red.h

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/*
 * Copyright (c) 1990-1997 Regents of the University of California.
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 *    notice, this list of conditions and the following disclaimer in the
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 *    must display the following acknowledgement:
 *      This product includes software developed by the Computer Systems
 *      Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * Here is one set of parameters from one of my simulations:
 * 
 * ed [ q_weight=0.002 thresh=5 linterm=30 maxthresh=15
 *         mean_pktsize=500 dropmech=random-drop queue-size=60
 *         plot-file=none bytes=false doubleq=false dqthresh=50 
 *         wait=true ]
 * 
 * 1/"linterm" is the max probability of dropping a packet. 
 * There are different options that make the code
 * more messy that it would otherwise be.  For example,
 * "doubleq" and "dqthresh" are for a queue that gives priority to
 *   small (control) packets, 
 * "bytes" indicates whether the queue should be measured in bytes 
 *   or in packets, 
 * "dropmech" indicates whether the drop function should be random-drop 
 *   or drop-tail when/if the queue overflows, and 
 *   the commented-out Holt-Winters method for computing the average queue 
 *   size can be ignored.
 * "wait" indicates whether the gateway should wait between dropping
 *   packets.
 *
 * @(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/queue/red.h,v 1.41 2002/04/30 17:24:20 sfloyd Exp $ (LBL)
 */

#ifndef ns_red_h
#define ns_red_h

#include "queue.h"

#include "trace.h"
class LinkDelay;

/*
 * Early drop parameters, supplied by user
 */
struct edp {
        /*
         * User supplied.
         */
        int mean_pktsize;       /* avg pkt size, linked into Tcl */
        int idle_pktsize;       /* avg pkt size used during idle times */
        int bytes;              /* true if queue in bytes, false if packets */
        int wait;               /* true for waiting between dropped packets */
        int setbit;             /* true to set congestion indication bit */
        int gentle;             /* true to increases dropping prob. slowly *
                                 * when ave queue exceeds maxthresh. */
        double th_min;          /* minimum threshold of average queue size */
        double th_min_pkts;     /* always maintained in packets */
        double th_max;          /* maximum threshold of average queue size */
        double th_max_pkts;     /* always maintained in packets */
        double max_p_inv;       /* 1/max_p, for max_p = maximum prob.  */
                                /* adaptive RED: the initial max_p_inv     */   
        double mark_p;          /* when p < mark_p, mark chosen packets */
                                /* when p > mark_p, drop chosen packets */
        double q_w;             /* queue weight given to cur q size sample */
        int adaptive;           /* 0 for default RED */
                                /* 1 for adaptive RED, adapting max_p */
        int cautious;           /* 0 for default RED */
                                /* 1 for not dropping/marking when the */
                                /*  instantaneous queue is much below the */
                                /*  average */
        double alpha;           /* adaptive RED: additive param for max_p */
        double beta;            /* adaptive RED: multip param for max_p */
        double interval;        /* adaptive RED: interval for adaptations */
        double targetdelay;     /* adaptive RED: target queue size */
        double top;             /* adaptive RED: upper bound for max_p */
        double bottom;          /* adaptive RED: lover bound for max_p */
        int feng_adaptive;      /* adaptive RED: Use the Feng et al. version */
                        
        /*
         * Computed as a function of user supplied paramters.
         */
        double ptc;             /* packet time constant in packets/second */
        double delay;           /* link delay */
};

/*
 * Early drop variables, maintained by RED
 */
struct edv {
        TracedDouble v_ave;     /* average queue size */
        TracedDouble v_prob1;   /* prob. of packet drop before "count". */
        double v_slope;         /* used in computing average queue size */
                                /* obsolete */
        double v_prob;          /* prob. of packet drop */
        double v_a;             /* v_prob = v_a * v_ave + v_b */
        double v_b;
        double v_c;             /* used for "gentle" mode */
        double v_d;             /* used for "gentle" mode */
        int count;              /* # of packets since last drop */
        int count_bytes;        /* # of bytes since last drop */
        int old;                /* 0 when average queue first exceeds thresh */
        TracedDouble cur_max_p; //current max_p
        double lastset;         /* adaptive RED: last time adapted */
        enum Status {Above, Below, Between}; // for use in Feng's Adaptive RED
        Status status;
        edv() : v_ave(0.0), v_prob1(0.0), v_slope(0.0), v_prob(0.0),
                v_a(0.0), v_b(0.0), count(0), count_bytes(0), old(0), 
                cur_max_p(1.0) { }
};

class REDQueue : public Queue {
 public:        
        /*      REDQueue();*/
        REDQueue(const char * = "Drop");
 protected:
        int command(int argc, const char*const* argv);
        void enque(Packet* pkt);
        virtual Packet *pickPacketForECN(Packet* pkt);
        virtual Packet *pickPacketToDrop();
        Packet* deque();
        void initialize_params();
        void reset();
        void run_estimator(int nqueued, int m); /* Obsolete */
        double estimator(int nqueued, int m, double ave, double q_w);
        void updateMaxP(double new_ave, double now);
        void updateMaxPFeng(double new_ave);
        int drop_early(Packet* pkt);
        double modify_p(double p, int count, int count_bytes, int bytes,
           int mean_pktsize, int wait, int size);
        double calculate_p_new(double v_ave, double th_max, int gentle, 
          double v_a, double v_b, double v_c, double v_d, double max_p);
        double calculate_p(double v_ave, double th_max, int gentle, 
          double v_a, double v_b, double v_c, double v_d, double max_p_inv);
        virtual void reportDrop(Packet *pkt) {}  //pushback
        void print_summarystats();
        int summarystats_;      /* true to print true average queue size */

        LinkDelay* link_;       /* outgoing link */
        int fifo_;              /* fifo queue? */
        PacketQueue *q_;        /* underlying (usually) FIFO queue */
                
        int bcount_() { return q_->byteLength(); };             
                        /* OBSOLETED - USE q_->byteLength() INSTEAD */
        int qib_;               /* bool: queue measured in bytes? */
        NsObject* de_drop_;     /* drop_early target */

        //added to be able to trace EDrop Objects - ratul
        //the other events - forced drop, enque and deque are traced by a different mechanism.
        NsObject * EDTrace;    //early drop trace
        char traceType[20];    //the preferred type for early drop trace. 
                               //better be less than 19 chars long

        Tcl_Channel tchan_;     /* place to write trace records */
        TracedInt curq_;        /* current qlen seen by arrivals */
        void trace(TracedVar*); /* routine to write trace records */

        /*
         * Static state.
         */
        int drop_tail_;         /* drop-tail */
        int drop_front_;        /* drop-from-front */
        int drop_rand_;         /* drop-tail, or drop random? */
        int ns1_compat_;        /* for ns-1 compatibility, bypass a */
                                /*   small bugfix */

        edp edp_;       /* early-drop params */
        int doubleq_;   /* for experiments with priority for small packets */
        int dqthresh_;  /* for experiments with priority for small packets */

        /*
         * Dynamic state.
         */
        int idle_;              /* queue is idle? */
        double idletime_;       /* if so, since this time */
        edv edv_;               /* early-drop variables */
        int first_reset_;       /* first time reset() is called */

        void print_edp();       // for debugging
        void print_edv();       // for debugging

};

#endif

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