Lync Server 2013: Network Quality considerations in LAN, WAN and Wi-Fi
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Lync Server 2013: Network Quality considerations in LAN, WAN and Wi-Fi

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•VoIP Metrics ...

•VoIP Metrics
•Demo of how the Lync client notifies users of poor network
•Codecs and Bandwith
•Lync Bandwith planning
•Short demo of the Lync bandwith calculator
•QoS in networks
•Optimizing for voice in Wi-Fi with different vendors

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  • Common causes: Processing: Encoding / decoding Serialization: Clocking packet onto the wire Network: Queuing and buffer overflow Propagation: Distance related delay Queuing at routers is the most unpredictable component of overall delay
  • Two common types: Random: Occurs over time Single packet here and there “ Bursty”: Contiguous packets dropped Caused by: Router algorithms used to prevent congestion are the primary cause, i.e., RED and WRED Buffer overflow Transmission errors Packet corruption
  • Measure of time variability in arrival of successive packets, generally in milliseconds. Caused by packets taking different routes due to: Load balancers Re-direction due to router congestion
  • Media Endpoints detect & manage distribution of available BW Prioritize Audio first distribute remaining bandwidth to Application Sharing, Video, and File Transfer Choose best quality Audio codec, video resolution/frame rate for available BW Adapt to network & change codecs to optimize experience during a session Bandwidth requirements determined by Codec choice: Microsoft RT-Audio & RT-Video, G.711, G.722, etc. Network performance: Using FEC for redundant audio encoding Channel Activity: Voice activity and video content TechReady12 02/05/13 © 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
  • The overall recommendation, let Lync scale for performance
  • Control maximum bandwidth by using VideoBitRateKB and TotalReceiveBitRateKB Value applies to P2P and conference calls Same bandwidth limits apply separately to panoramic video Recommended settings: Send and receive limits should be set to same value Default: Best quality. For networks which can handle average video bitrates of 600kbps for P2P and 200kbps for conference calls 1000 kbps: Usually 848x480 in P2P and 240x240 resolution in multi-view 350 kbps: Requires multi-view to be disabled. Allows 424x240 resolution.
  • MaxVideoConferencingResolution The MaxVideoConferencingResolution parameter controls the maximum video resolution on legacy clients and does not apply to Lync 2013 Preview clients. The setting remains to ensure administrators can continue to control bandwidth usage of user running clients prior to Lync 2013 Preview.
  • Policy Server role in Lync Server implements CAC Admins configure logical sites based on groupings of subnets Enforce policies on links between sites Bandwidth available for audio, video WAN link bandwidth policies Applied dynamically when session crosses network link with policy set Limits the session to a maximum allowed bandwidth level Re-route or fail session when bandwidth not available Seamless support for roaming users on moving between different sites Allows Internet to be used for overflow of traffic Avoid PSTN call charges Support alternate path & failover of video sessions
  • Three CAC profiles Session limit determines what codecs are being used Here is a scenario where audio session limit is 60 It is running the best codec it can, wb no fec
  • When something happends to the network, bad wireless connection Media stack will adjust the codec with FEC Needs to go to NB and FEC
  • Media stack will adjust the codec with FEC Needs to go to NB and FEC It will work and good quality of experience is maintained for the user
  • Flere bærabare pcer er på nett
  • Shared Medium Interference in 2.4 gigahertz (GHz) (‘noisy‘) Bluetooth, Appliances and cordless phones Other access points (APs) on the same channel nearby Limited band selection in 2.4 GHz band Only three non-overlapping channels By design Wi-Fi standard was designed for none-real time data usage Continuous real-time data flow requirement was not accounted for
  • Telefoner kan ha dårligere dekning enn laptopper Små antenner og enkle kanaler

Lync Server 2013: Network Quality considerations in LAN, WAN and Wi-Fi Lync Server 2013: Network Quality considerations in LAN, WAN and Wi-Fi Presentation Transcript

  • Ståle HansenLync Server 2013Network Quality considerations in LAN,WAN and Wi-Fi
  • ObjectiveBetter understanding of Lync 2013 and network impact• What is “Good” Voice Quality?• VoIP Metrics• Codecs and Bandwith• LAN, WAN and Wi-Fi
  • Ståle HansenTechnical Evangelist @ AteaV-TSP @ MicrosoftBlog @ msunified.netCompany blog @ LyncAtea.noCo-Author Lync Master Class @ LyncLab.noContributor @ TheUCArchitects PodCast
  • #NICLync#NIC2013@StaleHansen
  • What is “Good” Voice Quality?• Users not noticing Voice Quality issues • is what defines success here
  • VoIP MetricsWhat are we looking for?
  • Delay / Latency• Recommendation • Keep combined total two way delay below 150 ms
  • Packet Loss• Requirement for traditional VoIP • Limit to < 1% loss (end to end)• Requirement for RTAudio • Limit to < 10% loss (end to end)
  • Jitter• Requirement for VoIP • Limit jitter to < 30ms
  • Impact on a Lync conversationDemo
  • SIP SRTP / RTCP 11 22 33 44 55 Perfect Network11 22 33 44 55
  • SIP SRTP / RTCP 11 22 44 55 55 44 11 22 44 55 44 33 33 22 2211 22 33 44 55 11 Poor FForward Error orward Error CCorrection orrection Network22 33 33 44 44 55 55 66
  • Codecs and Bandwith
  • Bandwidth• Media Endpoints detect & manage distribution of available BW • Prioritize Audio first• Bandwidth requirements determined by • Codec choice • Network performance • Channel Activity
  • Bandwith (BW)Codecs and Bandwith requirements
  • For planning in a wellmanaged, right-sized network,use Max BW w/o FEC.If the network will beconstrained and you want topreserve quality, use Max BWwith FEC.When understanding howmuch bandwidth at any giventime is being used, use theTypical BW numbers. Not forplanning, as usage will begreater at times.
  • Bandwith – Video
  • Typical Video Bandwidth Usage• Preliminary data from Lync 2013 Preview deployments at Microsoft and TAP customers• Video usage doubled compared to Lync 2010• P2P video calls: • Average send/receive video bandwidth ~600kbps • ~75% of users with default video resolution of 424x240 • ~25% increase video window to obtain 640x360 or HD video• Conference video calls: • Data sharing reduces screen real estate for video in most calls -> small video resolution of 320x180 • Receive: average of 2.5 video streams using ~500kbps • Send: average of 1.6 video streams using ~350kbps 18
  • Bandwith – Application Sharing• Application sharing bandwidth consumption dependent on session content and screen resolution• TCP based sessions with built-in congestion control• Traffic is bursty in nature• End user policy limits to cap spikes
  • Bandwith (BW)Planning recommendations
  • Video Bandwidth Recommendations• Control maximum bandwidth by using • VideoBitRateKB • TotalReceiveBitRateKB• Recommended settings: • Send and receive limits should be set to same value • Default: Best quality. For networks which can handle average video bitrates of 600kbps for P2P and 200kbps for conference calls • 1000 kbps: Usually 848x480 in P2P and 240x240 resolution in multi-view • 350 kbps: Requires multi-view to be disabled. Allows 424x240 resolution. 21
  • Video Bandwidth Recommendations 22
  • Set-CsConferencingPolicyDemo
  • NetworkLAN, WAN and Wi-Fi
  • Call Admission Control (CAC)• Policy Server role in Lync Server implements CAC • Admins configure logical sites based on groupings of subnets• WAN link bandwidth policies • Applied dynamically when session crosses network link with policy set• Seamless support for roaming users on moving between different sites• PSTN reroute• Allows Internet to be used for overflow of traffic • Support alternate path & failover of video sessions
  • RT Audio WB (no FEC)Seattle WAN Link Policy: New York Audio Session Limit = 60 Kbps
  • RT Audio WB (No FEC)Internet Seattle WAN Link Policy: Audio Session Limit = 60 Kbps
  • RT Audio NB (+ FEC)Internet Seattle WAN Link Policy: Audio Session Limit = 60 Kbps
  • Bandwith Calculator OverviewDemo
  • End to end networking• LAN• WAN• Wi-Fi
  • Quality of Service (QoS)
  • Differentiated Services Code Point (DSCP)…AKA DiffServ•Recommended: • When Right Provisioning not possible and on Constrained WAN Links • pair with WAN bandwidth policies • Prioritization already deployed for other VoIP solution
  • Challenge:DSCP tagging is not done by Lync It’s done on OS level
  • Endpoint diversity LAN Wi-Fi Bring Your Own Device
  • Wi-Fi problem areas• Shared medium• Limited band selection in 2.4 GHz band• Was designed for none-real time data usage• Deployed for access, not throughput
  • Microsoft recommendation• Deploy concurrent dual-band AP • Applicable for enterprise, home, and hotspot • Move devices to 5 GHz (if possible) 21 channels • Less interference • Wider channel selection• Consider quality and features of Wireless NICs • Wi-Fi alliance certification • Multiple antennae support (11n)
  • The 802.11 family explained• 802.11a • 802.11g • 5 GHz • 2,4 GHz • 54 Mbps • 54 Mbps• 802.11b • 802.11n • 2,4 GHz • 2,4 GHz (70 Mbps) • 11 Mbps • 5 GHz (150 Mbit) • Multiple channels • Multiple antennas (MIMO)
  • Device Wi-Fi support• Nokia Lumia 820 • Samsung ATIV Smart PC Pro • 802.11a/b/g/n • 802.11n• HTC 8S Atlantic Blue • Samsung Galaxy Tab 2 10.1“ • 802.11b/g/n • 802.11b/g/n• HTC One X Plus Black • HP Envy X2 11-g001 • 802.11a/b/g/n • 802.11n• Samsung GT-I8750 Ativ S • Apple iPad 2 Wi-Fi • 802.11a/b/g/n • 802.11a/b/g/n• Samsung Galaxy S III • Microsoft Surface RT • 802.11a/b/g/n • 802.11a/b/g/n• Apple iPhone 5 • Microsoft Surface RT • 802.11a/b/g/n • 802.11a/b/g/n• Apple iPad mini Wi-Fi • Microsoft Surface PRO • 802.11a/b/g/n • 802.11a/b/g/n
  • Voice optimized Wi-Fi• Aruba • Lync certified solution• Meru • Lync certified solution (March)• Cisco • Lots of experience of voice over Wi-Fi
  • How to optimize for voice over Wi-Fi• All vendors tag Wi-Fi Lync traffic with DSCP value • Great for unmanaged devices• High-density AP deployments • Closer to users • Just add more accesspoints• Fast inter-AP handover support• All venderos stress end to end optimization • Endpoint -> Wi-Fi -> LAN -> WAN -> LAN -> Wi-Fi -> Endpoint
  • Data Center L2/L3
  • Aruba• Fingerprinting to detect multimedia endpoints • Tag Lync traffic• Multichannel AP deployment• Fast AP handover• Will redirect clients to AP’s with less load
  • Meru• Uses single SSID accross the entire deployment • Zero-Latency Roaming• Uses three channels with three different speeds• Easy deployment, just add AP’s
  • Cisco• Just released AVC that tag Lync traffic at AP • Deep packet inspection • AVC profiler • En for voice og video • MS Lync• Band select, forcing acces points to 5 GHz• If one acces point goes down• Coverage hole detection, increase send strength• Uses its CleanAir technology to detect interference • Spectrum analyzer • All new access points have this today • Change channel when noise
  • Key Takeaways• “Good” Voice Quality - is what is expected• VoIP Metrics – Tells us about the health of the network• Codecs and Bandwith – Helps us design for QoE• LAN, WAN and Wi-Fi – Wi-Fi is the new norm
  • Questions?