Tarik Alj wrote:
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> Date: Mon, 14 Feb 2000 19:21:40 +0100
> From: "Jose Juan Iglesias Rebollo" <[email protected]>
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> MIME-Version: 1.0
> To: [email protected]
> Subject: LAN INTERLAYER COMMUNICATION
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>
> Dear all,
>
> I'm programing a new NS MAC layer but I don't understand the way packets
> are scheduled to be deliver to the mac layer.
> I saw in ~ns/ll.cc code, the function sendDown(Packet *p) (that I
> suppose to be responsible of delivering packets to mac..., well I'm
> almost sure...):Actually to the ifq_, wich holds the queueing mecanism
ifq_ is a Queue object pointer. Let's say it's a Queue/DropTail pointer, ok?DropTail objects contain the dequeue member function. Mac layer must take a packet from that function, right? But the code of this function does not contain any s.schedule call. I know that the scheduler does, but events must be scheduled anywhen... This is my doubt: if the Mac layer gets its packets from ifq_, and LL layer schedules this way: s.schedule(downtarget_,...), where downtarget_ is supposed to be ifq_, what happens with this call to s.schedule?
And what does the scheduler do when we actually pass a NsObjec pointer as a Handler pointer? Does it take any NsObject member function by default? Is this default function recv(Packet *, Handler *)? If so, there´s no discussion since it's the action taken by design.
I need to understand the whole process if I want to know what I am doing.
Thanks.
Jose Juan.
>
> s.schedule(downtarget_, p, delay_);
>
> When we use a NsObject as a Handler, which function is considered to be
> the handler?.
>
> downtarget_ is supposed to be a Queue object, say Drop/Tail... Which
> mac function handles the dequeueing, if any? ~ns/ll.cc says:
>
> let mac decide when to take a new packet from the queue
>
> ~ns/mac-802_3.cc says:
>
> /*
> * This function gets called when packets are passed down from the
> * link layer.
> */
> void Mac802_3::recv(Packet *, Handler *)..
>
> I don't understand why and when and how thid function is called... and
> who makes the call!!The scheduler does...
>
> Thanks in advance...
>
>
> Jose Juan Iglesias Rebollo telecomunication engineer student at Escuela
> Superior de Ingenieros de Sevilla (Spain).Tarik