[e2e] Is RED dead?

[John Kristoff]

On Mon, 19 Sep 2005 11:58:50 -0500
John Kristoff <jtk at northwestern.edu> wrote:

> I've recently been told by a trusted and clueful colleague that RED
> is a "compromised concept" and a "dead horse".  That surprised me a
> bit and I've been trying to understand why.  I've been reading and
[...]

I told a couple folks I would follow up with what I heard and learned
off list.  I heard from one person that thought RED.  Off list I heard
that a couple of big providers may use it when links become congested,
and that they will enable it if you ask, but do not by default.

Someone pointed out this useful link containing an extensive evaluation
of AQM schemes:

  <http://www.cs.unc.edu/~le/>

In my own experience with some Cisco gear, I suspect a fair number of
people have WRED on a number of interfaces where they have turned on
the QoS knobs for the box, primarily it seems as part of a VoIP
roll-out.  The queueing mechanisms are hardware dependent, but on a
Cisco 6509 Catalyst for example, most modern hardware modules come
with WRED on by default when you turn on 'QoS'.  However, since this
deployment is probably often done within campus networks where
congestion is rare, AQM is probably rarely activated.

In addition, in at least one Cisco platform I'm familiar with (6509/720
running native IOS), you also get the QoS knobs and WRED queueing turned
on by default when you enable Cisco's Control Plane Policing services.
I know of at least one large provider who is using this feature and I
suspect they've got some WRED queues without even knowing it.

So... in a nutshell, I feel I had gotten a very weak response to this
question.  Most people just don't seem to care enough or have problems
that really require it to be interested enough in RED or related
mechanisms at this time, but I wasn't convinced it was a compromised
concept.  :-)

John