microsoft ® lync™ server 2010 voice quality considerations module 13 microsoft corporation

Microsoft® Lync™ Server 2010Voice Quality ConsiderationsModule 13

Microsoft Corporation

Session Objectives

• Understand the important factors that determine end user voice quality experiences

• Use the Lync Server 2010 support for network layer voice traffic management

• Recognize the Lync Server 2010 improvements for voice quality performance and end user experiences

• Know how to monitor and diagnose voice quality issues

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Voice Quality

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What Defines Voice Quality?• Call Reliability

• Calls get established as expected

• Calls do not drop midway through

• Audio Quality• Users are able to hear everything they need to in their calls

• Who Matters• User quality of experience

• Can I make voice calls successfully?

• Admin quality of life • Can I discover, diagnose, and resolve voice quality issues effectively?

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What Constitutes “Good” Voice Quality?• Good really means good enough

• Starting point for expectations for most Information Workers (IW) is legacy private branch exchange (PBX) for desktop phone• High reliability• Narrow band audio

• “Good enough” can still be highly personal and context sensitive• Up to a point, users will accept lower voice quality given other advantages

• Mobile phones trade mobility for lower call reliability• Internet VoIP users trade price for audio quality

• Bottom Line: Users not noticing voice quality issues is what defines success here

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Network Considerations

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Voice Quality & Bandwidth

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Anatomy of a UC Audio SessionRTP / RTCP

1 2 3 4 5

SIP

8

1 42 53

Anatomy of a UC Audio SessionRTP / RTCP

1 2 3 4 5

1 2 3 42 3

FEC

4 5

12

3

4

2

3

45

1 42 5

1 2 4 5

SIP

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Microsoft Lync Server 2010 Bandwidth Requirements• How much bandwidth is required is determined by:

• Codec

• Network performance• Poor network performance results in redundant encoding of audio content (Forward Error

Correction)

• Content • Voice activity, video motion, app content

• Microsoft Lync Server 2010 Media Endpoints actively manage distribution of bandwidth across UC modalities• Prioritizes Audio first and distributes remaining bandwidth to app sharing, video,

and file transfer as required

• Chooses the best quality audio codec and video resolution for available bandwidth

• May dynamically change codec choices during a session10

UC Session Bandwidth Costs• Bandwidth numbers include

overhead for framing, encryption, and IP routing information in addition to actual encoded media and based on 20ms audio p-times

• Typical bandwidth values bit rate are measurements of typical activity level values under good network conditions (i.e. no FEC for audio sessions)

• Typical bandwidth number can be used for capacity planning to assess if a network should be considered “right provisioned”

• Upper Limit numbers can be used for initial capacity planning

• Monitor actual Bandwidth usage of UC sessions and then refine

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Audio/Video Capacity Planning for Peer-to-Peer Sessions

Audio/Video Capacity Planning for Conferences

Audio Capacity Planning for PSTN

Media Codec Typical stream

bandwidth (Kbps)

Maximum stream

bandwidth without FEC

Maximum stream

bandwidth with FEC

AudioRTAudio Wideband

39.8 62 91

AudioRTAudioNarrowband

29.3 44.8 56.6

Main video CIF RTVideo 220 260 Not applicable

Main video VGA

RTVideo 508 610 Not applicable

Main video HD RTVideo 1210 1510 Not applicable

Panoramic video

RTVideo 269 360 Not applicableAudio G.722 46.1 100.6 164.6

Audio Siren 25.5 52.6 68.6

Main video CIF RTVideo 220 260 Not applicableMain video VGA

RTVideo 508 610 Not applicable

Panoramic video

RTVideo 269 360 Not applicable

Audio G.711 64.8 97 161

AudioRTAudio Narrowband

30.9 44.8 56.6

Network Layer Voice Traffic Management

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Network Quality of Service – DiffServ• Where do we recommend Quality of Service (QoS)?

• When Right Provisioning not possible and so Constrained WAN Links (pair with WAN bandwidth Policies)

• Audio prioritization already deployed for other Voice over Internet Protocol (VoIP) solution (ensure level playing field)

• Differentiated Services Code Point (DSCP) - field in an IP packet to assign levels of service for network traffic

• Example “Fully Managed” Network Deployment

Media Type Per Hop Behavior

Queuing and Dropping

Notes:

Audio EF Priority Queue Low loss, low latency, low jitter, assured bandwidthPair with WAN Bandwidth Policies on constrained links

Video AF41 BW Queue + DSCP WRED

Class 4. Low drop priority.Pair with WAN Bandwidth Policies on constrained links

SIP Signaling CS3 BW Queue Class 3.Bandwidth allocation should be sufficient to avoid drops

App Sharing AF21 BW Queue + DSCP WRED

Class 2. Low drop priority.Pair with End User Policy Caps

File Transfer AF11 BW Queue + DSCP WRED

Class 1. Low drop priority.Pair with End User Policy Caps

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Network Quality of Service – DiffServ• How to deploy

• Configure separate port ranges for Lync audio, video, app sharing, and file transfer traffic• User same port range for audio on AV Conferencing Servers, Mediation Servers,

Conferencing Auto Attendant (CAA), Conferencing Announcement Service (CAS), Response Group Service (RGS), Call Park

• Use separate port range for video on AV Conferencing Server• Use separate port range for app sharing on AS Conferencing Server• Make Client audio/video port ranges subset of Servers

• E.g. Server audio port range = 49,152 – 57,500• Client audio port range = 57,480 – 57,500

• Environmental factors• Windows® 7 and Windows Vista® Lync 2010 users only use Windows Policy based

QoS to mark based on application and port ranges• Windows XP® Lync 2010 user then marks at router based on port ranges only (or

use Generic QoS) • Lync 2010 Phones mark at endpoints 14

Virtual Local Area Network VLAN Support• VLANs can help with address space management when

deploying a large number of Lync 2010 IP phones• VLAN Discovery by Lync Phones

• Link Layer Discovery Protocol (LLDP) support added in Lync Server 2010 for VLAN discovery (plus E.911 location information and power management)

• DHCP option still available where LLDP is not supported

• 802.1P traffic prioritization also supported for Office Communications Server (OCS) 2007 R2 Phones

• Recommendations• Limit use of VLAN for OCS Phones and address space/port

management15

Microsoft Lync Server 2010 Voice Quality Improvements

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Media Bypass• Lync Server 2010 introduces media bypass of the Mediation Server:

• In OCS 2007 and OCS 2007 R2 of UC-PSTN call signaling and media always passes through a Mediation Server

• In Lync Server 2010, whenever possible, media for those calls will flow directly to the gateway (GW) without traversing Mediation Server• Applies where media streams stay within a site

• Improves Audio Quality and facilitates reduction of TCO• Direct routing of media between Lync 2010 endpoints and GWs means

no redundant network hops are used• Saves Bandwidth and reduces end-to-end audio latency

• Less media processing on Mediation Server• Fewer Mediation Servers deployed• Recommend collocation of MS role with Front Ends

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Lync Server 2010 Core Performance Improvements• Calls staying established

• Signaling and media are separate sessions• Signaling TCP• Media UDP or TCP

• Voice Resiliency allows to continue in the event of disruption to the signaling session• Middleboxes resetting TCP connections• Microsoft Lync Server 2010 failover

• Higher quality audio (and video)• Less echo, less noise

• Improved AEC filter bank and Dynamic Non-Linear Processing

• Improved voice quality in conferencing• Default voice codec in conference is G.722• VGA video conferencing

• Optimizations for supporting audio/video on netbooks 18

Devices and Gateways

• Lync Server 2010 introduces the next generation of stand alone Lync 2010 Phone devices• Wider range of stand alone IP phones spanning Common Area, IW Desk Worker, Executive

and Conference Room devices

• New USB phone devices for low cost desktop phone replacement• Initial trial deployment of 600 in MSIT resulted in a net satisfaction (NSAT) score of 153 – highest scoring

device ever deployed

• New hardware ergonomic and acoustics

• Improved speakerphone performance

• Certification• Audio Performance testing added to the certification program for both Devices and GWs

• System Center Operations Manager (SCOM)• Advanced partners will provide a SCOM pack to allow GW monitoring in same Management

Interface as Lync Server Roles19

E2E Experiences: End Users

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Demo: End User Experience

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Admin Extensibility

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Summary – End User Experiences• Provide direct, actionable feedback to end users on voice

quality issues• Help them understand and optimize experience• Reduce calls to helpdesk

• Simplified audio device management• Higher visibility of “test call” option• Automatic detection of multiple laptops in same room

• More than one person in a conference room connected to audio with open speaker/microphone causes echo

• In call audio quality notifications• Extensible by Admin to add link to local support pages

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E2E Experiences: Admins

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Demo: Admin Experience

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Session Failure Rate Metrics• Some failures have multiple root causes; some benign and some real

problems• 10404 – “User not found”

• Did user misdial a phone number or did Admin misconfigure routing rule mangle the number?

• 52021 – “Call terminated on media connectivity?”• Did user drop from wireless network or did server crash?

• 52074 – “Previous sign out was abnormal”• Did user PC crash/run out of power/lose network or did a HLB/router/server fail?

• Use 3:00 am wake-up call test to help classify• Monitor call reliability through unexpected failures• Expected failures can still be important

• Establish baselines of expected failures and identify significant deviations from them

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Summary – Admin Experiences• Richer reports for UC usage and quality monitoring

• Report key cost saving data for ROI Analysis

• Targeted reports for Session Reliability and Audio Quality

• Provide IP phone reports for Asset Management

• A dashboard with key usage and diagnostic information• Proactively inform Admins summary trends for usage and health of the deployment

• Comprehensive data for usage tracking and voice quality diagnostics:• Collected usage data for Lync Server 2010 new features

• Collected data for conference, registration, device and Lync Server 2010 new feature diagnostics

• Optimized call CDR and QoE database schema to support partners developing third party Monitoring solutions

• Improved SCOM alerting:• Added call reliability monitoring and alerting

• Enhanced media quality monitoring and alerting for locations and gateways27

Key Takeaways• Recipe for Success

• Network• Bandwidth policies, including CAC• Support for DiffServ and VLANs

• Devices and Gateways• Exciting new range of Phones• Microsoft certification

• Core performance improvements• Session Resiliency• Media Performance

• Rich End user and admin experiences

• Succeed at Voice Quality and redefine what it means to communicate in your business

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Q&A

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Demo: End User Experience

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Device Selection

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Device Selection

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Test Call

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Test Call

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35

36

Admin Extensibility

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In Call Audio Quality Feedback

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In Call Audio Quality Feedback

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In Call Audio Quality Feedback

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Disaster Recovery

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Disaster Recovery

42

Disaster Recovery

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Demo: Admin Experience

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QMS Reports

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Location Based Audio Quality

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Session Reliability Summary

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Session Reliability Trends

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Top Failures

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User Activity Report

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Session Detail Drill Down

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© 2010 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.

© 2011 Microsoft Corporation.  All rights reserved.  Microsoft, Windows, 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.  This document may contain information related to pre-release software, which may be substantially modified before its first commercial release. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED  OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION. Unless otherwise noted, the example companies, organizations, products, domain names, e-mail addresses, logos, people, places and events depicted herein are fictitious, and no association with any real company, organization, product, domain name, email address, logo, person, place or event is intended or should be inferred.