ACANO SOLUTION
ACANO SOLUTION
MICROSOFT LYNC INTEGRATION ARCHITECTURE A White Paper by Mark Blake, Acano CTO
June 2014
Contents
CONTENTS Introduction ....................................................................................................................... 3
Key Features of the Acano Lync Integration ............................................................ 3
How It Works ..................................................................................................................... 4
Basic Architecture............................................................................................................ 4
Starting Simple: Transparent Gateway for Point-to-Point Calls to SIP ............... 5
Point-to-Point Calls to an Acano Client or WebRTC ............................................... 6
Dealing with Media.......................................................................................................... 7
How a Call is Made – Directory Integration.............................................................. 8
Dealing with Real Network Conditions ...................................................................... 8
Access for any Lync User – Lync Edge Support ..................................................... 9
Direct Federation with Lync .......................................................................................... 9
Integration with Skype.................................................................................................. 10
Call Escalation..................................................................................................................12
Getting Interesting – Multipoint Calls ........................................................................13
Mixed Multipoint Calls – Who Hosts the Conferencing?......................................16
SIP is the best! Do the conferencing in the SIP environment .........................16
Lync is the best! Do the conferencing in the Lync environment ...................17
The Acano solution – best of both ........................................................................18
Is Anybody There? Presence Support ......................................................................19
Unified Communications – Instant Messaging ..................................................... 20
Scale and Resilience......................................................................................................21
Conclusion ...................................................................................................................... 22
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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INTRODUCTION The Acano Solution integrates with Microsoft Lync to extend the reach of Lync to the nonLync world, while preserving the Lync experience for Lync participants.
Acano’s approach to integration is based on our belief that technology should be
invisible to end-users. People should not need to know what systems meeting
participants are using, or worry whether they will be able to connect to them. Rather, they
should be able to reach anyone they want, whether they are using Lync or not, receiving
the full feature set and user experience they expect.
This document outlines the architecture for Acano-Lync integration, and describes
features of the current Acano integration with Lync as well as forward-looking features for
future releases. It also covers how this Lync integration can be extended to cover
integration with Skype.
Note: This document is forward-looking, and, where noted, some features described are not yet
shipping in software
KEY FEATURES OF THE ACANO LYNC INTEGRATION Acano’s native support for Lync includes:

Integration with both Lync 2010 and Lync 2013 deployments.

Support for multiple deployment models, covering both on-premise and direct
federation to remote Lync setups.

Lync Edge server support in order to call “external” Lync clients.

Integration with Skype.

The ability to facilitate point-to-point calls between Lync deployments and non-Lync
systems.

The ability for any combination of Lync and non-Lync systems to participate in
multipoint conference calls (more than two participants).
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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
Active Directory integration and dial plan allowing users to find each other and
meetings rooms via directory search, whether those systems are Lync or non-Lync.

Supporting multiple native user experiences for placing calls: selecting a user from
directory or favourites, selecting and calling multiple users at once to start a
multipoint call, “drag and drop” call escalation.

Bidirectional content sharing, including support for BFCP/H.264 (SIP) and RDP (Lync)
with transcoding.

Non-Lync systems support including SIP voice, desktop video, room, multi-screen
telepresence systems, WebRTC, and Acano’s native clients. Vendors supported
include Cisco, Polycom and Avaya.

Full support of major audio and video coding standards, with automatic on-demand
transcoding, including between H.264UC (Lync 2013), RTVideo (Lync 2010), H.264
High and Baseline profiles (SIP video systems), VP8 (WebRTC), with demonstrated
support for H.265 and VP9.

Features for in-call media quality including support for Lync 2010 and 2013 FEC
(forward error correction), multi-layered SVC encoding (UCConfig mode 1), automatic
bandwidth estimation and down-speeding.

Instant Messaging / chat support between Lync and non-Lync systems.

Presence support for both meeting rooms and clients.

Security: Encryption support on all call legs, FIPS and JITC certification.

High capacity and scalable software solution: a fully distributed, fault tolerant, and
scalable architecture including geographic distribution with hundreds of fullytranscoded concurrent video calls or thousands of audio calls supported per server.
HOW IT WORKS BASIC ARCHITECTURE
At its core, the Acano solution can act as a fully-transcoding gateway and conferencing
bridge that can establish SIP trunks to Lync and non-Lync systems. We use Cisco VCS
and an on-premise Lync deployment in this example.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Lync Edge
Lync
Federation
Microsoft
Lync Edge
Lync
Lync client
Lync client
Acano
Acano Core
Edge
Video BC
Video GK
(VCS-E)
(VCS-C)
VC endpoint
VC endpoint
LAN
External Devices
DMZ
Internal Devices
STARTING SIMPLE: TRANSPARENT GATEWAY FOR POINT-TO-POINT
CALLS TO SIP
The Acano solution facilitates calls between Lync deployments and non-Lync systems via
simple static routes and dial plan configuration. Lync calls are routed into the Call Bridge
component located on the Acano Core unit, and corresponding outbound calls are then
placed to the SIP call control device. Calls from a SIP deployment are routed back to the
Lync environment.
The Acano Call Bridge software component ties the call legs together, and handles all
necessary protocol and media conversions. Calls simply work, with any user being able to
call any other user without having to know the type of system that they are using.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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1. Calls
Microsoft
[email protected]
Lync
Lync client
[email protected]
2. Search rule redirect call
to the Call Bridge
Acano Core
3. Call Bridge redirects call
to SIP call control
4. Call routed to
registered endpoint
5. Call received
Video GK
(VCS-C)
VC endpoint
[email protected]
POINT-TO-POINT CALLS TO AN ACANO CLIENT OR WEBRTC
Acano supplies fully-featured software clients for platforms including Windows, Mac OSX,
and iOS, as well as a WebRTC solution for users that connect via a browser. Point-to-point
calls can be set up to and from these clients, with the dial plan on Lync, Acano and SIP
solutions working to provide any-to-any connectivity.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Lync client
[email protected]
Microsoft
Lync
*@example.co
*@vc.example.com
m
*@acano.example.co
m
Acano Edge
Acano Core
Acano clients
*@vc.example.co
*@example.com
[email protected]
m
*@acano.example.co
Video GK
m
(VCS-C)
VC endpoint
[email protected]
DEALING WITH MEDIA
Many Lync gateway solutions either transcode media or pass it through, but the Acano
solution does both. It integrates best-in-class, high-density media transcoding
functionality with the ability to pass through a video stream. It makes dynamic decisions
about whether the media needs to be transcoded or simply passed through, and it can
switch between the two modes on a frame-by-frame basis.
The Acano Solution currently supports all major current video and audio standards, and
has demonstrated capability for software upgrades to future standards such as H.265
and VP9. This allows it to establish the very highest quality of call by allowing each call
leg to connect using its preferred native standard, with any necessary conversion being
handled automatically by the Acano Solution.

The SIP call leg offers a broad range of media codec support, including high profile
H.264 support with resolution up to 1080p, BFCP content support up to 1920x1200,
and ultra wideband AAC-LD audio.

The Lync call leg offers HD RTVideo and 1080p H264UC/SVC support, application
and screen sharing with RDP.
Other approaches to achieving a Lync-to-SIP gateway function with no media transcoding
use a back-to-back user agent and header re-writing to mangle SIP H.264 to Lync
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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H.264UC. However, that strategy does not support content sharing with Lync 2010, or
with Lync clients that only support RTVideo (e.g. Lync client on Mac OS X). Also, this is an
inherently fragile solution that produces streams that are not interoperable with many SIP
endpoints.
HOW A CALL IS MADE – DIRECTORY INTEGRATION
The basic gateway setup allows Lync users to call non-Lync users (and vice versa) via
URI. It is possible to just enter the URI into the client; however, this is not particularly userfriendly.
On the Lync side, the URIs required to call SIP or Acano participants can be added to the
contacts or favourites in the Lync client. At that point, a user can simply click to call. Even
better, the fact that both Lync and Acano both use Active Directory (AD) means that it is
possible to create contacts in the AD such that non-Lync users appear in the directory
search on Lync, and vice versa.
DEALING WITH REAL NETWORK CONDITIONS
Lync and SIP have different ways of adapting media flows to network conditions. For
example, even something as basic as establishing the call rate is different in the Lync and
SIP worlds.
For SIP, this is usually a manual process with the speed determined by a setting at dialtime, or with statically configured maximum rates based on the dial plan. When the rate is
set incorrectly, or there is packet loss or contention, a SIP device will usually attempt to
improve the situation by lowering the call rate dynamically.
In the Lync world, call rate is automatically determined per call. Lync uses special
bandwidth estimation algorithms to establish a good call rate. In addition, Lync
automatically uses media resiliency techniques. Forward error correction (FEC) is used in
the media stream to protect against packet loss. When H.264 UC (SVC) is used, layered
encoding provides a packet loss-resilient encoding structure. WebRTC and Acano clients
use other techniques for media resiliency.
Acano’s approach is to support all the native tools for each connecting participant to give
the best possible experience. For each client, the Acano solution performs the necessary
negotiation and uses the available tools to optimize the media streams sent to each
participant.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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ACCESS FOR ANY LYNC USER – LYNC EDGE SUPPORT
Until this point it has been assumed that the Lync participant is within the local network,
but external Lync participants can also join a call. When the Lync client is not directly
reachable from the Acano Call Bridge, the Acano solution makes use of the Lync Edge
server. It does so using standard STUN/TURN/ICE mechanisms to optionally route media
through the Lync Edge. The result is that any Lync user who could make a normal Lync
call can also make a call to the Acano Solution. Similarly, any client reachable from Lync
can also be reached from the Acano Solution.
Microsoft
Lync Edge
Lync
Lync client
Media
[email protected]
Acano Core
Video GK
(VCS-C)
VC endpoint
External Devices
DMZ
LAN
[email protected]
Internal Devices
DIRECT FEDERATION WITH LYNC
The deployment described above involves integrating with an on-premise Lync setup. In
the future it will also be possible to integrate directly with remote Lync environments. This
is achieved using Lync’s federation capabilities. In this deployment the Acano server is
deployed with an interface in the DMZ with no NAT between it and the remote Lync
environments, typically meaning on the public internet. This can either be done via
opening ports in both firewalls as shown below, or via placing the Acano in the DMZ.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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It is necessary to configure Lync federation DNS records. This allows the remote Lync
environment to find and route calls to Acano, and vice versa.
Lync
Lync client
Lync client
Lync
Federation
Acano Core
Video BC
Video GK
(VCS-E)
(VCS-C)
VC endpoint
External Devices
VC endpoint
DMZ
LAN
Internal Devices
INTEGRATION WITH SKYPE
The Acano Solution integrates with Skype. It provides the ability to make and receive
gateway calls between Skype and any Acano or SIP client, and also allows Skype users
to call into coSpaces. Any device or coSpace can be added as a contact within Skype, or
a Skype user can be added as a contact in other systems.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Image: An incoming call to Skype from Acano (left), Acano users, SIP endpoints and
coSpaces as contacts in Skype (right)
The architecture of this integration is similar to Lync federation, with connections to
Skype being made to and from the Lync Edge. The connection to Skype utilises the
Microsoft Skype to Lync connectivity. This implementation currently supports presence,
IM and audio calls. Microsoft has indicated video will be supported in the future and
Acano will add video support when it is available.
When configured, the federation of the systems allows calls to be placed in either
direction and this behaves in a similar manner to Lync federation.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Skype
Lync - Skype
Connectivity
Microsoft
Lync Edge
Lync
Skype client
Lync client
Acano Core
Video BC
Video GK
(VCS-E)
(VCS-C)
VC endpoint
External Devices
VC endpoint
DMZ
LAN
Internal Devices
To configure Skype integration, you must provision details of the edge server and your
domains on Microsoft’s systems. For more details see http://products.office.com/en-­‐
us/Lync/lync-­‐skype-­‐connectivity.
CALL ESCALATION
Escalation is a general term for adding new communication path(s) between users to an
existing single path. Common examples are:

Users are in an IM chat and decide to escalate that to an audio or video call. It is very
common for a call to start as just an IM chat e.g. to establish if now is a good time to
make the potentially more involved audio or video call.

Two users are in an audio call and decide to add video.

Two users are in a video call and decide to add in a third participant, transitioning the
call from point-to-point to a multi-party conference.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Although escalation is a concept relevant to both the Lync and non-Lync worlds, it is a
particularly common way of doing things for Lync The Lync client user interface is geared
around starting conversations with chat, and around establishing ad hoc multi-party calls
via an intuitive “drag and drop” mechanism which means simply calling one person then
adding in additional people by dragging their names out of the contact list or the
directory into the call window.
Acano supports all of these escalation paths correctly, regardless of whether the person
called is native Lync or non-Lync, which is a very important aspect of preserving the
native user experience for Lync users. With most alternative Lync interoperability
solutions, if a Lync user were to attempt to escalate a call to a non-Lync user in the way
they do with fellow Lync users, the call would fail. Users would be confused and most
likely call technical support!
GETTING INTERESTING – MULTIPOINT CALLS
Typically, multipoint calls in the Lync and SIP worlds offer quite different user
experiences. Lync itself gives very different experiences between Lync 2010 and Lync
2013.
Using Lync 2010, the experience is limited. Lync 2010 participants can use video at up to
HD 720p resolution in a point-to-point call; however in a multipoint call, the Lync
conferencing component (AVMCU) restricts the video to only VGA (640x480) and a
“voice-switched” layout in which only the current active speaker is visible.
Lync 2013 uses H264 scalable video (SVC) and multi-stream technologies to provide a
very different experience. With Lync 2013 up to five participants’ video is visible at any
one time in a “gallery layout” in which all participants have equal prominence.
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Image: Lync multipoint call showing “gallery view”, participant list, and conference
controls
In SIP calls, the user would expect so see a high quality/resolution “continuous presence”
layout, in which multiple meeting participants are visible on screen simultaneously. With a
modern multipoint bridge (MCU) it is normal to offer a choice of layouts at high definition
resolution.
The Acano solution has unrivalled integrated multipoint capabilities. In the pure non-Lync
case, the Acano solution uses a combination of switching and transcoding techniques to
give full continuous presence at up to 1080p resolution at 60 frames per second. Support
for all major video and audio standards allows any SIP device, WebRTC, desktop and
mobile clients to participate in a multipoint call, each receiving optimal video and audio
streams individually tailored to the device’s capabilities: resolution, bandwidth, and size
of screen, as well as the current network conditions.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Image: typical SIP multipoint call
In addition to high quality video, other important features of a multipoint call that are
important to preserve are:

Participant list: this shows the name of all parties in the call regardless of how they
joined

Correct presentation sharing behaviour

In-call controls such as muting, spotlight feature, etc.

Escalation
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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MIXED MULTIPOINT CALLS – WHO HOSTS THE CONFERENCING?
In the case of a multipoint call containing both Lync and non-Lync participants, things get
tricky. Both the Lync and non-Lync worlds are each capable of doing the conferencing
part. There are at least three different potential solutions!
SIP IS THE BEST! DO THE CONFERENCING IN THE SIP ENVIRONMENT
If you take a “SIP world” view, then one answer is to gateway all the Lync calls into SIP
calls and connect everything to a SIP conferencing bridge. This is the solution you’d get,
for example, with a Cisco B2BUA and bridge. Whilst this works and provides a good user
experience for the SIP users, it is a bad user experience on the Lync side.

Good: SIP participant sees all participants and the correct participant list

Bad: Lync participant sees one participant. Even if the video supplied is continuous
presence, this is NOT the gallery view they expect. The participant list shows just one
person in the call. Escalation does not work from Lync.
Acano
Server
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Image: Incorrect Lync user experience when a multipoint call is “hosted on the SIP
side” It is not the correct Lync-style gallery view, the Lync client thinks that there is
only one participant in the call, and in-call controls such as the spotlight feature are
lost.
LYNC IS THE BEST! DO THE CONFERENCING IN THE LYNC ENVIRONMENT
This is the opposite, Lync-centric approach, where the multipoint call is established as a
Lync conference. In this case, the SIP participants appear to Lync as additional Lync
participants connected via the gateway functionality. For this to work, the gateway needs
to provide additional Lync conferencing functionality and provide the necessary media
streams to Lync. This functionality is not the same as that required to make point-to-point
calls.

Good: Lync participants see the correct gallery view and the correct participant list
Escalation works correctly.

Bad: Non-Lync experience is poor; only a voice-switched layout is seen.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Microsoft
Lync Focus
Acano
THE ACANO SOLUTION – BEST OF BOTH WORLDS
The Acano Solution can do both the Sip-centric and Lync-centric solutions. The solution
you get is automatically chosen depending on who establishes the call. If the multipoint
call is set up on the non-Lync side, e.g. by calling out to Lync then you get the SIP-style
conference. If the call is established initially as a Lync multipoint call (e.g. by drag and
drop escalation) then you end up with a Lync-style conference with the Acano solution
providing all of the Lync conferencing functionality on behalf of the SIP participants.
However, we are also working on something really cool – the ability to do the
conferencing for the Lync participants on the Lync side and for the non-Lync participants
on Acano *at the same time*.
This approach uses the Acano Solution’s ability to be both a switching SVC bridge and a
transcoding bridge; the Acano Solution receives (and transmits) multiple individual SVC
streams to the Lync conference and transcodes these into the SIP side of the conference.
Both sides would get the correct user experience irrespective of how the call is
established, and all in-call features would work as expected from both sides.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Microsoft
Lync Focus
Acano
IS ANYBODY THERE? PRESENCE SUPPORT
With the Acano Lync integration, it is possible to see presence information for Acano
users from within either Lync. Presence shows whether a user is online, and if he/she is
currently in a call. The status of an Acano coSpace is also provided to Lync users via the
same mechanism. This enables a Lync user to see whether there are any participants
already within a coSpace without joining it.
The Skype integration provides equivalent functionality for Skype users for both Acano
users and coSpaces.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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Image: Presence shown on Lync client for Lync participants (e.g. Alex Lloyd-Adams) as
well as non-Lync users via Acano (e.g. Jonathan James, Andy Pepperell) and for a
coSpace (Acano coSpace).
UNIFIED COMMUNICATIONS – INSTANT MESSAGING
Unified communications is not just about audio and video. The Acano solution allows
instant messages to be exchanged directly between the Lync and non-Lync worlds. A
message can be posted from a Lync client to a coSpace. Any message posted to the
coSpace is sent to all connected Lync clients and is also persistently stored as part of the
coSpace.
The same functionality exists for Skype users, with the ability to send messages to a
coSpace from Skype, and to receive messages from the coSpace within the client.
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Image: Showing chat between a Lync user and a coSpace
SCALE AND RESILIENCE
The Acano solution comprises standard x86 software that can be deployed on a choice
of platforms, for example, an Acano-supplied server, or as a virtualized deployment on
standard hypervisors.
Even a single Acano instance is highly scalable and resilient, supporting hundreds of
simultaneous fully-transcoded Lync to non-Lync calls or meetings.
Additionally, the Acano Solution is fully distributed, allowing additional scale and
resilience by deploying multiple Acano instances, including for geographic distribution.
Capacity grows in proportion to the number of deployed instances; resilience comes
through installing excess capacity – if an instance fails the load can be taken up by the
remaining Acano servers. Finally, for geographically distributed systems individual Acano
servers/server clusters can be co-located with each Lync Front-end pool. Using resilient
trunking between the co-located Acano and Lync clusters provides a resilient, distributed,
solution at scale.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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CONCLUSION Acano’s native Lync integration preserves the Lync experience for Lync users, while
extending their reach to the non-Lync world. Participants communicate across and
between organizations without worrying about the underlying technology.
Every company can customize and optimize their UC environment with flexible
deployment options (appliance, virtual server, or cloud) and a rich and tightly-packaged
set of multi-media collaboration features. Users benefit from a common dial plan,
federated IM and presence, native conferencing integration, expanded client and
endpoint support, increased capacity – and more – to collaborate with anyone they
choose.
© 2014 Acano (UK) Ltd. All rights reserved.
This document is provided for information purposes only and its contents are subject to
change without notice. This document may not be reproduced or transmitted in any form
or by any means, for any purpose other than the recipient’s personal use, without our
prior written permission.
Acano and coSpace are trademarks of Acano. Other names may be trademarks of their
respective owners.
Acano White Paper: Microsoft Lync Integration Architecture – June 2014
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