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I have a Cisco 891W NATing Voice and Data to the internet over a 10mbit/2mbit connection. Voice traffic gets degraded when I upload large files. Pings time out as well.

I tried to configure a QoS policy but it's basically not doing anything. Voice traffic still degrades when upload bandwidth gets saturated.

Here is my current configruation:

class-map match-any QoS-Transactional
 match protocol ssh
 match protocol xwindows
class-map match-any QoS-Voice
 match protocol rtp audio
class-map match-any QoS-Bulk
 match protocol secure-nntp
 match protocol smtp
 match protocol tftp
 match protocol ftp
class-map match-any QoS-Management
 match protocol snmp
 match protocol dns
 match protocol secure-imap
class-map match-any QoS-Inter-Video
 match protocol rtp video
class-map match-any QoS-Voice-Control
 match access-group name Voice-Control

policy-map QoS-Priority-Output
 class QoS-Voice
    priority percent 25
  set dscp ef
 class QoS-Inter-Video
    bandwidth remaining percent 10
  set dscp af41
 class QoS-Transactional
    bandwidth remaining percent 25
     random-detect dscp-based
  set dscp af21
 class QoS-Bulk
    bandwidth remaining percent 5
     random-detect dscp-based
  set dscp af11
 class QoS-Management
    bandwidth remaining percent 1
  set dscp cs2
 class QoS-Voice-Control
    priority percent 5
  set dscp ef
 class class-default

interface FastEthernet8
 bandwidth 1024
 bandwidth receive 20480
 ip address dhcp
 ip nat outside
 ip virtual-reassembly
 duplex auto
 speed auto
 auto discovery qos
 crypto map mymap
 max-reserved-bandwidth 80
 service-policy output QoS-Priority-Output

crypto map mymap 10 ipsec-isakmp
 set peer default
 set transform-set ESP-3DES-SHA
 match address 110
 qos pre-classify

fa8 is my connection to the internet. Voice traffic goes over a VPN ("mymap") to the SIP server. That's why I specified "qos pre-classify" which I believe is the way to classify traffic over the VPN. However even when I ping a public IP while saturating upload bandwidth, the latency is exceptionally high.

Is this configuration correct? Are there any suggestions that might make this work for my setup?

Thanks in advance.

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If you do a show policy-map interface Fa8, you should see how the different QoS classes are being utilized. If you're seeing anything in the priority class, I'd say that qos pre-qualify is doing its work.

share|improve this answer

I’m not a Cisco expert, but our supposed experts left us with a similar problem: QoS configured but doing nothing. The solution turned out to be painfully simple, though it took me a very long time to find it. Run the following command:

show mls qos interface

In our case, the result was:

QoS is disabled. pass-through mode
When QoS is enabled, following settings will be applied…

Our switches finally started doing what we bought them for when I ran the following command:

mls qos

Apologies if this was too obvious to mention; I hope it may help someone else who’s Googling for the problem.

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