’s memory hierarchy that lies below the level of the “get” and “put” ... book. Instead, the “meat” of the present book comes from the ability of the hierarchical reuse model to impose a mathematically tractable structure on important problems involving the operation ... based upon the explicitly hierarchical nature of most software. To reflect the inferred “behind the scenes” role of hierarchically structured soft - ware, we adopt, in Chapter 1, the term hierarchical...

Ngày tải lên: 03/07/2014, 08:20

... 3 the LRU list, other than the requested track, remain linked together in the same order as before. This algorithm has the net effect that the tracks in the list always appear in order of the ... percent of the tracks. Since the beginning of the sorted list represents the best possible cache contents, we may apply the definition of Ω(l) to obtain the following upper bound on the hit ... sort the tracks in descending order by the rate of track references. Let N be the total number of tracks, and consider the subset first L of tracks, given by the first L < N that appear on the...

Ngày tải lên: 03/07/2014, 08:20

... use of a given track to the next reuse. Then we define the hierarchical reuse model of arrivals to the track as the hypothesis that the conditional distribution of the quantity (1.2) does ... Based upon the idea of time scales that are mirror images of each other, we should expect that the short term track has the same probability of being referenced in the next 5 seconds, as the long ... widely separated from any other reference to the data. If we now examine the structure of database software, in an effort to account for data reuse at a variety of time scales, we find that...

Ngày tải lên: 03/07/2014, 08:20

... size. Then we may conclude that the population of tracks currently visiting the cache is given by (1.13): THE FRACTAL STRUCTURE OF DATA REFERENCE Therefore, By contrast, measurements of the ... Let the average duration of the front end be called ∆τ. Thus, the total average duration of the visit as a whole is given by (1.7) Suppose, now, that the cumulative distribution function of the ... of requests, followed by a relatively much longer period in which the track ages out of the cache. The vast majority of tracks, visiting a real cache, tend to exhibit exactly the pattern of...

Ngày tải lên: 03/07/2014, 08:20

... substitution: (1.22) As another example, we can use successive substitutions to express the miss ratio as a function of cache size. Just as the miss ratio, as a function of the single - reference ... residency time, takes the form of a simple power law, so does the miss ratio, as a function of cache memory: (1.23) The existence of a power law relationship between these quantities was first ... n tch . We may then estimate To apply the conclusion just stated as a method of trace analysis, we count (1.17) Note that if 6’ is in the general ballpark of the guestimate (1.6), then the estimate...

Ngày tải lên: 03/07/2014, 08:20

... early demotion of sequential data residing in the cache; the memory for such data is typically freed long before the data would have progressed from the top to the bottom of the LRU list. Storage ... in the cache by itself, assuming that the cache’s single - reference residency time is held fixed. The effect of processor buffering is, therefore, to reduce the number of requests to the ... the processor buffer area and the storage subsystem, since it is necessary to ensure that the new information will be permanently retained (the new data must be hardened), One copy of the data, ...

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20

Ngày tải lên: 03/07/2014, 08:20