Subject: Re: multiple Tx queues
To: Greg Troxel , David Young <>
From: Sam Leffler <>
List: tech-net
Date: 01/10/2004 19:15:53
On Saturday 10 January 2004 12:46 pm, Greg Troxel wrote:
> Or are you talking about cards that have multiple queues, where each
> queue is associated with a link-layer priority scheme (perhaps that
> even extends across switches, e.g vlan-like qos tags - I'm not clear
> on the standards here).

The Atheros 5212-based cards support multiple xmit queues and implement a 
variety of queueing policies in h/w.  This stuff is explicitly intended to 
supoprt QoS as set out, for example, the WME spec.  Applications include VoIP 
and streaming video.  To effectively use this stuff applications need to be 
able to tag packets and have the OS stay out of the way except to not smash 
the tag before it reaches the driver (where it can be used to select the 
appropriate queue).