© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-1 Understanding Bandwidth Provisioning Issues The Design Process—Planning

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-2 Supported Codecs G kbps G.729a8 kbps G kbps GSM kbps Intel Dialogic OKI ADPCM(32 kbps) 8 kHz Intel Dialogic OKI ADPCM(24 kbps) 6 kHz What Codecs Are Supported by Cisco Unity?

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-3 About G.711 Standard format for digital voice delivery in the PSTN Supported by Cisco, Intel Dialogic, all versions of Microsoft, and many other hardware and software platforms Best-quality codec Highest bandwidth—64 kbps and headers

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-4 About G.729a, G.726, and GSM 6.10 G.729a –Compressed voice to 8 kbps –Can be used on WAN links where limited bandwidth exists –Not supported natively in Windows Support can be added manually G.726 –Used with VPIM GSM 6.10 Smart phones

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-5 Voice-Message File Sizes and Audio Quality Ratings Audio CodecApproximate File Size, 1-Minute Message Quality Rating G.711 mu-law and a-law480 KBExcellent G kbps240 KBFine OKI ADPCM 8 kHz240 KBFine OKI ADPCM 6 kHz180 KBFine GSM KBGood G.729a60 KBGood

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-6 Codec Task List Choose a codec for recording and storage. Choose one or more codecs for message retrieval. Match Cisco Unity prompts and greetings to the codec chosen for recording and storage. If necessary use the Set WAV Format utility to change the format of recorded.wav files.

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-7 Network, Hardware, and Software Considerations for Choosing a Codec Audio CodecRecommended Deployment Situation Client Workstation Operating System Native Support ViewMail for OutLook or Lotus DUCs for Cisco Unity Additional Supported Hardware and Software G.711 mu-law and a-lawLAN Traditional PBX (unified messaging or voice messaging) without disk-space constraints Dual phone system environment WindowsNot requiredCisco Unified CallManager Cisco IP Phone 7960 Intel Diagnostic voice cards TTS output Microsoft NetMeeting G.729aWANCodec available from Cisco for Cisco Unity subscribers only Required, if codec is not installed on workstation Cisco Unified CallManager Cisco IP Phone 7960 TTS output OKI ADPCM 8 kHzTraditional PBX (unified messaging or voice messaging) with some disk- space constraints Codec available from CiscoRequired, if codec is not installed on workstation Intel Diagnostic voice cards OKI ADPCM 6 kHzTraditional PBX (unified messaging or voice messaging) with higher disk-space constraints Codec available from CiscoRequired, if codec is not installed on workstation Intel Diagnostic voice cards G KbpsFor use with VPIM Networking option; supported with Cisco Unity 4.0 and later with Exchange 2000 and with Cisco Unity 4.0(5) and later with Domino Codec available from third- party vendors Not required (codec must be installed on workstation) Cisco Unity Voice Connector for Microsoft Exchange 2000 GSM 6.10WANWindowsNot requiredGSM wireless handsets

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-8 DC/GC DDNS Exchange 2000 DC/GC DDNS Cisco Unity DC DDNS G.729a HeadquartersBranch WAN Cisco Unity and Bandwidth Issues Cisco Unified Call Manager1 Workgroup Cisco Unified Call Manager2

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-9 DC/GC DDNS Exchange 2000 DC/GC DDNS Cisco Unity DC DDNS G.729a Region 2 Region 1 Headquarters Branch WAN Example: Branch Office Client Access User at the branch office uses TUI to access Cisco Unity. Cisco Unity contacts domain controller to authenticate caller. Message is streamed from Exchange to Cisco Unity to the TUI. In ViewMail for OutLook, message is streamed to ViewMail client or downloaded first. Cisco Unified Call Manager1 Workgroup Cisco Unified Call Manager2

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-10 Transcoding Considerations for Choosing a Codec Minimize transcoding when possible to preserve audio quality. Use Cisco hardware resources for transcoding. Cisco Unity should not do all transcoding.

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-11 HeadquartersBranch Cisco Unity Cisco SRST Enabled If WAN is down, messages button can access Cisco Unity via the PSTN. WAN PSTN What Is the Cisco SRST Fallback Support for Branch Offices? Cisco SRST can be used to enable IP phones if connectivity is lost to the Cisco Unified CallManager. When in Cisco SRST mode, branch-to-headquarters calls use the PSTN. Voic access must be explicitly configured on the router. Cisco Unified Call Manager1 Workgroup Cisco Unified Call Manager2

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-12 Summary There must be adequate bandwidth to enable good-quality audio between all endpoints in the network. The codec selection guideline is that, if there is adequate bandwidth, G.711 is recommended. If compression is required to save bandwidth, G.729A is used. Intel Dialogic codecs are used with voice cards for PBX integrations. G.726 is used with VPIM integrations. Minimize transcoding when possible to preserve audio quality. If bandwidth is an issue, ViewMail for OutLook messages can be downloaded first and played back later. Cisco SRST can send and receive voic messages from Cisco Unity and other voic systems during Cisco Unified CallManager fallback.

© 2006 Cisco Systems, Inc. All rights reserved. CUDN v1.1—2-13