User GuideMicrosoft Lync Server 2010 Bandwidth Calculator

MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS DOCUMENT. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation. Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, our provision of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property. The descriptions of other companies products in this document, if any, are provided only as a convenience to you. Any such references should not be considered an endorsement or support by Microsoft. Microsoft cannot guarantee their accuracy, and the products may change over time. Also, the descriptions are intended as brief highlights to aid understanding, rather than as thorough coverage. For authoritative descriptions of these products, please consult their respective manufacturers. 2011 Microsoft Corporation. All rights reserved. Any use or distribution of these materials without express authorization of Microsoft Corp. is strictly prohibited. Microsoft, Windows ,Excel, and Lync are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. The names of actual companies and products mentioned herein may be the trademarks of their respective owners. Page ii

Revision SheetChange RecordDate 06 August 2010 02 December 2010 Author Keith Hanna Version 0.1 Change reference Initial document

Craig Hill

0.2

Updated content to reflect changes in BW Calculator approach. Updates based on Peer review

03 December 2010 13 December 2010 11 March 2011 13 March 2011

Craig Hill

0.3

Jim Purcell Craig Hill Jim Purcell

0.4

Editorial review and removed headers and footers Editorial review

0.5

Craig Hill

0.6

Updated based on Editorial review

Page iii

Table of Contents1 Summary..........................................................................1 2 Introduction......................................................................22.1 Audience..................................................................................................2

3 General Information and Assumptions................................2 4 Required information........................................................5 5 Step by step guidance.......................................................55.1 5.2 5.3 5.4 Conventions.............................................................................................5 Flow Chart................................................................................................6 Global Configuration Parameters.............................................................6 Central Sites.............................................................................................75.4.1 5.4.2 5.4.3 5.4.4 Branch Sites................................................................................................7 Personas.....................................................................................................7 Usage Models..............................................................................................7 Summary.....................................................................................................8

5.5

Outputs....................................................................................................9

Outputs

Page iv

1 SummaryBandwidth planning is a key component of deploying the Microsoft Lync Server 2010 communications software. This document and the accompanying tool describe the recommended process for estimating your bandwidth needs for Enterprise Voice, application sharing, and other tasks that Lync Server 2010 supports. Microsoft Consulting Services, along with the Lync Server product team, have coordinated to publish this bandwidth calculator and guidance. This document will be updated periodically with new information and modifications. As a best practice, you should regularly check for the latest update.

Page 1

2 IntroductionCalculating the bandwidth requirements of Lync Server 2010 can be a complex task. This tool provides a framework for architects, consultants, and administrators to estimate the additional network traffic that a Lync Server deployment will generate. The tool can be used both by experienced consultants with expert product knowledge and by customers who dont have specific product knowledge but would like to understand the possible network impacts of a Lync Server deployment. With only the number of users on a particular site, and keeping all other parameters at their default setting, you can estimate the order of magnitude impact of Lync Server on your network. The defaults assume that your users use all communications modalities and have a medium usage profile. For a more detailed view, you will need to refine your user personas to accurately reflect the behavior of your users and the modalities available to them. After you enter customer user personas and usage models into the bandwidth calculator, the output will show a detailed breakdown of the capacity requirement per modality. You can then determine whether you need to provide additional network capacity before you deploy Lync Server 2010. At a glance youll be able to see, for each site, whether the estimated bandwidth required is higher than the bandwidth that you have allocated for real time media. The calculator breaks this information down for central sites and for branch sites. For easy reference, the calculator also produces a table with video bandwidth removed so you can see how video affects your bandwidth requirements at each site.

2.1 AudienceThis document is intended for consultants and system administrators who want to use the accompanying bandwidth calculator to estimate the network impact of Lync Server before they deploy it. It does not require specific knowledge about Lync Server 2010 beyond a general understanding of its key capabilities.

3 General Information and AssumptionsThe Lync Server Bandwidth Calculator uses a number of naming conventions and architecture assumptions to facilitate the modeling of bandwidth for Lync Server 2010 deployments. Only WAN bandwidth is modeled, so LAN bandwidth it not taken into account. Each site has a WAN link, and all intersite traffic uses this link.Page 2

The modeling is based on two site categories that mirror the existing topology definitions for Lync Server, central sites and branch sites.

A central site has the following characteristics: Has at least one Lync Server Front End pool. Provides PSTN dialing access for local users. Hosts Edge Servers. Routes traffic from peer-to-peer calls between central site users and branch site users over the WAN. All central site users PSTN traffic and conferencing traffic remain local to the central site. The relationship between a branch site and a central site can differ greatly depending on services that are deployed at the branch site . The bandwidth calculator allows for the following scenarios: PSTN dialing access through the central site. PSTN dialing access through a PSTN gateway at the branch site. PSTN dialing access through a Survivable Branch Appliance or Survivable Branch Server. The central site is associated with branch sites on the Branch Sites input tab. The bandwidth calculators definition of a branch site is as follows: Is associated with a central site. Has no Lync Server Front End pool and therefore does not home any users. May have Mediation Servers and PSTN gateways. May have a Survivable Branch Appliance or Survivable Branch Server for site resiliency. Obtains conferencing services from the central site, and all associated traffic uses the WAN link. Does not host Edge Servers. Usage modeling in the bandwidth calculator is based on the maximum percentage of users who are concurrently participating in a particular type of session. For example, if PSTN Max Concurrency for Medium is 10%, we expect that for a site with 1000 users during the daily peak there will be 100 users making PSTN calls. The usage models are defined on the Persona Definitions tab and are prepopulated to account for none, low, medium, and high usage. Important: If you have real usage statistics from your own environment, you should override the default entries with your own numbers. The following modalities are currently supported by the calculator: SIP signaling: Instant messaging, presence subscription, and signaling trafficPage 2

Intersite peer-to-peer audio Intersite peer-to-peer video Intersite peer-to-peer application sharing Conference audio Conference video PSTN audio A user persona is assigned to group of users that behave in a similar manner when they are using Lync Server functionality. The persona defines which modalities the assigned users can use and how much they use each one. There are ten fields that you can customize to define personas unique to your organization. The bandwidth calculator supports a maximum of three personas on a single site at any one time. For each persona, you define whether of the corresponding users have none, low, medium, or high usage for each of the modalities defined above. For example, suppose you have a group of administrators that dont use video but have high PSTN usage and medium usage for other functionality. At the site level, you would then assign a number of users to this persona. That persona might look like this: Attribute Name Instant messaging Peer-to-peer audio Peer-to-peer video Application sharing Conference audio Conference video PSTN audio Value Administrator Medium Medium None Medium Medium None High

There are additional configurable elements that can be modified for each site. Well cover call admission control (CAC), default codec for PSTN calls, and the handling of remote users. Call admission control calculations are not directly handled by this calculator; however, we have included the ability to modify default codec selection in specific scenarios in the same way that a call admission control session limit would change codec selection. For each site, you can enable this setting. Here are the impacts on codec selection and calculations: Restrict audio codecs using CAC = NO (Default) Intersite peer-to-peer audio calls use RTA-WB codec for calculations. Conference audio calls use G722 codec for calculations.Page 1

Restrict audio codecs using CAC = YES Intersite peer-to-peer audio calls use RTA-NB codec for calculations. Conference audio calls use Siren codec for calculations.

Although call admission control will also affect PSTN calls, we have not based PSTN call codec selection on the Restrict audio codecs using CAC parameter. We have included a separate parameter to deal with codec selection for PSTN Calls. This parameter affects WAN calculations only if Local PSTN Breakout is set to NO, which indicates that PSTN dialing access is provided from the central site. Use G711 for PSTN audio = YES (Default) PSTN calls, even across the WAN, use G711 codec for calculations.

Use G711 for PSTN audio = NO PSTN calls use RTA-NB codec for calculations.

1 Required informationThe Lync Bandwidth Planning Tool uses a number of profiles to estimate bandwidth requirements. You can use the default profiles if no customer-specific information is available, but detailed information about your specific situation will yield a more accurate result. You can refine the following information elements: Existing bandwidth allocations at each site Total WAN bandwidth on a site link. For example, 10 Mbps MPLS link. Total bandwidth allocated to real-time communications traffic. For example, the site may have a capacity of 10 Mbps, but we want only 3 Mbps to be allocated for real-time communications. Central site Site Name Number of users Up to three custom user personas Branch Sites Site Name Name of central site this branch site is associated with Number of users Up to three custom user personas Local PSTN access (YES/NO): Define whether PSTN dialing access is provided by local gateways or across the WAN from the central site CAC to restrict codec choice (YES/NO): Define whether call admission control is used to restrict audio codecs for peer-to-peer calls and conference audio. If NO (the default), peer-to-peer audioPage 1

uses the RTAudio wideband codec, and conference audio uses G722. If YES, peer-to-peer audio uses the RTAudio narrowband codec, and conference audio uses Siren. Usage Models Prepopulated to account for none, low, medium and high usage. If you have real usage statistics from your own environment, you should override the default entries with your own numbers. Personas Personas can be customized to suit your needs. There are 10 fields that you can customize to define personas unique to your organization. A maximum of three personas can be used on a single site at any one time.

1 Step by step guidance1.1 ConventionsAs you complete the input sections of the calculator, there are a few color-coding conventions that you should take note of: Green = General Data Input Areas Yellow = Advanced Data Input Areas Red/Gray = Read Only / Display Only Areas

1.1 Flow ChartThe flow chart below is included in the spreadsheet calculator included with the tool. It includes hyperlinked buttons to allow fast and easy navigation through the calculator. Note The bandwidth calculator includes macros. To use the calculator, you must enable macros in the Microsoft Excel spreadsheet software.

Page 2

1.2 Global Configuration ParametersGlobal parameters are presented on the Central Sites worksheet that determine whether the output is displayed in Kbps, Mbps, Or Gbps; which values will be used to determine codec bandwidth (Typical, Maximum, or Maximum with FEC); which resolution peer-to-peer (P2P) desktop sharing will be calculated; and the percentage of WAN link bandwidth usage that will trigger an excess usage warning. (The site appears in the worksheet in red).

1.3 Central SitesThe following figure is taken from the Central Sites worksheet. All user input fields are highlighted in green.

Page 2

1.4 Branch SitesAfter your central site is defined, you can start to allocate users to your branch sites. Pay close attention to some of the configurable parameters: Pool Server located in Site: For branch sites, this parameter will always be set to No. Local PSTN Breakout: If Yes, no PSTN traffic traverses the WAN. If No, all PSTN Traffic traverses the WAN. Minimum Threshold for Small Sites: This field allows the tool to enforce a minimum number of sessions for each modality. This parameter is useful for small sites where concurrency percentages dont accurately model actual usage. For example, a site with ten users might require four audio calls and one video call; however, the concurrency number would model only one audio call and 0.1 video calls. The default value is No Minimum. Restrict Audio Codecs using CAC: If set to Yes, this parameter uses RTA-NB instead of RTA-WB for peer audio calls, and it uses Siren instead of G722 for audio conferences. The default value is No.

1.1 Personas

Page 2

1.2 Usage ModelsUsage Scenarios Explained

Presence/IM: Traffic created when a user registers with Lync and subscribes to presence updates. This traffic also includes traffic for sending and receiving instant messages. Intersite Peer Calls: Intersite peer-to-peer calls that include audio and/or video. This category does not include peer-to-peer calls between users at the same site. You can specify whether a user persona will use CIF, VGA or HD for video calls. You can also restrict audio codecs (per site) so that RTA-NB would be used for peer-topeer calls. Audio Conference Session: A user connected to a conference with audio. An audio conference session uses either G722 (the default) or Siren as the codec. If codec candidates are restricted with CAC, Siren will be used for planning. Video Conference Session: A user connected to a conference with video. Intersite Peer-to-Peer Desktop Sharing: A user doing application sharing or desktop sharing with another user at another site. PSTN Audio Session: A user making a PSTN call. This calculator will use G711 codec for calculations unless Use G711 for PSTN audio is set to NO, in which case the calculator will use RTA-NB.

1.1 SummaryBy choosing the options described above for each branch site, you can accommodate the branch site architectures shown in the following figure.

Page 1

PSTN

Branch Site (Local PSTN and SBA /SBS

PSTN

Central SiteBranch Site (Users Only)

Branch Site (Local PSTN)

PSTN

Figure 10 Architectures Supported

1.2 OutputsThe Graphical Results worksheet is your starting point for results. It displays a summary of WAN bandwidth required per site and provides a graphical comparison between the bandwidth estimated and the bandwidth available on the WAN link.

Page 2

Further information can be found on the Deployment Readiness worksheet, which contains a summary of the number of sites that will require a WAN upgrade before they are capable of carrying the estimated traffic volume.

If youre looking for a detailed breakout for each modality, go to the Branch Sites or Central Sites worksheet and scroll to the right to see a breakdown of WAN bandwidth by modality for each site.

Page 2

Page 3