Troubleshooting and limitations with Lync / Skype for Business and Pexip Infinity integrations

Lync client does not connect to Pexip Infinity conference

Checklist

• Verify that a Virtual Meeting Room with the alias being dialed exists on the Management Node.
• Verify that the Conferencing Node receives the SIP INVITE request from the Lync client (via the FEP):
  • Management Node support log (Status > Support log)
  • Lync FEP logging tool

Detail

If the Lync client fails to connect to the conference altogether, we need to verify that the alias exists on the Management Node. After that has been verified, check if the Conferencing Node receives the SIP INVITE request from the Lync client. This can be done both on the Conferencing Node (with the support log) and on the FEP serving the Lync client (using the Lync debugging tools.

A normal SIP call flow between a Lync client and the Pexip Infinity Conferencing Node should be:

Lync client		Pexip Infinity
	INVITE (with SDP) --->
	<--- 100 TRYING
	<--- 180 RINGING
	<--- 200 OK (with SDP)
	ACK --->

After ICE negotiation has completed between the Lync client and the Conferencing Node, the Lync client should send a second INVITE to signal the ICE negotiation completion. If this second INVITE is not seen, this is a strong indication of a media connectivity issue between the two peers.

Lync client can successfully connect to the Pexip Infinity conference, but audio and/or video is not working in one or both directions

Checklist

• Verify that the Lync client is correctly configured with an audio and video device.
• Verify that the call from the Lync client is placed as a video call rather than a Lync (audio-only) call.
• Verify (with SIP logs) that the SIP call setup behaves as expected:
  • INVITE from Lync client should contain m=audio and m=video lines in SDP
  • 200 OK response from Pexip Infinity should contain m=audio and m=video lines in SDP.
• Verify that firewall configuration permits relevant media traffic.
• Verify that Lync client receives RTP media from Pexip Infinity (using for instance Wireshark).
• Verify that Pexip Infinity Conferencing Node receives RTP media from Lync client (using for instance tcpdump).

Collecting SIP logs using the Lync Server Logging Tool

The Microsoft Debugging Tools can be downloaded from:

• Lync Server 2013: http://www.microsoft.com/en-us/download/details.aspx?id=35453
• Skype for Business Server 2015: https://www.microsoft.com/en-us/download/details.aspx?id=47263

The default location for installation of the logging tool is:

• Lync 2013: C:\Program Files\Microsoft Lync Server 2013\Debugging Tools\OCSLogger.exe;
• Lync 2010: C:\Program Files\Common Files\Microsoft Lync Server 2010\Tracing\OCSLogger.exe
• Skype for Business Server 2015: C:\Program Files\Skype for Business Server 2015\Debugging Tools\CLSLogger.exe

Note however that a different location may have been chosen at the time of installation.

After opening the logging tool, the following selection is normally suitable for initial troubleshooting of failing calls between Lync and the Pexip Infinity Conferencing Node:

• Components: SIPStack, InboundRouting and OutboundRouting

  (Note that the InboundRouting and OutboundRouting components are only available on a FEP)

• Level: Information
• Flags: All Flags

To use the Lync Server logging tool:

1. Select Start Logging and place a new call from the Lync client towards the Pexip Infinity conference alias.
2. After the call has failed, select Stop Logging.
3. Select View Log Files.
4. Select View in the dialog which appears, and save the resulting text file in a suitable location.

Conference status shows backplanes to a merged AVMCU conference with no participants

After a Pexip VMR has been merged with an AVMCU conference, when viewing the conference status information for the VMR you may see one or more backplanes to the AVMCU where there are no participants connected to that AVMCU node. One way in which this can occur is if a Lync client dials into a Pexip VMR, invites other Lync contacts into the meeting and then all of those participants disconnect.

Whenever a Lync client that is dialed into a Pexip VMR adds a contact into the meeting, an adhoc AVMCU conference is created and it is merged with the Pexip VMR. A backplane is established between the AVMCU conference and the Pexip VMR. That backplane will continue to exist even if all of the participants in the AVMCU conference disconnect. The backplane is only taken down when the Pexip VMR conference ends.

Therefore if the Lync client and any other Lync contacts that had been in the adhoc AVMCU conference all disconnect, you will continue to see the merged AVMCU conference as a remote media node but with no participants connected to it.

Note that the remote media node of a merged AVMCU conference is identified by the address of the Lync client that initiated the AVMCU conference.

Poor image quality and delays when sharing content from Lync

This can occur when the maximum inbound or outbound call bandwidth is too low.

Ensure that the Maximum inbound call bandwidth and Maximum outbound call bandwidth advanced configuration settings for the Virtual Meeting Room or Virtual Auditorium is at least 1024 kbps.

DNS resolution failures

The following error messages indicate that DNS is not resolving addresses correctly:

• Transaction failed UPDATE appears as the disconnect reason when viewing participant status
• RFC3263 lookup failure appears in a support.dns log entry in the support log

Sending messages from a Lync client to a locked conference

If a Lync client initiates an IM session with a locked Pexip Infinity conference and attempts to send a message, it will appear to the Lync client as though the message has been successfully sent.

However, other participants in the Pexip Infinity conference will not see the message. The Lync client will temporarily appear in the conference participant list but cannot be allowed in to the locked conference (as they are not currently sending any audio or video).

Lync participants do not receive presentations / content sharing

This can occur if Pexip Infinity is not configured to enable outbound calling to Lync clients.

Configure Pexip Infinity to enable outbound calls to Lync clients. This includes ensuring that every Conferencing Node is configured with a TLS server certificate that is trusted by the Lync server environment, and that every node has its unique SIP TLS FQDN setting configured. See Certificate creation and requirements for Lync / Skype for Business integrations for more information.

Video calls from a Lync 2010 client for iOS only connect with audio

Outbound video calls made from the Lync 2010 client for iOS may only connect using audio rather than automatically escalating to video as expected. This is currently the expected behavior with this type of Lync client.

Lync presenter sees "Someone has joined and can't see what's being presented or shared" notification

If a Lync participant in an AVMCU multi-party conference is presenting while another device joins the AVMCU conference via the Pexip Distributed Gateway, the Lync presenter will see a "Someone has joined and can't see what's being presented or shared" notification.

However, the gateway participant will be able to see the presentation. The notification will disappear after approximately 15 seconds.

Lync users see low-resolution presentations in small scale

If a standards-based endpoint transmits a dual stream presentation at a very low resolution, the transcoded presentation will be sent in native resolution to any connected Lync clients.

This may create a sub-optimal experience depending on the PC screen resolution of the Lync end-user PC.

Can only make audio calls when using a Cisco VCS for call control

If a Cisco VCS is used as call control between a Conferencing Node and a Lync 2013 FEP, only audio calls are possible.

The FEP and the Conferencing Nodes should be neighbored directly and then audio and video calls will work as expected.

No video on Lync for Mac or Lync 2010 (PC) in AVMCU conferences

Video from Lync 2010 or Lync for Mac clients will not be seen on endpoints connected via Pexip into AVMCU conferences.

Pexip Infinity does not currently support sending an RTV video stream into AVMCU hosted conferences. As a result, video from clients that only support RTV (such as Lync 2010 and Lync for Mac) will not be visible to those endpoints.

However, clients such as Lync for iPhone, Android, Lync 2013 PC, Windows phone, Skype for Business 2015 and so on, all support video when connected via Pexip into AVMCU conferences.

Poor sound quality

AVMCU calls support a maximum of G.722 (7 KHz audio), while Pexip Infinity supports up to AAC-LD (48 KHz audio). Under certain circumstances (for example, a meeting room with poor acoustics and many people speaking) there may be a perceptible difference in sound quality between an endpoint when using G.722 and the same endpoint when able to use a wider-band codec.

Problems connecting to AVMCU conferences via the Virtual Reception (IVR gateway)

The following table describes the typical problems and suggested resolutions for issues related to connecting to AVMCU conferences via the Virtual Reception (IVR gateway).

Symptom	Possible cause	Resolution
After entering the Conference ID, the call tries to connect to the user that scheduled the meeting.	The relevant Call Routing Rule does not have Match against full alias URI selected.	Ensure that Match against full alias URI is selected.
After entering the Conference ID, you get a "Call Failed: Conference extension not found” error.	The relevant Call Routing Rule does not have a trailing .* in the Destination alias regex match field.	Ensure that the Destination alias regex match field has a trailing .*

For more information, see Routing indirectly via a Virtual Reception (IVR gateway).