From: Scott M Vermillion (scott_ccie_list@it-ag.com)
Date: Sun Jan 25 2009 - 19:22:07 ARST
I think it'll become clear for you once you dig into it a bit. The answer
to your question totally depends on what you're trying to accomplish. You
have a lot of flexibility:
. Apply the policy to the tunnel interface without qos-preclassify
when you want to classify packets based on the pre-tunnel header.
. Apply the policy to the physical interface without qos-preclassify
when you want to classify packets based on the post-tunnel header. In
addition, apply the policy to the physical interface when you want to shape
or police all traffic belonging to a tunnel, and the physical interface
supports several tunnels.
. Apply the policy to a physical interface and enable
qos-preclassify on a tunnel interface when you want to classify packets
based on the pre-tunnel header.
I was also trying to find a link for you in the GRE documentation but it
seems I can't find anything anymore. Have I mentioned that I hate the new
documentation almost as much as I hate the new logo!?
From: Jason Madsen [mailto:madsen.jason@gmail.com]
Sent: Sunday, January 25, 2009 1:37 PM
To: Scott M Vermillion
Cc: Cisco certification
Subject: Re: QoS Over GRE
Thanks! Do you think I should apply hierarchical QoS to the tunnel
interface itself and then also apply the QoS preclass' to the same interface
as well? I haven't had a chance to read more about it yet. Doin' a
practice lab now and will definitely read more up on it tonight and try to
lab it up.
Thanks,
Jason
On Sun, Jan 25, 2009 at 1:34 PM, Scott M Vermillion
<scott_ccie_list@it-ag.com> wrote:
Hi Jason,
You hit the best article I've found on CCO on the topic. If I understand
you correctly, you're looking to do just LLQ for a class of traffic. The
problem with that is you need to induce "back pressure," which is
essentially artificial congestion in order for your LLQ to kick in. So to
my knowledge, you do need to do hierarchical QoS with LLQ as a child policy.
Otherwise, your logical tunnel interface never experiences congestion and
thus your LLQ doesn't do you a heck of a lot of good...
Regards,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jason Madsen
Sent: Sunday, January 25, 2009 8:50 AM
To: Cisco certification
Subject: QoS Over GRE
does anyone have any experience in doing priority-queuing over GRE tunnels?
I found an article by Cisco, but I can't say that it's all that I'm looking
for.
I don't want to do any QoS other than priority-queuing over the tunnels
unless required.
Here's the one link I found:
http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a0080
<http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a008
017405e.shtml>
17405e.shtml
...looking for more.
Jason
Blogs and organic groups at http://www.ccie.net
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