What's exactly going on when a packet is received at a node?

[Urs Thuermann <thuerman@ibr.cs.tu-bs.de>]

I'd like to know, what's going on when a packet is received at a
node before it is forwarded to the outgoing link's Queue object by
invoking Queue::enque(p).

I assume that there is at least some object that does the routing
decision and then calls Queue::enque(p) for the selected queue or that
passes the packet to some other object that finally calls
Queue::enque().

Is this correct, and if so, what is the chain of objects and functions
involved in passing a packet through the node?  And can I put
something inbetween this chain?

I'd like to process some of the packet header's fields before it is
sent to the outgoing queue.

What source files of ns-2 should I read?


urs