Part 2 - SBA-Survivable Branch Appliance

Great concept, terrible name - keep thinking of a toaster.

Stop reading and start seeing the animated tutorial - click here!

Here are some of the basic calling options using an SBA in a BO and HQ:

1 - Normal mode - BO users register with Primary SBA Registrar

2 - SBA is down - BO users register with Secondary HQ - Intra-Inter BO calling managed by HQ

3 - Mobile/remote users register with HQ Primary Registrar to calls to BO

4 - Mobile/remote users register with HQ Primary Registrar to calls to HQ

5 - WAN is down - BO users register with Primary Registrar to call to HQ or anyone

6 - PSTN replaced with SIP Trunk provider for calls to PSTN and other SIP endpoints

Please refer to the animation for details.

SBA-Survivable Branch Appliance aka Stand Alone Survivability (SAS)

Editor Note: This is an introduction, not an indepth analysis.  In the animated tutorial, there are some examples of BO-Branch Office configurations along with tutorials on HSRP-Hot Standby Routing Protocol, QSIG, MPLS and other related topics. 

In addition, as a user/VAR, an indepth assessment of the critical features is required for each type BO configuration before implementation.  AudioCodes, NET, Dialogic, Cisco and others all have excellent systems. However, I would like to thank NET for their help in preparation of this presentation.  If you have a SBA or any other Lync product or solution you want covered, please let us know.

This is a partial list of SBA features.  Check with manufacturer offerings for specific features, not listed in order of importance:

Interfaces

- TDM-Time Division Multiplexing - CAS-Channel Associated Signaling for both voice and data traffic:

     E1-European - 2.048 MPS-Megabits Per Second

     T1-Transmission Level One - 1.1544 MPS

 - ISDN-Integrated Services Digital Network

     PRI-Primate Rate Interface used for voice traffic only

- Concurrent voice call support - assumption is 80 Kbytes per G.711 call, e.g. 30 calls per T1 using lower bit rate G.729 (rollover CODEC for more)

- Load-balancing to mitigate traffic

- Video, webconference, multi-media, multi-party QoS

- FXO-FXS - Foreign eXchange Office/Service for analog devices including FAX there is a tutorial on FXO/FXS in the animated tutorial

- RTP and sRTP-secure Realtime Transport Protocol

- Investment Protection for legacy telephony equipment

- Scaling "pay-as-you-grow"  modular architecture

- Connecting the Microsoft UC environment to branch office PBX and PSTN

One Last Replay - Avoid Asynchronous Transcoding

Transcoding and multiple- transcodings explained.

Click here for animated tutorial (requires Flash).

However, Asynchronous Transcoding is to be avoided.  According to Intel, "The term "asynchronous transcoding" refers to a situation when, for example, one endpoint is talking G.711 to another endpoint talking G.723 (two different encodings)."

The result of Asynchronous Transcoding is the delay, distortion and resultant much lower QoS.  As you can see (only in the animation), different CODEC-COmpression-DECompression DSP-Digital Signal Processing device sampling rates such as G.711 and G.729 may start synchronized but shortly become un-synchronized which can cause encoding problems and voice to jitter.  To measure and manage jitter RTP-Realtime Transport Protocol uses the time-stamp function in the protocol to assess jitter based on the delay between arrival (interarrival) times of each packet.  Changing the number of bits sampled and quantized can dramatically impact the voice quality.

Click here for animated tutorial (requires Flash).

Here is the QoS for two commonly-used CODECs:

- G.711 µ-law - 64 KBPS - "Toll Quality" voice 

- G.723.1 - 5.3/6.3 KBPS - low quality and more CPU processing

Microsoft uses RTAudio Lync Communications is deployed.  G.711 and G.723.1 are the CODECs used for Exchange Voice Mail.  Note:  This is like anything else is subject to change without notice in new versions of Lync and Exchange.  In other words, the inbound stream for calls placed by using Play on Phone will use the G.711 or G.723.1 codec. RTAudio processing by a Unified Messaging server consumes more CPU cycles than any of the other CODECs but can be turned off.

Here is an example of a High performance mediation platform for UC & Enterprise SBC, qualified for Office Communications Server (OCS) R2 and Lync Server 2010 from NET (click here for website).

30 facts and information about Lync which are totally new and different than OCS, here's the first ten. 

For the complete MS Technet blog list, click here:

1. Lync introduced 'Survivable Branch Appliance', which is a new device introduced in Lync Server 2010 that combines a PSTN gateway with a Lync Server Registrar and Mediation Server. This appliance is targeting br

1. You can virtualize all topologies and we support all workloads, including Enterprise Voice to be virtualized.  When you virtualize, Scalability is roughly 50% of the scalability offered by a Lync Server 2010 topology running only on physical servers.
2. anch offices that require telephony services in case of WAN failures with the central site. In the event a branch office's WAN connection to a data center fails, the Survivable Branch Appliance provides the following voice features to users in that branch office:

• PSTN inbound and outbound calls
• Intra-site and inter-site calls
• Call hold, retrieve, and transfer
• User authentication and authorization
• Leaving and retrieving voicemail
• Call forwarding, simultaneous ringing, boss-administrator, and team calling
• Call Detail Recording (CDR).
• All two-party functionality, including instant messaging and audio-video conferencing
• PSTN dial-in conferencing with Conferencing Auto-Attendant

3. Microsoft Lync Server 2010 introduces DNS load balancing for load balancing for SIP and media traffic (you will still need hardware LB for other traffic such as HTTP however this is the easiest part in configuring a HW load balancer). DNS load balancing is supported for Front End pools, Edge Server pools, Mediation Server pools, and Director pool.
4. Microsoft Lync 2010 Attendee is a new downloadable client that enables users without Microsoft Lync 2010 to attend meetings
5. You manage Edge Servers from the internal network. All configuration data for servers and services resides in the Central Management database, which you can manage by using internal administrative tools
6. Lync Server 2010 introduces support for integration with hosted Exchange UM
7. Lync supports Enhanced 9-1-1 (E9-1-1) as part of your Enterprise Voice deployment
8. Malicious call tracing enables users to flag incoming calls which are harassing, threatening, or obscene. Immediately after hanging up, the user can select an option to report the call as malicious. If they do so, a trace request is sent to mark the record of the call, and an event is logged
9. Lync 2010 clients can now receive updated software from Windows Server Update Service (WSUS) or Microsoft Update instead of from a location hosted on Lync Server 2010
10. Lync Server 2010 provides support for analog devices. Specifically, the supported analog devices are analog audio phone and analog fax machines. Now you can configure the analog gateways and devices in your organization to use Lync Server 2010. After you do this, analog devices use Lync Server to make and receive calls, and Lync Server makes routing decisions and log calls in call detail records (CDRs) for analog devices, just as it does for any device

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