[ns] Introduce delay in passing packet to Link Layer

[Kok Lim, Yau]

Hi All,
 
The recv function in link layer (mac/ll.cc) receives packet from routing agent using the following command:
 
ll->recv(p,(Handler *)0);
 
where ll is defined as the link layer.
 
The above command does not has delay. How to introduce delay in passing a packet to the ll layer?
 
Thanks in advance!
 
Regards,
KL