Re: [ns] Problems with mobile libraries: Interface queue exists?

[Satish Kumar <kkumar@isi.edu>]

downtarget_ of the ll class is initialized to point to the interface queue by 
the add-interface tcl instproc (in ns-2/tcl/lib/ns-mobilenode.tcl). Packets 
are put on the ifq by the LL sendDown method.

Satish


> Hello NS users,
> 
> I'm simulating a wired+wireless scenario and I would like to monitor the
> interface queue length.
> 
> I have been looking for the interface queue in the code
> (ll{.cc,.h,arp{.cc,.h},mac-802_11{.cc,.h}) trying to found how I can
> access to its value, but what I have found is that in ll.h an ifq_
> variable is defined but is never used.
> 
> NS documentation says :'The network stack for a mobilenode consists of a
> link layer, an ARP module connected to the LL, an interface priority
> queue(ifq), a MAC layer, a network inteface(netIF), all connected to the
> channel.' p 122
> 
> and 'Once the hardware address of a packet's next hop is known, the
> packet is inserted into the interface queue' p 123
> 
> All what I have been found is that when the hardware address is known
> ARP schedules the packet directly to the scheduler, without using any
> inteface queue.
> 
> Moreover I've tried to get access to the LL ifq_ variable and what I've
> found is that is always NULL.
> 
> I would like to know if the implementation is wrong or if I have to use
> another kind of LL (I've tried with Snoop but it doesn't work with
> wireless).
> And for what is supposed to be used the ifqlen and things like that in
> the .tcl file if after it's not used anywhere.
> 
> Thanks in advance,
> 
> Xavi