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Can you provide more details around whether or not I need to deploy a Survivable Branch Appliance for my Lync deployment?

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This question was asked by a college based out of Florida looking to deploy Lync for their 1500 faculty and staff.  They had redundant WAN links and wanted to determine what a SBA provides. Screenshots from Lync product team.

If I have redundant WAN links, what benefits does a SBA provide for my branch offices?

An SBA provides the following benefits:

  • Local SIP Registrar – don’t have to carry this over the WAN
  • Normal/Failover mode – WAN primary and PSTN as backup for failover
  • SIP Proxy & Routing engine
  • PSTN connectivity
  • Voicemail routing
  • PSTN re-routing – auto re-route to PSTN during WAN failure and auto failback when WAN is restored
  • Centrally provisioned
  • Call Detail Records
  • Replicated CMS
  • Branch office users hosted on SBA
  • Up to 1000 user support

 

What are my Branch Office options for Lync Server?

You have three recommended options available to you.The first is no SBA for 25 users or less.  The second is an SBA for 26-1000 users and the third option for 1001-5000 users is a Survivable Branch Server or Lync Std Edition Server with a Media Gateway. For remote sites with more than 5000 users it is recommended to deploy a full Lync infrastructure with a separate pool.

The idea here is you could use WAN as your primary and have a fallback for PSTN for high availability. For the small branch scenario, some UC phones allow for dual registration where you could fall back to an alternate VOIP provider is need be.

 

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Does an SBA provide inbound and outbound dialing during a WAN failure?

End user experience when using failover to PSTN.

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The answer is yes. Here are the features that work during resiliency mode in the branch office:

  • PSTN Inbound and Outbound calls
  • Intra-Site calls, Inter site calls (PSTN Rerouting)
  • Hold, Retrieve, Transfer
  • Authentication, Authorization
  • Voicemail Deposit (Redirect to ExUM in Data Center)
  • Voicemail Retrieve (through PSTN)
  • Call Forwarding, SimulRing, Boss-Admin, Team-call
  • Call Detail Records (CDR)
  • All 2 Party Intra Site communications
  • Audio Conferencing through PSTN
  • Contact Search

What are the Lync features which don’t working during a WAN outage in the branch office?

  • Inter-site Data (IM, App Sharing, etc.)
  • Conferencing (IM, Video and Web)
  • Presence & DND based routing
  • Modify Presence or Change Call Forwarding Settings
  • Contact List
  • Response Group and Call Park

Who are the SBA partners available for Lync Server 2010?

  • AudioCodes
  • HP
  • Dialogic
  • NET
  • Ferrari

How do I deploy a SBA?

I put together a summary of the required steps. For more specific details visit here.

  • Pre-create a computer account (for the SBA) in the branch office.
  • SBA is added to the Lync Server 2010 Topology via Topology designer. These are the only steps which had to happen before the SBA can be deployed in the branch.
  • SBA gets dropped from the vendor to the branch with preinstalled software. The local administrator connects to the device via webinterface and configure the IP address, so that the SBA is reachable and he connects the SBA to the domain. After the IP configuration the ISDN connection to the PBX has to happen.
  • SBA receives the configuration information from the centralized store. Now the certificates had to be assigned to the SBA, afterwards the administrator can start the services.
  • Lync Server 2010 administrator moves the User from the local pool to the SBA.

How can I provide redundant Response Group Service with Lync if my primary datacenter fails?

If you stretch your Lync pool across datacenters you can accommodate this.

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Comments

  • Anonymous
    January 01, 2003
    Sergey, IM, Video and web conferencing does not work during resiliency mode. Lync PSTN audio conference bridge continues to work since you are using PSTN lines rather than WAN for dial tone.  The number of users in the branch office that can use this depends on the type of PSTN link provisioned.

  • Anonymous
    January 01, 2003
    Mark, You would want to configure Lync to be highly available in the local datacenter to prevent single point of failure. You can also configure Lync to failover to an alternate datacenter using a backup SIP registrar. This would be a recommended approach over an SBA (used mainly for branch offices, etc). See here for more info: technet.microsoft.com/.../gg398347.aspx

  • Anonymous
    January 01, 2003
    Andrew, Response groups would not work during a WAN outage but would work when the WAN is available.

  • Anonymous
    January 01, 2003
    Chris, For 25 users or less, you can still deploy an SBA or you could leverage a UC SIP phone which has the ability to insert dual SIP providers such as snom. I have a snom sample phone where I can dual path to Lync and my local VOIP provider.

  • Anonymous
    December 03, 2010
    For smaller branches, are you saying there's no affordable way to provide redundancy in the event of internet loss?

  • Anonymous
    March 30, 2011
    How many users can participate in the conference during resiliency mode in the branch office? Or maybe no limits?

  • Anonymous
    September 09, 2011
    Thanks for this article, very good. Please tell me, if I put a SBA live, am i am able to take inbound calls on the PSTN and process them through a response group as the default behaviour?

  • Anonymous
    September 27, 2011
    Could this be used for a primary site where the Lync server became unavailable?  We have a municipal fire department that is the backup command center in the event of an emergency.  They want to use Lync for their Enterprise voice but it would be 12 phones on an average day and perhaps 50 in an emergency situation. They want to know that the failure of the Lync server would not prevent them from making calls, so I'm curious if an SBA at the primary (or only) site might be a viable option.