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| − | == |
+ | == Definitions == |
| + | === General === |
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| − | '''Jitter''' |
+ | '''Jitter''' is "[t]he time or phase difference between the [[data signal]] and the ideal [[clock]].<ref>[[NIST Special Publication 800-82]], at B-4.</ref> |
| + | '''Jitter''' is |
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| + | {{Quote|[t]he short-term phase variations of the significant instants of a [[timing signal]] from their ideal position in time (where short-term implies here that these variations are of [[frequency]] greater than or equal to 10 [[Hz]]).<ref>[[Framework for Cyber-Physical Systems]], at 13.</ref>}} |
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| + | === Packet switching === |
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| ⚫ | Jitter is often caused by low [[bandwidth]] situations in [[VoIP]] and can be exceptionally detrimental to the overall [[quality of service]]. Jitter can cause [[packet]]s to arrive and be processed out of sequence. When jitter is high, [[packet]]s arrive at their destination in spurts. This situation is analogous to uniform road traffic coming to a stoplight. As soon as the stoplight turns green ([[bandwidth]] opens up), traffic races through in a clump. The general prescription to control jitter at [[VoIP]] endpoints is the use of a [[buffer]], but such a [[buffer]] has to release its voice [[packet]]s at least every 150 ms (usually a lot sooner given the transport delay) so the variations in delay must be bounded. The [[buffer]] implementation issue is compounded by the uncertainty of whether a missing [[packet]] is simply delayed an anomalously long amount of time, or is actually lost. Jitter can also be controlled throughout the [[VoIP network]] by using [[router]]s, [[firewall]]s, and other [[network]] elements that support [[quality of service]]. These elements process and pass along time urgent [[traffic]] like [[VoIP]] [[packet]]s sooner than less urgent [[data]] [[packet]]s. |
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| + | '''Jitter''' |
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| + | * "as it relates to [[queuing]], is the difference in [[latency]] of [[packet]]s." |
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| ⚫ | '''Jitter''' is often caused by low [[bandwidth]] situations in [[VoIP]] and can be exceptionally detrimental to the overall [[quality of service]]. Jitter can cause [[packet]]s to arrive and be processed out of sequence. When jitter is high, [[packet]]s arrive at their destination in spurts. This situation is analogous to uniform road traffic coming to a stoplight. As soon as the stoplight turns green ([[bandwidth]] opens up), traffic races through in a clump. The general prescription to control jitter at [[VoIP]] endpoints is the use of a [[buffer]], but such a [[buffer]] has to release its voice [[packet]]s at least every 150 ms (usually a lot sooner given the transport delay) so the variations in delay must be bounded. The [[buffer]] implementation issue is compounded by the uncertainty of whether a missing [[packet]] is simply delayed an anomalously long amount of time, or is actually lost. Jitter can also be controlled throughout the [[VoIP network]] by using [[router]]s, [[firewall]]s, and other [[network]] elements that support [[quality of service]]. These elements process and pass along time urgent [[traffic]] like [[VoIP]] [[packet]]s sooner than less urgent [[data]] [[packet]]s. |
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== References == |
== References == |
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<references /> |
<references /> |
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| + | == Source == |
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| + | * [[NIST Special Publication 800-58]], at 20. |
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[[Category:Technology]] |
[[Category:Technology]] |
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[[Category:Definition]] |
[[Category:Definition]] |
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Latest revision as of 02:32, 18 March 2015
Definitions[]
General[]
Jitter is "[t]he time or phase difference between the data signal and the ideal clock.[1]
Jitter is
| “ | [t]he short-term phase variations of the significant instants of a timing signal from their ideal position in time (where short-term implies here that these variations are of frequency greater than or equal to 10 Hz).[2] | ” |
Packet switching[]
Jitter
- "refers to non-uniform packet delays that can cause packets to arrive and be processed out of sequence."
VoIP[]
Jitter is often caused by low bandwidth situations in VoIP and can be exceptionally detrimental to the overall quality of service. Jitter can cause packets to arrive and be processed out of sequence. When jitter is high, packets arrive at their destination in spurts. This situation is analogous to uniform road traffic coming to a stoplight. As soon as the stoplight turns green (bandwidth opens up), traffic races through in a clump. The general prescription to control jitter at VoIP endpoints is the use of a buffer, but such a buffer has to release its voice packets at least every 150 ms (usually a lot sooner given the transport delay) so the variations in delay must be bounded. The buffer implementation issue is compounded by the uncertainty of whether a missing packet is simply delayed an anomalously long amount of time, or is actually lost. Jitter can also be controlled throughout the VoIP network by using routers, firewalls, and other network elements that support quality of service. These elements process and pass along time urgent traffic like VoIP packets sooner than less urgent data packets.
References[]
- ↑ NIST Special Publication 800-82, at B-4.
- ↑ Framework for Cyber-Physical Systems, at 13.
- ↑ FCC, About the Consumer Broadband Test (Beta) (full-text).
Source[]
- NIST Special Publication 800-58, at 20.