Jitter in networking is the time delay between packets that are being sent over a network connection
Whenever data packets are transmitter from a source to a destination, these data packets ideally should arrive in regular intervals of time
However in the real world, there are many factors that influence these packets and can cause dealy in arrival, these factors include congestion on the network, routing decisions and hardware issues
This leads to uneven data flow on the network, Jitter is an important metric especially in scenarios where real time communication is involved and where the consistancy in timing is very important for quality of service for a product
These includes real time services and products such as chat and video calls and streaming
How does Jitter differ from Latency and Packet Loss
In this section we are going to learn how does the Jitter differ from latency and packet loss
- latency: This is also called as Ping. Latency is the round trip time it takes a packet of data to travel from one source to destination.
Latency represents the overall delay experieced in the network as compared to jitter which is a measure of variability in the packet delay
If a server is geographically far away from a client the client will experience latency but if the networking equipment is good and there in no congestion in the network then the packets of data will arrive at regular intervals of time and there will be no jitter in the network
If you like to learn more about latency and what factors affect latency, you can refer to our article: What is low Latency?
- Packet Loss: Packet loss occours when more and more data packets do not reach their destination
Key Concepts related to Jitter
- Packet Delay Variance
is another term for Jitter, it quantifies the delay between packet and the time between them. A high packet delay varience means a high levels of jitter.
- Real time Packet Streaming
This is the transmission of data packets that are processed in real time such as in real time video streaming
For use cases where there is a need for real time packet streaming it is nessessory to keep jitter at bay. Maintaining a low jitter ensures that the stream is stable
High jitter can result in issues such as out of sync audio and video or poor video quality
- Quality of Service
There are network mechanisms that prioritize traffic that needs real time packet streaming anf use cases where low jitter is necessary good performance
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What are Jitter Buffers
Jitter buffers as the name suggests are small temporary storage areas in network devices and software applications, that collect incoming packets of data from the internet
The packets of data are then stored for a short period and then send to the CPU in evenly spaced time intervals to smoothen out the jitters in the video or any other application
Thus counteracting the effects of jitter in packet switched network by smoothing out the packet arrival times.
This is how the complete process of Jitter buffers work
Packets arrive at a devices in varying intervals, this is due to bad network conditions. The jitter buffers collects the packets in the storage space and smoothen out the flow of packets to the cpu, they also put in squence the packets that arrive out of sequence and thus compensates the jitter.
Types of Jitter Buffers
1. Static Jitter buffer
The static Jitter buffer has a fixed size and delay capacity, these are set during the designing of the network application.
The delay buffer is set on the estimated network conditions and set when designing the system and it will not adapt to changing network environment
This is easier to implement but the drawback is that if the jitter storage capacity exceeds packet loss will occur leading to degraded service quality
And if the jitter is considerably less than anticipated then the delay introduced by the jitter buffer will create unnessesory latency in the system
2. Dynamic Jitter Buffer
The dynamic jitter buffers are sofisicated buffers in the sense that they can dynamically change their size and delay in response to varying network conditions
The system contineously analyses the incoming packet flow and adapt the jitter buffer to optimize the trade off between latency and smooth playback
This featuers makes dynamic jitter buffers most useful in different types of network cinditions where it is impossible to determine the fluctuations in the network
The one downside of dynamic jitter buffers is that they are difficult to implementand require processing power to analyse network conditions and dynamically adjust the buffer size with varying network packet flow data
Measuring and Analysing Jitter
Tools for Jitter Measurement
Jitter measurement is important for diagnosing network performance and ensuring the reliability of real time apps such as VoIP and video streaming
Network Analyzers
Hardware Based Analyzers: These are phycical devices that are connected to a network and monitor incoming traffic and analyse packet flow and timing
These provide real time insights into jitter levels by capturing the incoming traffic data and analysing the timing between packets and their variations
Some of the well know brands include NetScout and keysight and tecktronics etc
Software Based Analysers: Software can be installed on routers or servers to analyse the network traffic same as hardware baed systems. The main differenciator is that the software based use router or server resources to perform the functions such as memory, disk space and cpu resources
whereas the hardware based onces does not affect the servers and routers in any form.
An example of the software based tool is wireshark that allows for packet inspection and can be used to determine jitter levels.
Key Metrics for Accessing Jitter In a Network
Jitter Value
this is measured in milliseconds, the jitter valus is the average or the peak variance in packet delay
For most applications the jitter value of 30 ms is acceptable but 10 ms or less is ideal.
Packet Delay Variance (PDV)
PDV is a way of expressing jitter, it is a statistical measure of variability in packet delay and is used in detailed network analysis in order to understand the distribution and frequency of delay variance.
Quality of service (QoS)
There are other metrics other than jitter that are also essential in maintaining network quality.
these include packet loss, bandwidth and latency
These metrics provide a comprehensive network overview, the Service Level Agreements that are signed between companies often specify these metrics including jitter to ensure network services.
Interarrival Jitter
The interarrival Jitter is often calculated by routers, this is the mean deviation of the delay between consecutive packets of data coming from the network.
This is specially important in understand how the jitter is impacting the RTP streams which are critical in VoIP and video streaming services
Short term and Immediate Strategies to Reduce Jitter
Immediate Steps to Reduce Jitter
Upgrading to Modern Routers
- Enhanced Processing Power
There are newer routers that have much more powerful processing power and memory that allow then to handle higher throughput without causing delays and thus reducing Jitter
- Advanced QoS capabilities
Most modern routers have powerful processors that can implement complex Quality of service rules that can prioritize based on type of application that is using the internet
The prioritization is important for services such as VoIP and video calling application also real time applications that need low Jitter and and high bandwidth application
- Better firmware software support
Updated modern networking equipment has the latest software updates and optimizations that can help reduce jitter
These updates provide new features and enhance the packet management and improve network infrastructure
Implementing QoS
- Traffic prioritization
Network administrators can improve the quality of network and reduce jitter by prioritizing communication and real time traffic.
- Bandwidth Allocation
Quality of Service rules can also allocate bandwidth based on the applications in order to prevent network congestion and maintain smooth flow of internet traffic
More bandwidth can be assigned to applications that require real time network such as video calling and streaming.
Web browsing and other such applications can be put on a low priority
Network monitoring tools
- Continuous Monitoring
You can implement contineous monitoring with network monitoring tools. These tools monitor factors such as traffic flow, bandwidth usage, latency and jitter levels.
- Automated Alerts
In the same tools you can implement automated alerts as well. You can set what network parameters are important to you and then you can set that when these parameters are reached the automated alerts are triggers
for example you can set jitter levels at 30 ms and if they are reached the automated alerts will trigger.
Pinpointing sources of Jitter
You can also pinpoint the sources of Jitter using traffic analyses and find what if some specific devices are causing jitter in your network
you can also compare current performance against some pre set bandmark that you can determine would be best for the applications that you are running
Longer term strategies to reduce Jitter
Network design optimization
Efficient Routing:
Designing a network topology that reduces bottlenecks and ensuring proper data routing can reduce latency and jitter in the network
This might involve seeing that network routes are proper and that there are fewer hops between devices and that high demand users are segmented in order to prevent other users traffic from getting affected
Redundancy:
Implementing redundancy such as with having multiple ISP and routers and backup electricity can reduce jitter, if some pathway or ISP is not working properly then the network can be swithed to work with other ISP
Service Provider Assessment
Assessing a ISP before signing them on is crucial in order to get a bettter internet experience
You should study the market and evalutate different ISPs before coming to a conclusion as to which one is the best in network infrastructure
You can also sign Service level agreements with the ISP in order to get gauranteed internet experience from them.
Common Causes of Jitter
Network congestion
Network congestion happens where there is too much traffic going through a network and it exceeds the capacity of the network to handle the traffic
This can result in excessive latency packet loss and jitter
- Bandwidth saturation: look at bandwidth as a pipe with traffic flowing through it like water.
The pipe has a capacity that is the rate of water that can flow through it per unit of time
If the rate exceeds then packets of data must wait for their turn to be transmitted thus introducing lateny and jitter in the network
- Real time applications
For apps such as video calling and VoIP even minor delays in packet transmission caused by congestion can lead to poor quality of user experience, this is because the packets of data do not arrive at predictable intervals in time
- Resolution strategies
To optimize the network and reduce congestion, network adminstrators can increase network bandwidth, prioritize traffic using QoS rules and monitor traffic to better understand and manage peak usage times
Inadequate hardware and firmware issues
Older networking devices like routers and switches can cause significant network jitter, these devices might not have the proper processing power and software upgrads to handles todays networking needs and as such need to be replaced in order to get the most out of your internet connection
External Interferences
External interferences can cause issues in wireless networks, these can be a significant source of jitter
- Wireless signal interference
In wireless networks and devices such as mobile phones and wifi enabled devvices there can be interference from other wifi routers and devices
This interference weakens or distorts the wifi signals thus causing interference and leading to issues such as jitter and latency
- Physical Obstructions
Phycical Obstructions such as a wall or phycical distance between the wifi routers and the devices can also cause variability in the signal strength and transmission speed of data
- Environmental factors
Environmental factors such as electrical interference can alsoc cause network interference and lead to increased latency and reduction in the bandwidth capacity plus increased jitter
Impact of Jitter on Businesses and Apps
Voice over Internet Protocol (VoIP) and video calling
VoIP and video calling requires a steady stream of packets in order to maintain a clear audio and video experience.
Jitter causes the packets of data to arrive at uneven intervals of time, thus high jitter can degrade the quality of service such as dropped audio and choppy video which can disrupt the call quality