964| Voice and Video AOS-W 6.5.3.x| User Guide
Verify the RTP analysis for an active call by issuing the following command:
(host)#show voice real-time-analysis
While a Lync/Skype for Business call is active, the output of this command displays the current delay, jitter,
packet loss, and UCC score of the client. This command displays any data only if the client is on an active call.
UCC Limitations
n Voice ALGs should not be enabled when voice clients are behind a NAT.
n Media classification does not work when user VLAN has IP NAT configured.
n When using media classification, UCC score, jitter, delay, and packet loss is calculated only for voice RTP
streams. These metrics are not available for video streams.
n Media classification does not work in split-tunnel forwarding mode.
n When VoIP calls are prioritized using media classification, end-to-end call quality metrics such as Mean
Opinion Score (MOS), delay, jitter, and packet loss are not available.
n UCC score is calculated for voice calls and desktop-sharing sessions only.
n For Lync/Skype for Business calls, MOS is generated only for voice calls. Lync/Skype for Business server
does not generate MOS for video calls, desktop-sharing, and file-transfer sessions.
n When SIP messages are sent over UDP and the packet size is large such that it gets IP fragmented, the
switch does not prioritize SIP ALG or provide any visibility to such calls.
n A client device may run multiple UCC applications such as SIP and Skype for Business. AOS-W 6.x supports
only one UCC application per client device. AOS-W provides firewall, prioritization, and visibility services for
media sessions belonging to the UCC application that was registered first using the client device.
Understanding Extended Voice and Video Features
This section describes the other voice and video-related functionalities that are available on the switch.
Understanding QoS for Microsoft® Lync/Skype for Business and Apple FaceTime
Voice and video devices use a signaling protocol to establish, control, and terminate voice and video calls. These
control or signaling sessions are usually permitted using pre-defined ACLs. If, however, the control signaling
packets are encrypted, the switch cannot determine which dynamic ports are used for voice or video traffic. In
these cases, the switch has to use an ACL with the classify-media option enabled to identify the voice or video
flow based on a deep packet inspection and analysis of the actual traffic.
Microsoft® Lync/Skype for Business
Lync and Skype for Business (Skype4b) uses SIPS to establish, control, and terminate voice and video calls. The
following example creates an ACL named skype4b acl for Skype4b traffic that identifies port 5061 as the
reserved SIP-TLS port.
(host) (config) #ip access-list session skype4b-acl
(host) (config-sess-skype4b-acl)#any any tcp 5061 permit position 1 queue high classify-media
(host) (config-sess-skyper4b-acl)#any any udp 1025-65535 permit position 2 queue low
UCC Score for Lync/Skype4b Media Classification
The switch supports UCC score for Lync/Skype4b calls prioritized using media classification. As part of this
feature, Unified Communication Manager (UCM)supports the following:
n Real-time quality analysis for Lync/Skype4b voice and video calls (voice RTP streams only)
n Real-time computation of UCC score (delay, jitter, and packet loss) for Lync/Skype4b VoIP calls prioritized
using media classification. The UCC score is computed by the AP in the downstream direction.
To Next Page
Loading...