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Thread: please i need help to convert fecn algorithm pseudocode to java code

  1. #1
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    Default please i need help to convert fecn algorithm pseudocode to java code

    Per-Port Switch Variables:
    Nominal Capacity of the Port: C0
    Advertised Rate for the ith interval: ri
    Port State: Port Initialized
    Measured Port Capacity for ith Measurement Interval: Ci
    Bits received in the last measurement interval: bits received
    Bits transmitted in the last measurement interval: bits sent
    Bits in Queue at the beginning of current measurement interval: qlen
    Total Busy (transmit) time during last measurement interval: time busy
    Limited rate increase: r
    Algorithm Parameters:
    Initial Rate Divider: N0
    Measurement Interval in Switches: T
    T is also used for -timer (probe interval) in the sources
    Queue Control Parameters: a, b, c
    Exponential moving average: 
    Operational Parameters:
    Queue equilibrium: Qeq
    Queue Length under severe congestion: Qsc
    Default Values:
    N0 = 200, T = 1 ms,
    Qeq = 192, 000 bits, a = 1.1, b = 1.002, c = 0.1,  = 0.5
    Variable Initialization:
    Ci = C0, r = ri−1 = ri−2 = C0
    N0
    ,
    1
    Port Initialized = FALSE.
    Switch Event Routines:
    procedure EVENT T Timer Expired Routine()
    1: while T timer expires do
    2: if Port Initialized then
    3: Estimate Capacity()
    4: if bits received > 0 then
    5: Rate Allocation(qlen, bits received, ri−1, ri−2,Ci)
    6: else
    7: ri = C0
    N0
    8: end if
    9: else
    10: if bits received > 0 then
    11: Port Initialized = TRUE
    12: Rate Allocation(qlen, bits received, ri−1, ri−2,Ci)
    13: end if
    14: end if
    15: Reset T timer
    16: end while
    procedure EVENT Transmit Packet()
    1: if packet is tagged then
    2: if Rate in Tag  ri OR Rate in Tag == −1 then
    3: Rate in Tag = ri
    4: end if
    5: end if
    6: Forward the packet
    Subroutines:
    procedure Rate Allocation(qlen, bits received, ri−1, ri−2,Ci)
    1: Queue Control(fq, qlen,Qeq)
    2:  = bits received
    TCfq
    3: if  == 0 then
    4: if qlen < 1 then
    5: ri = Ci
    6: else
    7: ri = ri&#8722;1
    8: end if
    9: else
    2
    10: ri = min{Ci, ri&#8722;1
     }
    11: end if
    12: Exponential Averaging(ri, ri&#8722;1, ri&#8722;2)
    13: Limit Rate Increase(ri, ri&#8722;1, qlen,Qeq,r)
    14: Variable Capapcity Adjustment(Ci,Ci&#8722;1, ri, ri&#8722;1, ri&#8722;2)
    15: bits received = 0
    procedure Queue Control(fq, qlen,Qeq)
    1: if qlen  Qeq then
    2: fq = bQeq
    (b&#8722;1)qlen+Qeq
    3: else
    4: fq = max
    n
    c, aQeq
    (a&#8722;1)qlen+Qeq
    o
    5: end if
    Note: Queue control function can be implemented as a precomputed table
    procedure Exponential Averaging(ri, ri&#8722;2)
    1: ri = ri + (1 &#8722; )ri&#8722;2
    procedure Limit Rate Increase(ri, ri&#8722;1, qlen,Qeq,r)
    1: if qlen < Qeq then
    2: r = 1.414r
    3: else if qlen > Qsc then
    4: r = 0.707r
    5: end if
    6: if ri &#8722; ri&#8722;1 > r then
    7: ri = ri&#8722;1 + r
    8: end if
    procedure Variable Capacity Adjustment(Ci,Ci&#8722;1, ri, ri&#8722;1, ri&#8722;2)
    1: if Ci < Ci&#8722;1 then
    2: ri = Ci
    Ci&#8722;1
    ri
    3: ri&#8722;1 = Ci
    Ci&#8722;1
    ri&#8722;1
    4: end if
    5: ri&#8722;2 = ri&#8722;1
    6: ri&#8722;1 = ri
    3
    procedure Estimate Capacity(Ci, bits sent, time busy)
    1: Ci = bits sent
    time busy
    2: bits sent = 0
    3: time busy = 0
    Source Variables:
    Current Rate: R
    Source Parameters:  = T
    Feedback Valid Interval: 2T
    Initial Rate: R0 = C0
    N0
    Source Initialization:
    Set  timer to expired
    Tagging a sampled packet every  sec
    Set Feedback Valid Timer to expired
    Source Event Routines:
    procedure EVENT Send packet()
    1: if  timer expired then
    2: if Feedback Valid timer expired then
    3: R = R0
    4: end if
    5: Tag an outgoing packet and the rate field in Tag is set as -1;
    6: Send following packets at current rate R
    7: Reset  timer
    8: else
    9: Send following packet without tag at rate R
    10: end if
    procedure EVENT FECN Received()
    1: Set R to rate received
    2: Reset Feedback Valid Timer to 2T
    Attached Files Attached Files


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: please i need help to convert fecn algorithm pseudocode to java code

    Do you have any specific questions about the code you are trying to write?
    What have you written so far?
    If you don't understand my answer, don't ignore it, ask a question.

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