From: Lora Ganeva (lganeva@mobiltel.bg)
Date: Thu Dec 13 2007 - 11:38:34 ART
To my opinion the mls qos trust cos will allow all packets coming from PCs to
preserve their original cos value. The port cos changes only the values of
unmarked traffic...So, i would do it with a policy-map - in case someone puts
a PC instead of the phone and this PC marks its traffic with cos of 5 , the
trust state will allow this traffic to pass unchanged.
Rgrds,
Lora
________________________________
From: nobody@groupstudy.com on behalf of Scott Morris
Sent: Thu 12/13/2007 2:39 PM
To: 'Darren Johnson'; 'nhatphuc'; 'Cisco certification'
Subject: RE: Trust VoIP and remark Data
I'd also adjust your mls qos cos-dscp map then. The default will read cos 5
and remap the dscp to 40 instead of 46.
:)
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
A Cisco Learning Partner - We Accept Learning Credits!
Telephone: +1.810.326.1444
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-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Darren Johnson
Sent: Thursday, December 13, 2007 6:46 AM
To: 'nhatphuc'; 'Cisco certification'
Subject: RE: Trust VoIP and remark Data
Hey there! I believe your second option is wrong, you don't need the
override and you need to trust cos. I would do it like this....
mls qos trust device cisco-phone
mls qos trust cos
mls qos cos 1
This says trust the COS value ONLY if a Cisco phone is detected via CDP, and
any packets/frames without a COS value (such as those received from a PC on
the native vlan) use a COS value of 1. The COS override would 'override' any
COS values to 1, including COS values received from the phone!! I don't
believe you want to do this!
Dazzler
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
nhatphuc
Sent: 12 December 2007 17:55
To: Cisco certification
Subject: Trust VoIP and remark Data
Hi Group,
With question: Ensure that VoIP traffic originating from the IP phones
maintains its CoS value, while traffic originating from the PCs is remarked
with a CoS of 1
I see 2 ways to answer. The first seems to be better, but I don't see
anything wrong with the second. Which one do you choose? Please explain.
mls qos trust cos
switchport priority extend cos 1
and
mls qos trust device cisco-phone
mls qos cos 1 override
Thank you
Phuc
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