Hi:
Just to add something to Matthew's reply, be sure that you set the correct
compression method either frame relay (activated by default with auto qos voip
trust in links with 768k bandwith or less) or class based (compress header ip
rtp at desired class) .
You can't have both at the same time
hth
Date: Tue, 15 Jun 2010 05:28:59 -0500
From: ciscovoiceg...@gmail.com
To: ccie_voice@onlinestudylist.com
Subject: Re: [OSL | CCIE_Voice] QOS FRF.12 & MLPP
Kobel,
In my opinion, you should only retain the "frame-relay ip rtp
header-compression" under the frame-relay DLCI if you are asked to compress the
rtp packets. Because we're dealing with a slow-speed link, auto qos tries to
be helpful by adding in this command.
My general stance when it comes to answering the QoS lab questions is to only
configure what they ask you to setup. Using auto qos is helpful to rough-in a
configuration, but leaving in unnecessary elements does not demonstrate a
mastery of the knowledge you are being tested on. I will provide another
example:
When you type "auto qos voip" several classes will be created. One of those
classes, called something like "remark," will set DSCP values on so-called
rogue traffic masquerading as media or signaling traffic. If the question does
not ask you to perform that task, you'll want to remove the remark class.
I'm not sure if this helps, but it's my take on the subject. My guess is that
the lab would be specific whether they wanted class-based cRTP or not.
Matthew Berry
A+, CCENT, CCNA, CCNA Voice, CCVP, CCIE Voice Written
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Cisco Cert Journey Began: Jan 1, 2009
1st Lab Attempt: Aug 16, 2010
On 6/15/2010 4:23 AM, kobel wrote:
Also, after the Auto QOS generates a lot of classes etc. We do edit few things
here and there. Just wanted to confirm that is it a good practice to remove rtp
header compression?
I use to remove it always but now I am getting conflicting feedback that should
we remove it or not?
interface Serial0/2/0.1 point-to-point
bandwidth 256
frame-relay interface-dlci 301 CISCO
class AutoQoS-FR-Se0/2/0-301
auto qos voip trust
frame-relay ip rtp header-compression
I would appreciate any input in this regard.
you can configure cRTP in two ways. if the task doesn't explicitly ask for CB
cRTP, I keep auto qos config - why waste time? I'm not aware of any drawback of
this method.
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