QoS for Cisco Router to Prioritize Voice and Interactive Traffic
- by TJ Huffington
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
    fair-queue
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 1.2.3.4 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.