Delay and Jitter, Tandem Coding | Avaya 4600 Series specs

4600 Series IP Telephone LAN Administrator’s Guide

■Routing is related to addressing and allows connections to be established between endpoints.

Though these functions are common to data and voice networks, the implementations differ.

Delay and Jitter

Data traffic is generally short and comes in bursts. Data networks like the Internet were designed to manage these bursts of traffic from many sources on a first-come, first-served basis. Data packets are sent to multiple destinations, often without any attempt to keep them in a particular order.

Voice networks are designed for continuous transmission during a call. The traffic is not bursty, and the conversation uses a specific amount of bandwidth between the two ends for the duration of the call.

Several features of data networks are unsuitable for voice telephony:

■Data networks are designed to deliver data at the destination, but not necessarily within a certain time. This produces delay (latency). In data networks, delay tends to be variable. For voice messages, variable delay results in jitter, an audible chopiness in conversations.

■Variable routing also can result in loss of timing synchronization, so that packets are not received at the destination in the proper order.

■Data networks have a strong emphasis on error correction, resulting in repeated transmissions.

While data network concepts include prioritization of traffic types to give some forms of traffic greater reliability (for example, for interactive transactions), data requirements tend to be not as strict as most voice requirements.

Release 1.1 of the 4600 Series IP Telephones includes a dynamic jitter buffer. This feature automatically smooths jitter to improve audio quality.

Tandem Coding

Tandem coding (also called transcoding) refers to the conversion of a voice signal from analog to digital and back again. When calls are routed over multiple IP facilities, they may be subject to multiple transcodings. The multiple conversions between analog and digital coding result in a deterioration in the voice quality. Tandem coding should be avoided wherever possible in any compressed voice system (for example, minimizing analog trunking on the PBX).

Overview of Voice over IP

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Avaya 4600 Series manual Delay and Jitter, Tandem Coding

Contents

Series IP Telephone Page Avaya Web Obtaining Products European Union Declaration of Conformity Series IP Telephone LAN Administrator’s Guide Table of Contents Requirements Troubleshooting Guidelines Appendix C Creating Websites for the 4620 IP Telephone About This Guide Intended Audience Document Organization Change History Terms Used in This Guide ARP Symbolic Conventions Conventions Used in This GuideTypographic Conventions Online Documentation Related Documents Definity Documentation Release Ietf Documents IP Telephone User Guide 555-233-765 Int’l ITU Documents Customer Support ISO/IEC, ANSI/IEEE Documents Introduction Overview of Voice over IPData and Voice Network Similarities Delay and Jitter Tandem Coding Voice Coding Standards Standard NAT QoS Suggestions for Installation and Configuration Network AssessmentReliability and Performance IP Address Lists and Station Number Portability Security Series IP Telephones Initialization Process Telephone to NetworkDhcp Server to Telephone Telephone and Tftp Server Telephone and the Definity /MultiVantageTM Call ServerPage Requirements Hardware Requirements Refer to the 4600 Series IP Telephone Installation Guide Software Requirements Sample Configuration Using 4600 Series IP Telephones Server Administration Dhcp Vlan 4600 IP Telephone Installation Guide Sson Dhcp Dhcp and Tftp Definity ReleaseDefinity Releases 9, 9.5, 10, and MultiVantageTM Software Checklist Required Network Information Choosing a Dhcp Configuration Dhcp Software Alternatives Dhcp Generic Setup Dhcp Dhcpack Setting of System Values Set to Verifying the Installation of the Dhcp ServerInitial Configuration Select Start-Settings-Control Panel Select Scope-Create Select Start-Programs-Admin Tools-DHCP ManagerCreating a Dhcp Scope for the IP Telephones Example Adding the Dhcp Option Select Dhcp Options-Defaults in the menuEditing Custom Options Click Edit Array Select Defaults from the DHCPOptions menu Verifying Your ConfigurationVerify the Default Option, 176 46XXOPTION Activating the Leases Windows 2000 Dhcp Server Creating and Configuring a Dhcp ScopeSelect Start-Programs-Administrative Tools-DHCP Verify the Global Option, 176 46XXOPTION Example Adding Dhcp Options Activating the New Scope Avaya Tftp Suite Pro Tftp Generic SetupConfiguration Tftp Select System-Setup Series IP Telephone Scripts Application Files Contents of the Upgrade Script QoS Ieee 802.1D and 802.1Q Diffserv UDP Port Selection QoS with 4620 and 4630 IP TelephonesParameter Possible Values Rsvp and Rtcp Administering Options for the 4600 Series IP Telephones DNS Addressing Customizing the Site-Specific Option Number Sson Entering Options via the Telephone Dialpad Mcport Customizing the 4630 IP TelephoneL2QVLAN PHY2STAT Directory Application Parameters Parameter Name Default Value Status Range Stock Ticker Application ParametersVoice Mail Application Parameters Web Access Application Parameters Webcoding Ascii Backup/RestoreBackup/Restore Parameters Ftpsrvr Setting/Parameter Name Type Call Log Archive Customizing the 4620 IP Telephone Wmlexcept WmlhomeWmlproxy Wmlport Wmlcoding Ascii Troubleshooting Guidelines Error Conditions Series IP Telephone LAN Administrator’s Guide Resolution As above Resolution Use the softkey Menu Resolution Series IP Telephone LAN Administrator’s Guide Refer to of the 4600 Series IP Telephone Installation Guide View Administrative Option Mute 8 4 3 9 # Mute V I E W # Error Messages Filename2.exe Detailed in the 4600 Series IP Telephone Installation Guide During Registration Series IP Telephone LAN Administrator’s Guide Troubleshooting Guidelines Series IP Telephone LAN Administrator’s Guide Error Messages From RFC1213-MIB LAST-UPDATEDDefinitions = Begin Imports Organization OBJECT-TYPE SyntaxStatus Page Syntax Octet String Page Page Page Page Page Page Page Page Page Page Page Page Page Stored in NVM. = endptNVM Page Page Page Syntax Integer Status Page Syntax Octet String Audio, currently in use. = endptDEFINITY Page Page Syntax Integer Obsolete Avaya 46xx IP Telephone MIB EndptDIRSRVR OBJECT-TYPE Syntax Integer Page EndptFTPSRVR Syntax Integer Page Avaya 46xx IP Telephone MIB EndptWEBPROXY OBJECT-TYPE Page Page Syntax Octet String END Page Appendix B Creating Websites for the 4630 IP Telephone General Background Browser Features and Behavior Document Skeleton Content-Based Style Logical Style Physical Style Physical Spacing and Layout Lists and TablesLists Tables Images Links Frames Forms Character Entities ColorsFonts Design Guidelines CookiesFixed-Width Objects Images Maintaining Context User Interaction Appendix C Creating Websites for the 4620 IP Telephone Comments WML Document SkeletonAttribute Not Supported Onenterbackward Url Occurs when the user Text Elements Attribute Value Description CommentsSupported Text Formatting Tags Anchor Elements Image Elements Px pixel Event Elements Type Description Comments Type Default Label if no label Specified Event Permitted Tags Description Task Elements Required Supported Input Elements Nmtoken Number Sets a title for Variable Elements Description Symbol Numeric Entity Name Entity Character Entities Colors and Fonts Summary Of WML Tags And AttributesTag Attribute Supported? Align Alt Ivalue