Scenarios
Lync-Skype Audio (v1)
Lync-Skype Video (v2)
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Add to contact list/Block users [Lync to MSA]
Block Skype Connectivity
Instant Messages and Presence Updates
P2P Audio Call
Escalate IM session to Audio Call
Hold/Resume, Mute/UnMute, Transfer
Everything in v1
Make Audio + Video Calls
Reject Video for inbound calls
Escalate Audio only calls by adding video
Pause/Resume Video
Architecture improvements
• New Skype cloud for improved call set up and control.
• New gateway connects Skype cloud to Lync Online for
signalling and call control.
• Uses Lync’s federation access architecture that routes to
both v1 and v2 clouds.
• V1 connectivity will continue to exist as traffic gradually
increases on V2 connectivity.
Connectivity v1 architecture
Legend
signal path
media path
Federation Cloud
Lync Online – Office 365
Connectivity v2 architecture
Legend
signal path
media path
Federation Cloud
Lync Online – Office 365
Call connectivity
• All AV calls flow through the same federation environment set up in v1
• Lync SIP/SDP signalling is terminated at the Skype Cloud edge and translated
into Skype proprietary protocols and vice versa
• Lync to Skype Calls
• AV calls are forked internally to both v1 and v2 clients
• Mediation server supports only Audio
• New Lync Gateway services all v2 calls.
• Skype to Lync Calls
• v2 clients will route calls through v2 Skype Cloud > Lync federation
environment > Lync client
• v1 clients will route calls through v1 Skype Cloud > Lync federation
environment > Lync client
Connectivity v1 call flow
Legend
signal path
media path
Federation Cloud
Call initiated with connection details
Call accepted and returns connection details
Media connection is established
Lync Online – Office 365
Connectivity v2 call flow
Legend
signal path
media path
Federation Cloud
Call initiated with connection details
Call accepted and returns connection details
Media connection is established
Lync Online – Office 365
Platform
Lync
Skype
Windows
Desktop
Lync 2013 (upcoming CU)
Internal trial version
Windows
Modern
Lync Modern (upcoming release)
Coming Soon
Mobile
(Windows
Phone,
iOS,
Android)
Coming soon
Coming Soon
Web App
Not supported
NA
MAC
Potential future support
Coming Soon
Technology improvements
Direct media connectivity between Lync and Skype clients
• SILK has been ported over to Lync desktop client. Coming to other Lync
clients soon.
• SILK will currently only used in Lync-Skype Interop Calls
• G.722 and G.711 remain on the list of common codecs
• Video using H.264 SVC
• Media connectivity using ICE - ICE v19 support added to Skype client
• Along with STUN\TURN for NAT traversal
Codec
Scenario Audio payload
(kbps)
Audio payload + IP Audio payload + IP,
header (kbps)
UDP, RTP (kbps)
Audio payload + IP, UDP,
RTP + FEC (kbps)
G.722
p2p
64
80
92
156
SILK
p2p
36
52
64
100
Network conditions
SILK 36 kbps
G.722 64 kbps
Ideal
4.42
4.31
5% random loss
4.35
4.12
4.0
3.68
5% burst loss
MOS calculated
using ITU-T
P.863 POLQA
Payload Type
Codec
Sampling Rate
Target Bitrate
104
SILK Wideband
16k
36kbps
103
SILK Narrowband
8k
13kbps
Enterprise NAT Traversal Mechanism
Stun/Turn/ICE
SIP uses the source and target IP addresses to establish a session. Network
Address Translation (NAT) modifies IP addresses as packets transit onto the
public internet and thereby renders the INVITE invalid. STUN, TURN and ICE
resolve such session/NAT issues.
Router
❶❷
❸
❶ Host Candidate – Likely to fail
❷ STUN Candidate
❸ TURN Candidate – Edge Relay
Snooper Trace – Lync SIP Invite to Skype
Enabling Lync Skype Federation
If your enterprise is already configured to connect with Windows Messenger via PIC, you are
already set up to federate with Skype!
• Achieved by provisioning via the PIC (Public Instant Messaging Connectivity) system
• Valid for both Lync Online and On-prem.
• Full details at: http://technet.microsoft.com/en-us/library/dn440173.aspx
• Same steps for both audio only federation (current GA) and future video enabled calls
Lync-Skype Connectivity V1
Chat & Audio
Lync-Skype Connectivity opens a new communications door for enterprises searching for inventive and
differentiated opportunities for new customer acquisition, customer retention, and business-toconsumer communications.
Contacts
MSAs)
Router
Sessions
chat & audio
Not included:
Lync-Skype Connectivity V2
With version 2, we now use standard NAT traversal protocols, Signalling is encrypted with TLS and
media uses sRTP directly between callers. We’ve standardized Codecs between the clients and have
added Video !!
Contacts
MSAs
Router
Sessions
Video (H.264)
• Encryption with TLS and sRTP
• NAT Traversal with Stun/Turn/Ice
Not included:
Chat, audio,
Video
Chat, Audio,
Video
Lync Online – Lync Skype Connectivity V2
With version 2, we now use standard NAT traversal protocols, Signalling is encrypted with TLS and
media uses sRTP directly between callers. We’ve standardized Codecs between the clients and have
added Video !!
Contacts
MSAs
Router
Sessions
Video (H.264)
• Encryption with TLS and sRTP
• NAT Traversal with Stun/Turn/Ice
Not included:
Chat, audio,
Video
Chat, Audio,
Video