00001 00002 /* 00003 * asim.h 00004 * Copyright (C) 2000 by the University of Southern California 00005 * $Id: asim.h,v 1.3 2005/08/25 18:58:01 johnh Exp $ 00006 * 00007 * This program is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU General Public License, 00009 * version 2, as published by the Free Software Foundation. 00010 * 00011 * This program is distributed in the hope that it will be useful, 00012 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 * GNU General Public License for more details. 00015 * 00016 * You should have received a copy of the GNU General Public License along 00017 * with this program; if not, write to the Free Software Foundation, Inc., 00018 * 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. 00019 * 00020 * 00021 * The copyright of this module includes the following 00022 * linking-with-specific-other-licenses addition: 00023 * 00024 * In addition, as a special exception, the copyright holders of 00025 * this module give you permission to combine (via static or 00026 * dynamic linking) this module with free software programs or 00027 * libraries that are released under the GNU LGPL and with code 00028 * included in the standard release of ns-2 under the Apache 2.0 00029 * license or under otherwise-compatible licenses with advertising 00030 * requirements (or modified versions of such code, with unchanged 00031 * license). You may copy and distribute such a system following the 00032 * terms of the GNU GPL for this module and the licenses of the 00033 * other code concerned, provided that you include the source code of 00034 * that other code when and as the GNU GPL requires distribution of 00035 * source code. 00036 * 00037 * Note that people who make modified versions of this module 00038 * are not obligated to grant this special exception for their 00039 * modified versions; it is their choice whether to do so. The GNU 00040 * General Public License gives permission to release a modified 00041 * version without this exception; this exception also makes it 00042 * possible to release a modified version which carries forward this 00043 * exception. 00044 * 00045 */ 00046 00047 // author: Debojyoti Dutta 00048 00049 00050 #ifndef _RED_ROUTER_H_ 00051 #define _RED_ROUTER_H_ 00052 00053 #include <assert.h> 00054 #include <stdio.h> 00055 #include <math.h> 00056 00057 00058 class RedRouter { 00059 double MinTh, MaxTh, MaxP; 00060 double Lambda_L; 00061 double Lambda_H; 00062 00063 void Populate(); 00064 public: 00065 RedRouter(int mTh, int MTh, double MP) { 00066 MinTh = mTh; 00067 MaxTh = MTh; 00068 MaxP = MP; 00069 Populate(); 00070 } 00071 double ComputeProbability(double Lambda, double &Delay); 00072 short Identical(int mTh, int MTh, double MP) { 00073 return (mTh == MinTh && 00074 MTh == MaxTh && 00075 MP == MaxP); 00076 } 00077 }; 00078 00079 void RedRouter::Populate() { 00080 // rho = Lambda_L: p = 0 => rho/(1-rho) = MinTh 00081 Lambda_L = ((double)MinTh)/((double)(1+MinTh)); 00082 00083 // rho = Lambda_H: p = Max_p => rho(1-Max_p)/(1-rho(1-Max_p)) = MaxTh; 00084 if (MaxP < 1) 00085 Lambda_H = ((double)MaxTh)/((double)(1+MaxTh))/(1-MaxP); 00086 } 00087 00088 00089 double RedRouter::ComputeProbability(double Lambda, double &delay) { 00090 double p; 00091 00092 if (Lambda <= Lambda_L) { 00093 delay = Lambda/(1-Lambda); 00094 return 0; 00095 } 00096 00097 if (MaxP < 1 && Lambda > Lambda_H) { 00098 delay = MaxTh; 00099 p = (Lambda - Lambda_H*(1 - MaxP))/Lambda; 00100 return p; 00101 } 00102 00103 // Solve the quadratic a.p^2 + b.p + c = 0 00104 double a, b, c; 00105 a = Lambda * (MaxTh - MinTh)/(MaxP); 00106 b = (MaxTh - MinTh)*(1-Lambda)/MaxP + MinTh * Lambda + Lambda; 00107 c = MinTh*(1-Lambda)-Lambda; 00108 00109 p = (-b + sqrt(b*b - 4 * a * c))/(2 * a); 00110 delay = Lambda*(1-p)/(1-(Lambda*(1-p))); 00111 return p; 00112 } 00113 00114 00115 #endif 00116 00117 00118 00119 00120 00121
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