Re: [ns] drop-tail. a misnomer?

[Lloyd Wood <l.wood@eim.surrey.ac.uk>]

On Fri, 21 Sep 2001, jmentz wrote:

> Hi, I am wondering why drop-tail queues are so named.  To me this name
> suggests that such queues implement partial packet discard on
> overflow. 

partial packet discard is an ATM-specific concept (your question is
understandable given Cape Town's exclusive focus on ATM - well, over
in the EE comms group, anyway. But there's more to networking than
ATM.)

> The following code taken from the manual demonstrates that the
> entire arriving packet is discarded.

that's correct. Packets are dropped from the tail of the _queue_ of
packets, hence drop-tail.

totsiens,

L.

> void DropTail::enque(Packet* p)
> 	{
> 	q_.enque(p);
> 	if (q_.length() >= qlim_) {
> 		q_.remove(p);
> 		drop(p);
> 		}
> 	}

<L.Wood@surrey.ac.uk>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>