rap.h

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/*
 * rap.h
 * Copyright (C) 1997 by the University of Southern California
 * $Id: rap.h,v 1.6 2005/08/25 18:58:11 johnh Exp $
 *
 * This program is free software; you can redistribute it and/or
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 * version 2, as published by the Free Software Foundation.
 *
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 * 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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 *
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//
// rap.h 
//      Header File for the 'RAP Source' Agent Class
//
// Author: 
//   Mohit Talwar (mohit@catarina.usc.edu)
//
// $Header: /nfs/jade/vint/CVSROOT/ns-2/rap/rap.h,v 1.6 2005/08/25 18:58:11 johnh Exp $

#ifndef RAP_H
#define RAP_H

#include "ns-process.h"
#include "app.h"
#include "utilities.h"

// RapTimeoutType
//      Possible timeout events

enum RapTimeoutType 
{
    RAP_IPG_TIMEOUT,        // IPG timer fires
    RAP_RTT_TIMEOUT     // RTT timer fires
};

// RapLossType
//      Possible loss types

enum RapLossType 
{
    RAP_TIMER_BASED,        // TIMER based loss detection
    RAP_ACK_BASED           // ACK based loss detection
};

// RapPacketStatus 
//      Possible packet types in the transmission history

enum RapPacketStatusType
{
    RAP_SENT,           // Packet has been sent
    RAP_PURGED,         // Packet detected lost or received
    RAP_INACTIVE            // Cluster loss ignored
};

class TransHistoryEntry
{
public:
    TransHistoryEntry(int seq, RapPacketStatusType stat = RAP_SENT) {
        seqno = seq;
        status = stat;
        departureTime = Scheduler::instance().clock();
    };

    int seqno;
    RapPacketStatusType status;
    double departureTime;
};

// RAP packet header flags
const int RH_DATA = 0x01;
const int RH_ACK  = 0x02;

struct hdr_rap 
{
    int seqno_;     // Seq num of packet being sent/acked
    int size_;      // Size of user data inside this packet
    int rap_flags_;     // Flags to separate data/ack packets
    
    int lastRecv;       // Last hole at the RAP sink...
    int lastMiss;
    int prevRecv;

    static int offset_; // offset for this header
    inline static int& offset() { return offset_; }
    inline static hdr_rap* access(const Packet* p) {
        return (hdr_rap*) p->access(offset_);
    }

    int& seqno() { return seqno_; }
    int& size() { return size_; }
    int& flags() { return rap_flags_; }
};

class RapAgent;

class IpgTimer : public TimerHandler
{
public:
    IpgTimer(RapAgent *a) : TimerHandler() { a_ = a; }

protected:
    virtual void expire(Event *e);
    RapAgent *a_;
};

class RttTimer : public TimerHandler
{
public:
    RttTimer(RapAgent *a) : TimerHandler() { a_ = a; }

protected:
    virtual void expire(Event *e);
    RapAgent *a_;
};

// Rap flags
const int RF_ANYACK = 0x01; // Received first ack
const int RF_STOP   = 0x02; // This agent has stopped
const int RF_COUNTPKT = 0x04;    // This agent will send up to certain # of pkts

class RapAgent : public Agent   // RAP source
{
public:
    RapAgent();
    ~RapAgent();

    void recv(Packet*, Handler*);
    void timeout(int type);

    int GetSeqno() { return seqno_; }
    double GetTimeout() { return timeout_; }
    int GetDebugFlag() { return debugEnable_; }
    FILE *GetLogfile() { return logfile_; }

    void IncrementLossCount() { sessionLossCount_++; }

    void start();
    void stop();
    void listen();
    void advanceby(int delta);
    void finish();

    // Data member access methods
    double srtt() { return srtt_; }
    double ipg() { return ipg_; }

    int anyack() { return flags_ & RF_ANYACK; }
    int is_stopped() { return flags_ & RF_STOP; }
    int counting_pkt() { return flags_ & RF_COUNTPKT; }
    void FixIpg(double fipg) { fixIpg_ = fipg; }

protected:
    virtual int command(int argc, const char*const* argv);

    void IpgTimeout();      // ipgTimer_ handler
    void RttTimeout();      // rttTimer_ handler

    void IncreaseIpg() { 
        fixIpg_ = 0; 
        ipg_ /= beta_; 
    }
    void DecreaseIpg() { 
        if (fixIpg_ != 0) 
            ipg_ = fixIpg_;
        else 
            ipg_ *= srtt_ / (alpha_ * ipg_ + srtt_);
    }
  
    // Adjust RTT estimate based on sample
    void UpdateTimeValues(double sampleRtt); 

    // Detect TIMER_BASED or ACK_BASED losses
    int LossDetection(RapLossType type, hdr_rap *ackHeader = NULL);
    // Increase ipg_ and mark history INACTIVE
    void LossHandler();     

    // Send a DATA packet
    void SendPacket(int nbytes, AppData *data = 0); 
    // Process an ACK
    void RecvAck(hdr_rap *ackHeader); 

    IpgTimer ipgTimer_;     // Send event
    RttTimer rttTimer_;     // IPG decrease event

    List transmissionHistory_;  // Of packets sent out
  
    TracedInt seqno_;       // Current sequence number
    TracedInt sessionLossCount_;    // ~ Packets lost in RAP session
    TracedInt curseq_;              // max # of pkts sent

    TracedDouble ipg_;      // Inter packet gap
    double beta_;           // Decrease factor
    double alpha_;          // Increase factor 

    TracedDouble srtt_;     // Smoothened round trip time
    double variance_;       // Variance in rtt samples
    double delta_;          // Jacobson/Karl 's constants...
    double mu_;
    double phi_;

    double overhead_;       // Max random delay added to IPG

    int useFineGrain_;      // Use fine grain rate adaptation?
    double frtt_;           // Fine grain feedback signals
    double xrtt_;
    double kxrtt_;
    double kfrtt_;

    TracedDouble timeout_;  // Timeout estimate

    double startTime_, stopTime_;   // Of this agent's life

    int debugEnable_;
    FILE *logfile_;

    // Data and methods as required by RAP receiver
    int lastRecv_;      // Last hole at the RAP sink...
    int lastMiss_;
    int prevRecv_;
    void UpdateLastHole(int seqNum);
    void SendAck(int seqNum);

    int rap_base_hdr_size_;

    // Data packet counter: the number of data packets that we've sent 
    // in a RTT. If we have not sent much we should not increase 
    // rate because we don't have enough packets to probe for losses
    int dctr_;
    // The percentage threshold for increasing rate.
    int dpthresh_; 

    // Misc flags
    int flags_;
    double fixIpg_;
};

#endif // RAP_H

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