By default Cisco WebEx traffic do not mark voice and video packet natively like other VOIP clients and use HTTPS protocol for communication. WebEx voice and video traffic needs to be prioritized on internal network over other network traffic such as FTP, HTTP till the time it reach your local/central Internet exit points.
Outgoing WebEx QOS Policy –
Outgoing WebEx Voice and Video packets towards to Internet should be marked as AF42 with help of Window GPO policy .
The behavior of the WebEx desktop client is that it will perform a test to attempt connection on UDP 9000 for voice and video traffic. If this port is closed the connection will fallback to TCP which will go through your company proxy system.
Using TCP in a near congested network will cause re transmissions, which in turn can create a choppy video or low bandwidth error experience. UDP does not re transmit, which is why it will provide a better voice/video experience.
For better WebEx voice and video quality, you should open UDP port 9000 on your company firewalls towards to WebEx data centers and vise -versa globally.
Below sample GPO policy will mark all the WebEx voice and video traffic on UDP port 9000 as AF42 which will be trusted on your company LAN/WAN/Wireless/Internet Edge routers till the time it reach the Internet.
Application Name – Atmgr.exe
Protcol – UDP
Source Port – *
Destination Port – 9000
DSCP Value – 36
Please note, you can not differentiate voice and video traffic from WebEx traffic so we should use single AF42 QOS marking for WebEx media traffic.
Incoming WebEx QOS Policy –
Incoming WebEx Voice and Video packets from Internet to your company network should be marked as AF42 with help of ACL policy on Internet Edge routers.
WebEx Cloud data center sends voice and video traffic with source port as UDP 9000 so we can implement ACL rule at all your company Internet Edge routers to mark WebEx incoming voice and video traffic as AF42.
Below is sample configuration for your reference purpose.
ip access-list extended QOS_WebEx_QOS
permit udp any eq CISCO_WEBEXIPs 9000 any
class-map match-any WebEx
match access-group name QOS_WebEx_QOS
policy-map INGRESS_MARKING
class WebEx
set dscp Af42
This section applies the policy-map to the Internet Edge interface.
Router (config-if)# service-policy input INGRESS-MARKING