RTPAgent Class Reference

#include <rtp.h>

List of all members.

Public Member Functions
	RTPAgent ()
virtual void	timeout (int)
void	join_timeout (int)
virtual void	recv (Packet *p, Handler *)
virtual int	command (int argc, const char *const *argv)
void	advanceby (int delta)
virtual void	sendmsg (int nbytes, const char *flags=0)
Protected Member Functions
virtual void	sendpkt ()
virtual void	makepkt (Packet *)
void	rate_change ()
virtual void	start ()
virtual void	stop ()
virtual void	finish ()
Protected Attributes
RTPSession *	session_
double	lastpkttime_
int	seqno_
int	running_
int	random_
int	maxpkts_
double	interval_
RTPTimer	rtp_timer_
double	timestamp_
JoinTimer	join_timer_
int	join_flag_

---

Detailed Description

this class generates the RTP packets and controls the transmission rate through the RTP timer and the update rate function

Definition at line 458 of file rtp.h.

---

Constructor & Destructor Documentation

RTPAgent::RTPAgent

(

)

constructor initializes the RTPAgent intance

Definition at line 68 of file rtp.cc.

References interval_, join_flag_, maxpkts_, random_, seqno_, and timestamp_.

                   : Agent(PT_RTP), session_(0), lastpkttime_(-1e6),
    running_(0),  rtp_timer_(this),join_timer_(this)
{
        bind("seqno_", &seqno_);
        bind_time("interval_", &interval_);
        bind("packetSize_", &size_);
        bind("maxpkts_", &maxpkts_);
        bind("random_", &random_);
        timestamp_ = 0;
        join_flag_ = 0;
        
        
}

---

Member Function Documentation

void RTPAgent::timeout

(

int

)

[virtual]

when the RTPTimer times out the RTP Agent sends an RTP packet when there is a session (multicast session) the sending source is apdating the number of RTP packets that sends

Definition at line 141 of file rtp.cc.

References interval_, RTPSession::localsrc_update(), RTPSession::localsrc_update_nbytes(), random_, rtp_timer_, running_, sendpkt(), and session_.

Referenced by RTPTimer::expire().

{
        if (running_) {
                sendpkt();
                if (session_)
                        session_->localsrc_update(size_);
                        session_->localsrc_update_nbytes(size_);
                        
                        
                double t = interval_;
                if (random_)
                        /* add some zero-mean white noise */
                        t += interval_ * Random::uniform(-0.5, 0.5);
                rtp_timer_.resched(t);
        }
}

void RTPAgent::join_timeout

(

int

)

Definition at line 158 of file rtp.cc.

References join_flag_, join_timer_, running_, and TIMEOUT.

Referenced by JoinTimer::expire().

{
        if (running_) {
                if(join_flag_ == 0) join_flag_ = 1;
                join_timer_.resched(TIMEOUT);
        }
}

void RTPAgent::recv	(	Packet *	p,
		Handler *
	)			[virtual]

the receive method for RTP packets. It simples passes the packet to the instance of the RTPSession class. Ottherwise the mothod does nothing

Definition at line 192 of file rtp.cc.

References RTPSession::recv(), and session_.

{
        if (session_)
                session_->recv(p, 0);
        else
                Packet::free(p);
}

int RTPAgent::command	(	int	argc,
		const char *const *	argv
	)			[virtual]

Definition at line 200 of file rtp.cc.

References advanceby(), rate_change(), seqno_, session_, start(), and stop().

{
        if (argc == 2) {
                if (strcmp(argv[1], "rate-change") == 0) {
                        rate_change();
                        return (TCL_OK);
                } else if (strcmp(argv[1], "start") == 0) {
                        start();
                        return (TCL_OK);
                } else if (strcmp(argv[1], "stop") == 0) {
                        stop();
                        return (TCL_OK);
                }
        } else if (argc == 3) {
                if (strcmp(argv[1], "session") == 0) {
                        session_ = (RTPSession*)TclObject::lookup(argv[2]);
                        return (TCL_OK);
                } else if (strcmp(argv[1], "advance") == 0) {
                        int newseq = atoi(argv[2]);
                        advanceby(newseq - seqno_);
                        return (TCL_OK); 
                } else if (strcmp(argv[1], "advanceby") == 0) {
                        advanceby(atoi(argv[2]));
                        return (TCL_OK);
                }       
        }
        return (Agent::command(argc, argv));
}

void RTPAgent::advanceby

(

int

delta

)

Parameters:

delta

Definition at line 181 of file rtp.cc.

References maxpkts_, running_, seqno_, and start().

Referenced by command().

{
        maxpkts_ += delta;
        if (seqno_ < maxpkts_ && !running_)
                start();
}               

void RTPAgent::sendmsg	(	int	nbytes,
		const char *	flags = 0
	)			[virtual]

sends the packets

Definition at line 103 of file rtp.cc.

References hdr_rtp::access(), finish(), maxpkts_, hdr_rtp::seqno(), seqno_, and start().

{
        Packet *p;
        int n;

        assert (size_ > 0);

        if (++seqno_ < maxpkts_) {
                n = nbytes / size_;
        
                if (nbytes == -1) {
                        start();
                        return;
                }
                while (n-- > 0) {
                        p = allocpkt();
                        hdr_rtp* rh = hdr_rtp::access(p);
                        rh->seqno() = seqno_;
                        target_->recv(p);
                }
                n = nbytes % size_;
                if (n > 0) {
                        p = allocpkt();
                        hdr_rtp* rh = hdr_rtp::access(p);
                        rh->seqno() = seqno_;
                        target_->recv(p);
                }
                idle();
        } else {
                finish();
                // xxx: should we deschedule the timer here? */
        };
}

void RTPAgent::sendpkt

(

)

[protected, virtual]

allocates the RTP packet that has to be sent

Definition at line 250 of file rtp.cc.

References lastpkttime_, makepkt(), and timestamp_.

Referenced by rate_change(), start(), and timeout().

{
        Packet* p = allocpkt();
        lastpkttime_ = Scheduler::instance().clock();
        timestamp_ = lastpkttime_;
        makepkt(p);
        target_->recv(p, (Handler*)0);
}

void RTPAgent::makepkt

(

Packet *

p

)

[protected, virtual]

creates the RTP packet and fills in the packet header fields

Definition at line 259 of file rtp.cc.

References hdr_rtp::access(), join_flag_, hdr_rtp::seqno(), seqno_, session_, RTPSession::srcid(), hdr_rtp::srcid(), hdr_rtp::T_epoch(), hdr_rtp::timestamp(), and timestamp_.

Referenced by sendpkt().

{
        
        hdr_rtp *rh = hdr_rtp::access(p);
        /* Fill in srcid_ and seqno */
        rh->seqno() = seqno_++;
        rh->srcid() = session_ ? session_->srcid() : 0;
        rh->timestamp()= timestamp_;
        if(join_flag_ == 1 ) {
                rh->T_epoch() = 1;
                join_flag_ = 0;
        } else rh->T_epoch() = 0;
        
        
}

void RTPAgent::rate_change

(

)

[protected]

We modify the rate in this way to get a faster reaction to the a rate change since a rate change from a very low rate to a very fast rate may take an undesireably long time if we have to wait for timeout at the old rate before we can send at the new (faster) rate.

Definition at line 235 of file rtp.cc.

References interval_, lastpkttime_, rtp_timer_, and sendpkt().

Referenced by command().

{
        rtp_timer_.force_cancel();
        
        double t = lastpkttime_ + interval_;
        
        double now = Scheduler::instance().clock();
        if ( t > now)
                rtp_timer_.resched(t - now);
        else {
                sendpkt();
                rtp_timer_.resched(interval_);
        }
}

void RTPAgent::start

(

)

[protected, virtual]

starts the RTP Agent

Definition at line 82 of file rtp.cc.

References INITIAL_TIMEOUT, interval_, join_timer_, rtp_timer_, running_, sendpkt(), session_, and RTPSession::start_timer().

Referenced by advanceby(), command(), and sendmsg().

{
        running_ = 1;
        join_timer_.resched(INITIAL_TIMEOUT);
        sendpkt();
        rtp_timer_.resched(interval_);
        if (session_) {
                session_->start_timer();
        }
}

void RTPAgent::stop

(

)

[protected, virtual]

stops the RTP Agent

Definition at line 94 of file rtp.cc.

References finish(), rtp_timer_, session_, and RTPSession::stop_timer().

Referenced by command().

{
        session_->stop_timer();
        rtp_timer_.force_cancel();
//      join_timer_.force_cansel();
        finish();
}

void RTPAgent::finish

(

)

[protected, virtual]

finish() is called when we must stop (either by request or because we're out of packets to send.

Definition at line 171 of file rtp.cc.

References running_.

Referenced by sendmsg(), and stop().

{
        running_ = 0;
        Tcl::instance().evalf("%s done", this->name());
}

---

Member Data Documentation

RTPSession* RTPAgent::session_ [protected]

Definition at line 474 of file rtp.h.

Referenced by command(), makepkt(), recv(), start(), stop(), and timeout().

double RTPAgent::lastpkttime_ [protected]

Definition at line 475 of file rtp.h.

Referenced by rate_change(), and sendpkt().

int RTPAgent::seqno_ [protected]

Definition at line 476 of file rtp.h.

Referenced by advanceby(), command(), makepkt(), RTPAgent(), and sendmsg().

int RTPAgent::running_ [protected]

Definition at line 477 of file rtp.h.

Referenced by advanceby(), finish(), join_timeout(), start(), and timeout().

int RTPAgent::random_ [protected]

Definition at line 478 of file rtp.h.

Referenced by RTPAgent(), and timeout().

int RTPAgent::maxpkts_ [protected]

Definition at line 479 of file rtp.h.

Referenced by advanceby(), RTPAgent(), and sendmsg().

double RTPAgent::interval_ [protected]

Definition at line 480 of file rtp.h.

Referenced by rate_change(), RTPAgent(), start(), and timeout().

RTPTimer RTPAgent::rtp_timer_ [protected]

Definition at line 481 of file rtp.h.

Referenced by rate_change(), start(), stop(), and timeout().

double RTPAgent::timestamp_ [protected]

Definition at line 482 of file rtp.h.

Referenced by makepkt(), RTPAgent(), and sendpkt().

JoinTimer RTPAgent::join_timer_ [protected]

Definition at line 483 of file rtp.h.

Referenced by join_timeout(), and start().

int RTPAgent::join_flag_ [protected]

Definition at line 484 of file rtp.h.

Referenced by join_timeout(), makepkt(), and RTPAgent().

---

The documentation for this class was generated from the following files:

• ns-allinone-2.30/ns-2.30/rtp/rtp.h
• ns-allinone-2.30/ns-2.30/rtp/rtp.cc