Editing Voice over IP (section)

==Performance metrics==
The quality of voice transmission is characterized by several metrics that may be monitored by network elements and by the user agent hardware or software. Such metrics include network [[packet loss]], packet [[jitter]], packet [[round-trip delay time|latency]] (delay), post-dial delay, and echo. The metrics are determined by VoIP performance testing and monitoring.<ref>CableLabs, ''PacketCable Residential SIP Telephony Feature Definition'', Technical Report, PKT-TR-RST-V03-071106 (2007)</ref><ref>{{cite web
 | url         = http://www.it-innovations.ae/iit005/proceedings/articles/H_3_IIT05_Amin.pdf
 | title       = VoIP performance measurement using QoS parameters
 | date        = August 14, 2016
 | publisher   = A.H.Muhamad Amin
}}</ref><ref>{{cite web
 | url         = http://www.wseas.us/e-library/transactions/computers/2010/88-134.pdf
 | title       = Methodology for SIP Infrastructure Performance Testing
 | date        = August 14, 2016
 | publisher   = Miroslav Voznak, Jan Rozhon
}}</ref><ref>{{cite web
 | url         = http://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/voip-performance-vsphere5-white-paper.pdf
 | title       = Voice over IP (VoIP) Performance Evaluation on VMware vSphere® 5
 | date        = August 14, 2016
 | publisher   = VMware
}}</ref><ref>{{cite web
 | url         = http://startrinity.com/VoIP/TestingSipPbxSoftswitchServer.aspx
 | title       = Performance and Stress Testing of SIP Servers, Clients and IP Networks
 | date        = August 13, 2016
 | publisher   = StarTrinity
}}</ref><ref>{{cite web
 | url         = https://www.ixiacom.com/sites/default/files/resources/whitepaper/voip-whitepaper.pdf
 | title       = Testing Voice over IP (VolP) Networks
 | date        = August 14, 2016
 | publisher   = IXIA
}}</ref>