Dear all,
I am implementing a network coding protocol in ns2 currently.
I created a Droptail queue for the outgoing packets (coded packets) in my
source code.
But I don't know how to forward the packets in this Droptail queue except
the first one.
-----------
whenever the routing agent receives a native packet ( non-coded packet) from
upper layer,
it deques a packet from the droptail queue and forwards it using the
forward_data() function
as show below:
- - - - - - - -- - -- - - - - - - - - - - - - - - - - - - - -- - - -
forward_data(Packet* p) {
struct hdr_cmn* ch = HDR_CMN(p);
struct hdr_ip* ih = HDR_IP(p);
.......
.......
.......
Scheduler::instance().schedule(target_, p, 0.0);
}
}
-------------------------------------------------------------------------
So far as I know, when the MAC layer successfully transmitted a packet, it
will call the
tx_resume( ) function, which will call the *"callback_" handler* to tell the
upper layer to transmit
another data packet to MAC. This is defined in the following code:
------------------------------------------
void
Mac802_11::tx_resume()
{
......
......
......
......
} else if(callback_) {
Handler *h = callback_;
callback_ = 0;
h->handle((Event*) 0);
}
......
}
------------------------------------------------
Also, according to a tutorial of 802.11MAC in NS2 on the internet,
this *"callback_"
handler* is a callback function of the
upper level agent such as queue's resume function. Yet still, I don't
understand how this "callback_" works exactly.
And as for my case, what should I do so that I can continue to forward
packets in the Droptail queue?
I've been stuck on this for days, please help me.
Any advice will be appreciate.
Thanks in advance.
Lishu
