SfB Server – Sonus SBC SIP Trunk – No audio during calls

I have recently been troubleshooting an issue a customer had been facing since installing a SIP trunk from a UK Provider in preparation for a migration away from older ISDN circuits. In this deployment, the customer had already configured the SIP trunk and calls inbound and outbound to and from end-user assigned numbers were working fine, two-way audio, good quality and calls were staying up without any issues.

The problem was apparent, when a call was made inbound to the on premises SfB Server PSTN Dial-in access number. Whenever a call was made to these numbers, the calls would establish, but no audio was being sent from the Conferencing Auto Attendant, greeting a callee and offering meeting ID and pin entry options.

As I hadn’t configured the SIP trunk myself I did the usual checks and reviewed the configuration of:

  • Signalling groups; which were configured correctly (inbound/outbound calls were OK)
  • SIP server tables; which were all defined for both SIP provider and SfB
  • Media lists were in place, the provider used G711 and the appropriate TLS media list was in place for SfB
  • SIP profiles were configured correctly

Using the Sonus logging tool, LX, from a bird’s eye view of the call, I could see the invite being accepted, call being setup and teared down correctly:

Call flow setupThe next step for me was to review the invite, from the outside in (inbound call), firstly reviewing the SIP invite and SDP negotiation between the provider and our SBC appliance. The invite was a routable IP address in our signalling group and SIP server table (ITSP IP) coming in to our internal IP interface for this SIP trunk…

…but then looking at the SDP negotiation, I noticed that for the media endpoint being offered within the SDP (referred to as ITSP IP2 below), the SBC did not have a static route back available to it, and all traffic to this IP address would be sent to the default route, pointing to an internal gateway (and therefore no way of reaching the ITSP):

The SDP negotiation provides valuable information, from the media processing endpoint, to the codecs and capabilities of the call. For further reading, the following are good references:

The customer has decided to strictly define the endpoints presented to them by the ITSP, in the static route table using a /32 notation and therefore would need to explicitly define each of the endpoints required for communication to ensure correct routing. In this instance, an IP address had been missed but by correctly configuring the static route table in the SBC to account for this IP (ITSP IP2), we were now being presented audio for inbound calls to the conferencing service.

An important note I would like to make is that in this scenario, it is crucial to ensure that all endpoints/networks have been accounted for – I continued to work with the customer to ensure that the static routes covered all potential endpoints as there is the potential for the ITSP to failover between endpoints and therefore reintroducing the issue we have faced above!


Lync Mobile iOS Updated – 5.7.563

For those that may have not noticed, or have automatic updates configured – Microsoft have released Lync Mobile 5.7.563 to the iOS AppStore.

Unfortunately, release note list “bug fixes”, so not the most information to go on – has anyone noticed any changes?

Hopefully the new Skype for Business Mobile Client will be released sooner rather than later, considering the mobile client is a significant priority, I would have like to have seen its release, alongside side its desktop cousin.

Windows Phone is currently running at 5.9.1359.0.

Can anyone confirm Androids current version in the comments below?

Free prize (undecided) for the first person that does!


Thanks Richard for confirming the android version number (5.5.8975) – do you like chocolate? 🙂

Lync Mobile – Now Add Contacts (iOS/WP)

Now please someone correctly if I’m severely behind the times with this one, but whilst having a play around with Lync Mobile running on iOS I noticed a new section appear in my contacts list, added by as well as a notification in the contacts section;

Added by Section

Added by Section

Contact Notification

Contact Notification

I am easily pleased….

so when contacts add you to their contact list, as does the Desktop client, the mobile client now also provides you with notification. Expanding the group obviously shows you who has added you; Continue reading

*Issue* Lost Data When Migrating from Lync Server 2013 to Skype4B

Microsoft released KB on Saturday 2nd May via its FAST PUBLISH process, so clearly there is some urgency behind this patch.

So what’s the issue?

As we know, when migrating from one pool to another, to maintain scheduled conference IDs we leverage the Conference Directory structure (in addition to SQL).

Prior to KB3062801, if administrators leverage the Lync Server 2013 Management Shell to complete the conference directory move to a Skype for Business pool, there is the potential for data to be lost, which will not provide a pleasant experience to your end users.

How can you fix it?

Apply May 2015 CU Update for UC Managed API to all servers within your estate, this will allow for management of the conference directories, using Lync Server 2013 Management Shell.

Are there any workarounds?

Yes – use the Skype for Business management shell to move your conference directory – not the Lync Server 2013 Management Shell! 🙂

Skype for Business Server 2015 Server Components Released

Friday 1st May was a very good day for the Unified Communications community, particularly if you are pro-Microsoft, as Skype for Business RTM components released to MSDN/VLSC customers. Keep an eye out for a constant steady stream of new information as Microsoft Ignite is also currently underway – so a lot of information will soon be going from NDA to public domain classification – I can already see the blog posts currently in draft mode 😉

Learn Skype for Business Today!

….Well not exactly Today, but Microsoft do have an upcoming Webcast series that appears to be focussed more so towards end users and the actual usage of the Skype4B client. It appears that sessions will be repeated so do not be thrown off by 1am sessions, see below for the timetable and registration links;

Session / Registration Link Date
Get Started – Collaborating with Skype for Business (SKP005CAL) 21st April 2015 @ 4PM GMT
Go Further – Presenting and Organizing with Skype for Business (SKP006CAL) 23rd April 2015 @ 4PM GMT
Get Started – Collaborating with Skype for Business (SKP007CAL) 28th April 2015 @ 7PM GMT
Get Started – Collaborating with Skype for Business (SKP007CAL2) 29th April 2015 @ 1AM GMT
Go Further – Presenting and Organizing with Skype for Business (SKP008CAL) 30th April 2015 @ 7PM GMT
Go Further – Presenting and Organizing with Skype for Business (SKP008CAL2) 5th May 2015 @ 1AM GMT
Get Started – Collaborating with Skype for Business (SKP011CAL) 6th May 2015 @ 5PM GMT
Go Further – Presenting and Organizing with Skype for Business (SKP012CAL) 7th May 2015 @ 5PM GMT
Go Further – Presenting and Organizing with Skype for Business (SKP014CAL) 13th May 2015 @ 5PM GMT
Get Started – Collaborating with Skype for Business (SKP013CAL) 14th May 2015 @ 5PM GMT

#Skype4B Architecture Updates

My previous post provides a direct download link to the content I will be referencing in this blog post, the purpose of this post is to summarise the content whilst at the same time adding my opinion to the “improvements”.

So if you are anything like me you will be counting down the days to the upcoming #Skype4B webcasts, to which I received confirmation on my attendance for all sessions! (Lucky boy aren’t I?!).

Now for the content…

Continue reading