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    Leaky Bucket

    Uploaded by

    Ranjith Chandrashekar
    The leaky bucket algorithm is used to control the rate of network traffic by smoothing out bursts in the data transmission rate. It works by conceptually placing packets in a bucket with a hole, allowing a maximum of b bytes to queue. Packets drain from the bucket into the network at a constant rate r bytes per second. While it controls traffic rates, the leaky bucket implementation does not efficiently use network resources as its leak rate is fixed and portions of bandwidth may go unused when traffic is low. The token bucket algorithm allows for more efficient use of network resources during low traffic periods.

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    Leaky Bucket

    Uploaded by

    Ranjith Chandrashekar
    372 views4 pages
    The leaky bucket algorithm is used to control the rate of network traffic by smoothing out bursts in the data transmission rate. It works by conceptually placing packets in a bucket with a hole, allowing a maximum of b bytes to queue. Packets drain from the bucket into the network at a constant rate r bytes per second. While it controls traffic rates, the leaky bucket implementation does not efficiently use network resources as its leak rate is fixed and portions of bandwidth may go unused when traffic is low. The token bucket algorithm allows for more efficient use of network resources during low traffic periods.

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    The leaky bucket algorithm is used to control the rate of network traffic by smoothing out bursts in the data transmission rate. It works by conceptually placing packets in a bucket with a hole, allowing a maximum of b bytes to queue. Packets drain from the bucket into the network at a constant rate r bytes per second. While it controls traffic rates, the leaky bucket implementation does not efficiently use network resources as its leak rate is fixed and portions of bandwidth may go unused when traffic is low. The token bucket algorithm allows for more efficient use of network resources during low traffic periods.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as DOC, PDF, TXT or read online from Scribd
    Download as doc, pdf, or txt
    372 views4 pages

    Leaky Bucket

    Uploaded by

    Ranjith Chandrashekar
    The leaky bucket algorithm is used to control the rate of network traffic by smoothing out bursts in the data transmission rate. It works by conceptually placing packets in a bucket with a hole, allowing a maximum of b bytes to queue. Packets drain from the bucket into the network at a constant rate r bytes per second. While it controls traffic rates, the leaky bucket implementation does not efficiently use network resources as its leak rate is fixed and portions of bandwidth may go unused when traffic is low. The token bucket algorithm allows for more efficient use of network resources during low traffic periods.

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    The leaky bucket algorithm is a traffic shaping technique used to control the rate of data injection into a network by smoothing out burstiness. It works by storing incoming data in a virtual bucket with a hole in the bottom that drains at a fixed rate.

    The leaky bucket algorithm aims to control the rate at which traffic is sent to the network by shaping bursty traffic to present a steady stream of traffic as opposed to erratic bursts of low and high volume flows.

    Incoming packets are placed in a virtual bucket that can hold up to a certain size (b bytes). Packets drain out through the hole in the bottom at a constant rate (r bytes/second). If the bucket is full, incoming packets are discarded.

    Leaky bucket

    From Wikipedia, the free encyclopedia

    Jump to: navigation, search Although the leaky bucket algorithm has several uses, it is best understood in the context of network traffic shaping or rate limiting. Typically, the algorithm is used to control the rate at which data is injected into a network, smoothing out "burstiness" in the data rate.

    Contents
    [hide]

    1 Traffic shaping algorithms 2 What is the Leaky-Bucket algorithm used for? 3 Automobile traffic analogy 4 The Leaky-bucket algorithm 5 Inefficiency of the Leaky-bucket implementation 6 See also 7 References

    [edit] Traffic shaping algorithms


    Two predominant methods for shaping traffic exist: a leaky bucket implementation and a token bucket implementation. Sometimes the leaky bucket and token bucket algorithms are mistakenly lumped together under the same name. Both these schemes have distinct properties and are used for distinct purposes [1]. They differ principally in that the leaky bucket imposes a hard limit on the data transmission rate, whereas the token bucket allows a certain amount of burstiness while imposing a limit on the average data transmission rate.

    [edit] What is the Leaky-Bucket algorithm used for?

    Figure 1: A simple Leaky Bucket [1] The leaky-bucket implementation is used to control the rate at which traffic is sent to the network (see Figure 1). A leaky bucket provides a mechanism by which bursty traffic can be shaped to present a steady stream of traffic to the network, as opposed to traffic with erratic bursts of low-volume and high-volume flows.

    [edit] Automobile traffic analogy


    An appropriate analogy for the leaky bucket is a scenario in which four lanes of automobile traffic converge into a single lane. A regulated admission interval into the single lane of traffic flow helps the traffic move. The benefit of this approach is that traffic flow into the major arteries (the network) is predictable and controlled. The major liability is that when the volume of traffic is vastly greater than the bucket size, in conjunction with the drainage-time interval, inward traffic for the bucket and beyond bucket capacity, is discarded [1]

    [edit] The Leaky-bucket algorithm


    The algorithm can be conceptually understood as follows:

    Arriving packets (network layer PDUs) are placed in a bucket with a hole in the bottom. The bucket can queue at most b bytes. If a packet arrives when the bucket is full, the packet is discarded. Packets drain through the hole in the bucket, into the network, at a constant rate of r bytes per second, thus smoothing traffic bursts.

    The size 'b' of the bucket is limited by the available memory of the system. The Generic Cell Rate Algorithm, I , L used in traffic shaping of ATM networks is equivalent to the leaky bucket algorithm.

    [edit] Inefficiency of the Leaky-bucket implementation


    The leaky-bucket implementation does not efficiently use available network resources. Because its leak rate is a fixed parameter, there will be many instances when the traffic volume is very low and large portions of network resources (bandwidth in particular) are not being used. Therefore no mechanism exists in the leaky-bucket implementation to allow individual flows to burst up to port speed, effectively consuming network resources at times when there would not be resource contention in the network. The token bucket implementation does however accommodate traffic flows with bursty characteristics [1]. The leaky-bucket and token bucket implementations can be combined to provide maximum efficiency and control of the traffic flows into a network.

    [edit] See also


    Token bucket Traffic shaping Rate limiting Congestion Avoidance in Broadband Networks

    The Generic Cell Rate Algorithm

    [edit] References

    "Deploying IP and MPLS QoS for Multiservice Networks: Theory and Practice" by John Evans, Clarence Filsfils (Morgan Kaufmann, 2007, ISBN 0-12-370549-5) Ferguson P., Huston G., Quality of Service: Delivering QoS on the Internet and in Corporate Networks, John Wiley & Sons, Inc., 1998.

    Retrieved from "http://en.wikipedia.org/wiki/Leaky_bucket" Category: Algorithms

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