Subject: Re: multiple Tx queues
To: Erik E. Fair <>
From: Jason Thorpe <>
List: tech-net
Date: 01/07/2004 17:47:02
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On Jan 7, 2004, at 5:31 PM, Erik E. Fair wrote:

> So, you're suggesting a driver-specific queueing mechanism based on 
> TOS, rather than a more general packet queueing framework?

No.  I suggested using packet tags (in a generic way) to identify the 
type of service that a packet requires that the driver can use, if the 
driver supports it.

Let's look at it another way...

Right now, we can support alternate packet queueing schemes using ALTQ. 
  Ok, fine.  That allows packets to be re-ordered within the single 
ifqueue that the interface driver gets to look at.

However, the point David was making is that that's not necessarily 
sufficient.  On wireless networks, there is even bandwidth reserved 
between beacons for certain types of traffic.  Even if this is the 
first packet in the ifqueue that the driver sees, the driver still 
needs to know if it should transmit the packet in a way that will use 
that reserved bandwidth.

         -- Jason R. Thorpe <>

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