This document provides information about network latency, packet loss, and jitter. It defines these terms and discusses their causes and effects. It also provides tips on diagnosing and addressing issues, including performing ping and traceroute tests, using network monitoring tools, and optimizing hardware, software, bandwidth and network configuration. The overall goal is to help readers understand these network performance issues and how to improve latency, packet handling, and the end user experience.
The document discusses common network problems such as high bandwidth usage slowing download speeds, high CPU usage degrading network performance, and physical connectivity issues with defective cables. It provides examples of specific causes for each type of problem like video streaming consuming bandwidth, large applications increasing CPU usage, and damaged fiber optic cables reducing data transfer speeds. The document also covers other frequent network issues involving malfunctioning devices, DNS errors preventing access to websites, and wireless interference weakening WiFi signals.
White Paper: Accelerating File TransfersFileCatalyst
Check out our White Paper on Accelerating File Transfers
Increase File Transfer Speeds in Poorly-Performing Networks for an understanding of the issues associated with transferring files over the TCP/IP protocol (i.e. using FTP) and how to solve these problems with file transfer acceleration.
CASE STUDY FOR PERFORMANCE ANALYSIS OF VOIP CODECS IN NON-MOBILITY SCENARIOSijcsity
IEEE 802.11 is the most popular standard for WLAN networks. It offers different physical transmission
rates. This paper focuses on this multi transmission rate of 802.11 WLANs and its effect on speech quality.
In non-adaptive systems, when the physical layer switches from a higher transmission rate to a lower one,
different than the one that the VoIP flow needs, the switching may result in congestion, high delay and
packet loss, and consequently speech quality degradation. However, there are some algorithms that adapt
the transmission parameters according to the channel conditions. In this study we demonstrate how
choosing parameter (different codec and packet size) can affect the voice quality, network delay and packet
loss. Further, this study presents a comparison between adaptive and non-adaptive methods. The adaptive method has also been evaluated for different congestion level from perceived speech quality point of view.
Testing firewalls can be an exact science. Learn how Fortinet tests their firewalls using BreakingPoint. This presentation details how to test firewalls with real-world application traffic, load, and live security attacks. This presentation was given by Fortinet in the BreakingPoint booth at Interop 2011 and included their announcement of the FortiGate 3950B's Resiliency Score of 95, the highest ever published.
This document discusses network application performance and ways to improve it. It covers topics like delay, throughput, jitter, quality of service (QoS), and performance measurement tools. Key points include identifying various sources of delay like processing, retransmissions, queueing, and propagation. It also discusses transport protocols TCP and UDP, and ways to optimize TCP performance through techniques like jumbo frames, path MTU discovery, window scaling, and selective acknowledgements. The roles of different network stakeholders in ensuring good performance are also mentioned.
Shunra university 1 intro to network virtualizationAmichai Lesser
This document discusses network virtualization and summarizes key concepts around network performance testing. It notes that current performance testing does not adequately model the diverse real-world network conditions users experience. Specifically, it states that testing is typically done from high-speed lab networks, whereas users connect via various networks including 3G, LTE, WiFi and broadband with differing bandwidth and latency characteristics. The document advocates for using network virtualization technology to simulate diverse user environments and more comprehensively test the impact of network conditions on performance and user experience.
1) IP telephony uses RTP/UDP/IP to transport voice data over IP networks in order to allow for packet loss and variable delay while still delivering voice packets in order.
2) RTP provides mechanisms for delivering audio and video over IP networks by encapsulating media streams in UDP packets and providing sequence numbering and time-stamping to enable synchronization and loss detection.
3) Key challenges for delivering voice over IP include delay, jitter, packet loss, echo, and the need for voice activity detection and compression to efficiently use available bandwidth.
The document discusses common network problems such as high bandwidth usage slowing download speeds, high CPU usage degrading network performance, and physical connectivity issues with defective cables. It provides examples of specific causes for each type of problem like video streaming consuming bandwidth, large applications increasing CPU usage, and damaged fiber optic cables reducing data transfer speeds. The document also covers other frequent network issues involving malfunctioning devices, DNS errors preventing access to websites, and wireless interference weakening WiFi signals.
White Paper: Accelerating File TransfersFileCatalyst
Check out our White Paper on Accelerating File Transfers
Increase File Transfer Speeds in Poorly-Performing Networks for an understanding of the issues associated with transferring files over the TCP/IP protocol (i.e. using FTP) and how to solve these problems with file transfer acceleration.
CASE STUDY FOR PERFORMANCE ANALYSIS OF VOIP CODECS IN NON-MOBILITY SCENARIOSijcsity
IEEE 802.11 is the most popular standard for WLAN networks. It offers different physical transmission
rates. This paper focuses on this multi transmission rate of 802.11 WLANs and its effect on speech quality.
In non-adaptive systems, when the physical layer switches from a higher transmission rate to a lower one,
different than the one that the VoIP flow needs, the switching may result in congestion, high delay and
packet loss, and consequently speech quality degradation. However, there are some algorithms that adapt
the transmission parameters according to the channel conditions. In this study we demonstrate how
choosing parameter (different codec and packet size) can affect the voice quality, network delay and packet
loss. Further, this study presents a comparison between adaptive and non-adaptive methods. The adaptive method has also been evaluated for different congestion level from perceived speech quality point of view.
Testing firewalls can be an exact science. Learn how Fortinet tests their firewalls using BreakingPoint. This presentation details how to test firewalls with real-world application traffic, load, and live security attacks. This presentation was given by Fortinet in the BreakingPoint booth at Interop 2011 and included their announcement of the FortiGate 3950B's Resiliency Score of 95, the highest ever published.
This document discusses network application performance and ways to improve it. It covers topics like delay, throughput, jitter, quality of service (QoS), and performance measurement tools. Key points include identifying various sources of delay like processing, retransmissions, queueing, and propagation. It also discusses transport protocols TCP and UDP, and ways to optimize TCP performance through techniques like jumbo frames, path MTU discovery, window scaling, and selective acknowledgements. The roles of different network stakeholders in ensuring good performance are also mentioned.
Shunra university 1 intro to network virtualizationAmichai Lesser
This document discusses network virtualization and summarizes key concepts around network performance testing. It notes that current performance testing does not adequately model the diverse real-world network conditions users experience. Specifically, it states that testing is typically done from high-speed lab networks, whereas users connect via various networks including 3G, LTE, WiFi and broadband with differing bandwidth and latency characteristics. The document advocates for using network virtualization technology to simulate diverse user environments and more comprehensively test the impact of network conditions on performance and user experience.
1) IP telephony uses RTP/UDP/IP to transport voice data over IP networks in order to allow for packet loss and variable delay while still delivering voice packets in order.
2) RTP provides mechanisms for delivering audio and video over IP networks by encapsulating media streams in UDP packets and providing sequence numbering and time-stamping to enable synchronization and loss detection.
3) Key challenges for delivering voice over IP include delay, jitter, packet loss, echo, and the need for voice activity detection and compression to efficiently use available bandwidth.
This is the subject slides for the module MMS2401 - Multimedia System and Communication taught in Shepherd College of Media Technology, Affiliated with Purbanchal University.
Microsoft RemoteFX promises to enhance the user QoE for rich media applications running on remote desktops and IPQ can be a key technology to help deliver on that promise.
1. The document discusses various networking devices like hubs, bridges, switches and routers. It explains their functions such as hubs being basic devices that connect computers without intelligence, bridges operating at data link layer to interconnect LANs, switches being intelligent devices that divide collision domains, and routers dividing broadcast domains and routing packets based on IP addresses.
2. It then discusses types of delays in packet switched networks including processing, queuing, transmission and propagation delays and how they accumulate. It also discusses causes of packet loss like link congestion, over-utilized devices, faulty hardware/software, and differences between wired and wireless networks.
3. Finally, it compares circuit switching which establishes dedicated connections and packet switching
Practical Fundamentals of Voice over IP (VoIP) for Engineers and TechniciansLiving Online
This manual provides solid practical advice on application, implementation and, most importantly, troubleshooting Voice Over IP (VOIP) systems.
MORE INFORMATION: http://www.idc-online.com/content/practical-fundamentals-voice-over-ip-voip-21?id=151
Individual CommentsYour answers missed there below topics, sp.docxdirkrplav
Individual Comments:
Your answers missed there below topics, spend a little more time on the format of your answers
question 1 - backward compatibility?, scalability?
question 2 - success rate?, reliability?
question 3 - QoS?, Security?
question 4 - foreign agent?
1. Why did Ethernet become an acceptable LAN standard?
Be specific in your explanation.
Many factors funded to Ethernet by becoming a LAN standard, the first factor is that Ethernet is reliable by using CSMA/CD to sense before sending any data to the network to avoid crash, and in this case the crash detection method stop all transmission and assigns a random retransmission delay time to all nodes. The second factor is the management tools that are available to manage the Ethernet using SNMP from a central location. The third factor is Ethernet trouble shooting is easy by using easy ways for example the light indicator or a more sophisticated way like using a network analyzer. The fourth reason is that Ethernet has a low cost comparing it to other technologies that the user doesn't need to buy extra hardware and can connect it directly depending on his computer network. On the other hand, it doesn’t have a security issue such as wireless networks which has risk through the airwaves, but, users should have good security desktop application to prevent unapproved accesses.
2.From the users point of view how does one measure network performance?
The network performance is identified commonly in bites per seconds. It can be measured by multiple factors which are bandwidth, throughput, latency and error rate and from those factors the bandwidth is the maximum rate that data can be transferred with, Latency is the delay between the sending and receiving. Error rate is the percentage of corrupted data that is being sent. There are three main possible ways to measure: the first one is the total of bytes transferred (from server to the user and opposite) in one session which can be used to measure the overhead of protocol (bandwidth). Second ways, number of round trips in one operation (transaction). Third point, time taken to pull or push from network bandwidth and ping time. Moreover, the user could measure network performance in normal way by trying to copy a file over the network depending on the file transferring time; furthermore, he could gauge the speed by the time it takes for a file to copy from or to the network.
3.Why did IPv4 prevail for such a long time and why the change to IPv6?
Shifting for IPv4 to IPv6 requires a huge investment of human and capital resources. While, it doesn’t provide a clear picture of the short-term return which resulted the enterprises to frequently postpone this investment. However the time came to change from IPv4 to IPv6. IPv4 provide maximum of about 4 billion addresses whereas IPv6 has an unthinkable theoretical maximum: about 340 trillion, trillion, trillion addresses. Previously (with IPv4) home user got a single user, while the IPv4 pro.
Mohammad Faisal Kairm(073714556) Assignment 2mashiur
This document discusses implementing IP telephony over traditional PSTN and PLMN networks to reduce transmission costs. It proposes replacing TDM connections between exchanges with an IP backbone using voice compression to utilize the full bandwidth of E1 circuits. Some challenges of implementing an IP backbone for voice include ensuring sufficient network quality by limiting packet loss, jitter, and latency to avoid voice quality issues like dropouts and echo. Overall, IP telephony could lower costs through more efficient use of existing infrastructure and management capabilities.
This document summarizes the study of parameters that determine the quality of service of various Voice over IP (VoIP) clients. The study measured parameters like bandwidth requirement, delay, packet size and observed how clients behaved under different network conditions. Key findings were that bandwidth, jitter, latency and packet loss most affected quality of service. The VoIP clients tested included Google Talk, Skype, VQube, Windows Live Messenger and Yahoo Voice Messenger. Network Address Translation (NAT) types and Simple Traversal of UDP through NAT (STUN) were also explained.
National Diploma Unit 08 Communication Technology Assignment 2 Support Material provides information on communication protocols and wireless technology. It explains the principles of signal theory and describes common communication protocols like TCP/IP and Bluetooth. It discusses how digital signals are represented as strings of zeros and ones. The document also covers wireless LAN protocols like 802.11a, 802.11b, and 802.11g and security protocols like WEP and WPA. It provides examples of wireless technologies in use such as mobile phones, WiFi, and infrared communications.
The document discusses quality of service (QoS) concepts in computer networking. It begins by defining QoS and explaining the need to classify different types of network application traffic, such as voice, video, and data. It then covers various QoS techniques including traffic characterization, queuing algorithms like weighted fair queuing and low latency queuing, and QoS models like integrated services and differentiated services. The document is intended to provide an overview of key QoS concepts for computer networking students.
Watch the full OnDemand Webcast: http://bit.ly/tuneupnetwork
It’s time to make good on that new year’s resolution. Admit it, in a moment of weakness as the clock hit midnight you resolved to dig in and tune up your corporate network in the new year. Well, the new year is already passing quickly by, so if you haven’t yet made good on that resolution, here is your chance. In these slides from our web seminar, we return to the basics – overall network evaluation, baseline measurements and comparisons, typical yet troublesome network issues, sharing bandwidth in the presence of time-sensitive applications, security, and overall network monitoring and reporting, just to name a few. We focus on practical issues and practical methods for improving the overall health of your network.
In these slides, we will cover:
- Critical elements to consider when evaluating your network
- Common pitfalls and how to avoid them
- Developing and using network baselines
- Optimizing network usage in the presence of competing applications and protocols
- Monitoring and reporting on your well-tuned network
What you will learn:
1. How and where to find the data you need
2. How to automate network monitoring and analysis to ensure the success of your tune up
3. How to quickly diagnose problems when things go wrong
Boost your internet experience with the ultimate WiFi Speed Test tool. Discover the true potential of your connection by measuring its speed, reliability, and performance effortlessly. Whether you're a casual user, a gamer, or a professional, this SEO-friendly WiFi Speed Test provides accurate results in seconds. Identify bottlenecks, optimize your network settings, and ensure seamless browsing, streaming, and downloading. Stay ahead of the curve and elevate your online activities with this reliable and efficient WiFi Speed Test.
Simplified Networking and Troubleshooting for K-12 Teacherswebhostingguy
The document provides an overview of networking concepts and troubleshooting tips for K-12 teachers. It discusses common network topologies including star and backbone networks. It also describes network components like hubs, switches, routers and servers. Basic networking concepts such as the OSI model, TCP/IP, IP addressing, subnets, and DNS are explained. Finally, the document provides steps to troubleshoot common issues like no internet access, email problems, printing issues, and joining a domain.
This document discusses quality of service (QoS) requirements for voice over IP (VoIP) and how QoS can be implemented in packet switched networks to address issues like jitter, latency, bandwidth congestion, and packet loss that can negatively impact call quality. It explains that QoS aims to guarantee a certain level of performance for applications like VoIP through techniques like traffic classification, marking, and queuing. The document also provides recommendations for applying QoS on the network edge, core, and internet exchange points to help improve end-to-end call quality.
TECHNICAL WHITE PAPER: NetBackup Appliances WAN OptimizationSymantec
In a world of ever increasing data flow as well as globalization of data centers the effectiveness and utilization of the networks connecting sites is of the highest importance to end users. Even with network enhancement and improvement, the ability of the infrastructure to keep pace with the flow of data has proved not to be in lockstep. To optimize the flow of data verses increasing the pipe that is flows along is seen as critical to keeping operations running and costs minimal. This paper discusses the new WAN Optimization technology that has been introduced in the NetBackup 5220 and 5020 appliances.
This document outlines the WAN Optimization feature enhancements introduced on the NetBackup 5220 and NetBackup 5020 and applies to:
• NetBackup 5220 & 5230 appliances with version N2.5 and above installed
• NetBackup 5020 & 5030 appliances with version D1.4.2 and above installed
Factors which affect the speed of internet computer studies lessonMukalele Rogers
There are several factors that can affect the speed of an Internet connection, including computer processor speed, distance data must travel, network traffic levels, malware/viruses, modem speed, natural conditions, positioning of modems and routers, hardware and software problems, available memory, computer settings, technical issues, and cookies. Addressing these common factors can help optimize connection speed.
Introduction to computer networks ppt downloadzanetorserwaah
This presentation provides an introduction to computer networks. It discusses the definition of a computer network and reasons for networking computers, including sharing information, hardware, software, and centralized administration. It covers different types of networks based on transmission media, size, management method, and topology. Specific topics covered include LANs and WANs, peer-to-peer and client/server networks, common network topologies, transmission media, protocols, network operating systems, and a brief history of the Internet.
This document contains details about the computer networks course subject code EC8551, including:
- Requirements to build a computer network such as computers, network interfaces, switches, hubs, routers, and cables.
- Metrics that influence network performance such as bandwidth, throughput, latency, data loss, and errors.
- Key concepts like bandwidth, latency, error detection, error correction, framing, flow control, and more.
- Differences between circuit switched and packet switched networks.
- Services provided by the data link layer such as framing, reliable delivery, and error detection.
- Parameters used to measure network performance including bandwidth, throughput, latency, and error rate.
This is the subject slides for the module MMS2401 - Multimedia System and Communication taught in Shepherd College of Media Technology, Affiliated with Purbanchal University.
Microsoft RemoteFX promises to enhance the user QoE for rich media applications running on remote desktops and IPQ can be a key technology to help deliver on that promise.
1. The document discusses various networking devices like hubs, bridges, switches and routers. It explains their functions such as hubs being basic devices that connect computers without intelligence, bridges operating at data link layer to interconnect LANs, switches being intelligent devices that divide collision domains, and routers dividing broadcast domains and routing packets based on IP addresses.
2. It then discusses types of delays in packet switched networks including processing, queuing, transmission and propagation delays and how they accumulate. It also discusses causes of packet loss like link congestion, over-utilized devices, faulty hardware/software, and differences between wired and wireless networks.
3. Finally, it compares circuit switching which establishes dedicated connections and packet switching
Practical Fundamentals of Voice over IP (VoIP) for Engineers and TechniciansLiving Online
This manual provides solid practical advice on application, implementation and, most importantly, troubleshooting Voice Over IP (VOIP) systems.
MORE INFORMATION: http://www.idc-online.com/content/practical-fundamentals-voice-over-ip-voip-21?id=151
Individual CommentsYour answers missed there below topics, sp.docxdirkrplav
Individual Comments:
Your answers missed there below topics, spend a little more time on the format of your answers
question 1 - backward compatibility?, scalability?
question 2 - success rate?, reliability?
question 3 - QoS?, Security?
question 4 - foreign agent?
1. Why did Ethernet become an acceptable LAN standard?
Be specific in your explanation.
Many factors funded to Ethernet by becoming a LAN standard, the first factor is that Ethernet is reliable by using CSMA/CD to sense before sending any data to the network to avoid crash, and in this case the crash detection method stop all transmission and assigns a random retransmission delay time to all nodes. The second factor is the management tools that are available to manage the Ethernet using SNMP from a central location. The third factor is Ethernet trouble shooting is easy by using easy ways for example the light indicator or a more sophisticated way like using a network analyzer. The fourth reason is that Ethernet has a low cost comparing it to other technologies that the user doesn't need to buy extra hardware and can connect it directly depending on his computer network. On the other hand, it doesn’t have a security issue such as wireless networks which has risk through the airwaves, but, users should have good security desktop application to prevent unapproved accesses.
2.From the users point of view how does one measure network performance?
The network performance is identified commonly in bites per seconds. It can be measured by multiple factors which are bandwidth, throughput, latency and error rate and from those factors the bandwidth is the maximum rate that data can be transferred with, Latency is the delay between the sending and receiving. Error rate is the percentage of corrupted data that is being sent. There are three main possible ways to measure: the first one is the total of bytes transferred (from server to the user and opposite) in one session which can be used to measure the overhead of protocol (bandwidth). Second ways, number of round trips in one operation (transaction). Third point, time taken to pull or push from network bandwidth and ping time. Moreover, the user could measure network performance in normal way by trying to copy a file over the network depending on the file transferring time; furthermore, he could gauge the speed by the time it takes for a file to copy from or to the network.
3.Why did IPv4 prevail for such a long time and why the change to IPv6?
Shifting for IPv4 to IPv6 requires a huge investment of human and capital resources. While, it doesn’t provide a clear picture of the short-term return which resulted the enterprises to frequently postpone this investment. However the time came to change from IPv4 to IPv6. IPv4 provide maximum of about 4 billion addresses whereas IPv6 has an unthinkable theoretical maximum: about 340 trillion, trillion, trillion addresses. Previously (with IPv4) home user got a single user, while the IPv4 pro.
Mohammad Faisal Kairm(073714556) Assignment 2mashiur
This document discusses implementing IP telephony over traditional PSTN and PLMN networks to reduce transmission costs. It proposes replacing TDM connections between exchanges with an IP backbone using voice compression to utilize the full bandwidth of E1 circuits. Some challenges of implementing an IP backbone for voice include ensuring sufficient network quality by limiting packet loss, jitter, and latency to avoid voice quality issues like dropouts and echo. Overall, IP telephony could lower costs through more efficient use of existing infrastructure and management capabilities.
This document summarizes the study of parameters that determine the quality of service of various Voice over IP (VoIP) clients. The study measured parameters like bandwidth requirement, delay, packet size and observed how clients behaved under different network conditions. Key findings were that bandwidth, jitter, latency and packet loss most affected quality of service. The VoIP clients tested included Google Talk, Skype, VQube, Windows Live Messenger and Yahoo Voice Messenger. Network Address Translation (NAT) types and Simple Traversal of UDP through NAT (STUN) were also explained.
National Diploma Unit 08 Communication Technology Assignment 2 Support Material provides information on communication protocols and wireless technology. It explains the principles of signal theory and describes common communication protocols like TCP/IP and Bluetooth. It discusses how digital signals are represented as strings of zeros and ones. The document also covers wireless LAN protocols like 802.11a, 802.11b, and 802.11g and security protocols like WEP and WPA. It provides examples of wireless technologies in use such as mobile phones, WiFi, and infrared communications.
The document discusses quality of service (QoS) concepts in computer networking. It begins by defining QoS and explaining the need to classify different types of network application traffic, such as voice, video, and data. It then covers various QoS techniques including traffic characterization, queuing algorithms like weighted fair queuing and low latency queuing, and QoS models like integrated services and differentiated services. The document is intended to provide an overview of key QoS concepts for computer networking students.
Watch the full OnDemand Webcast: http://bit.ly/tuneupnetwork
It’s time to make good on that new year’s resolution. Admit it, in a moment of weakness as the clock hit midnight you resolved to dig in and tune up your corporate network in the new year. Well, the new year is already passing quickly by, so if you haven’t yet made good on that resolution, here is your chance. In these slides from our web seminar, we return to the basics – overall network evaluation, baseline measurements and comparisons, typical yet troublesome network issues, sharing bandwidth in the presence of time-sensitive applications, security, and overall network monitoring and reporting, just to name a few. We focus on practical issues and practical methods for improving the overall health of your network.
In these slides, we will cover:
- Critical elements to consider when evaluating your network
- Common pitfalls and how to avoid them
- Developing and using network baselines
- Optimizing network usage in the presence of competing applications and protocols
- Monitoring and reporting on your well-tuned network
What you will learn:
1. How and where to find the data you need
2. How to automate network monitoring and analysis to ensure the success of your tune up
3. How to quickly diagnose problems when things go wrong
Boost your internet experience with the ultimate WiFi Speed Test tool. Discover the true potential of your connection by measuring its speed, reliability, and performance effortlessly. Whether you're a casual user, a gamer, or a professional, this SEO-friendly WiFi Speed Test provides accurate results in seconds. Identify bottlenecks, optimize your network settings, and ensure seamless browsing, streaming, and downloading. Stay ahead of the curve and elevate your online activities with this reliable and efficient WiFi Speed Test.
Simplified Networking and Troubleshooting for K-12 Teacherswebhostingguy
The document provides an overview of networking concepts and troubleshooting tips for K-12 teachers. It discusses common network topologies including star and backbone networks. It also describes network components like hubs, switches, routers and servers. Basic networking concepts such as the OSI model, TCP/IP, IP addressing, subnets, and DNS are explained. Finally, the document provides steps to troubleshoot common issues like no internet access, email problems, printing issues, and joining a domain.
This document discusses quality of service (QoS) requirements for voice over IP (VoIP) and how QoS can be implemented in packet switched networks to address issues like jitter, latency, bandwidth congestion, and packet loss that can negatively impact call quality. It explains that QoS aims to guarantee a certain level of performance for applications like VoIP through techniques like traffic classification, marking, and queuing. The document also provides recommendations for applying QoS on the network edge, core, and internet exchange points to help improve end-to-end call quality.
TECHNICAL WHITE PAPER: NetBackup Appliances WAN OptimizationSymantec
In a world of ever increasing data flow as well as globalization of data centers the effectiveness and utilization of the networks connecting sites is of the highest importance to end users. Even with network enhancement and improvement, the ability of the infrastructure to keep pace with the flow of data has proved not to be in lockstep. To optimize the flow of data verses increasing the pipe that is flows along is seen as critical to keeping operations running and costs minimal. This paper discusses the new WAN Optimization technology that has been introduced in the NetBackup 5220 and 5020 appliances.
This document outlines the WAN Optimization feature enhancements introduced on the NetBackup 5220 and NetBackup 5020 and applies to:
• NetBackup 5220 & 5230 appliances with version N2.5 and above installed
• NetBackup 5020 & 5030 appliances with version D1.4.2 and above installed
Factors which affect the speed of internet computer studies lessonMukalele Rogers
There are several factors that can affect the speed of an Internet connection, including computer processor speed, distance data must travel, network traffic levels, malware/viruses, modem speed, natural conditions, positioning of modems and routers, hardware and software problems, available memory, computer settings, technical issues, and cookies. Addressing these common factors can help optimize connection speed.
Introduction to computer networks ppt downloadzanetorserwaah
This presentation provides an introduction to computer networks. It discusses the definition of a computer network and reasons for networking computers, including sharing information, hardware, software, and centralized administration. It covers different types of networks based on transmission media, size, management method, and topology. Specific topics covered include LANs and WANs, peer-to-peer and client/server networks, common network topologies, transmission media, protocols, network operating systems, and a brief history of the Internet.
This document contains details about the computer networks course subject code EC8551, including:
- Requirements to build a computer network such as computers, network interfaces, switches, hubs, routers, and cables.
- Metrics that influence network performance such as bandwidth, throughput, latency, data loss, and errors.
- Key concepts like bandwidth, latency, error detection, error correction, framing, flow control, and more.
- Differences between circuit switched and packet switched networks.
- Services provided by the data link layer such as framing, reliable delivery, and error detection.
- Parameters used to measure network performance including bandwidth, throughput, latency, and error rate.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024
IR-Optimising-Your-Network.pdf
1. Unified communications and collaboration (UCC) is
changing the world and the way we work. The worldwide
implementation of VoIP and video as major communication
solutions is making these changes possible.
But all new technologies come with challenges and one of
the major hurdles that IT teams face is network performance.
When network performance is compromised, smooth
communication becomes problematic and end users have a
poor experience.
This comprehensive guide will explain everything you need to
know about three common problems experienced as a result
of poor network performance: jitter, latency and packet loss.
We’ll take an in-depth look at these issues, the reasons
you experience them and how to address these issues by
optimizing your network.
A complete guide to
understanding jitter,
latency and packet loss
Optimizing
your network
2. What is packet loss?
What causes packet loss?
Network congestion
Network hardware problems
Software bugs
Overtaxed devices
Wifi packet loss vs wireless packet loss
Security threats
Deficient infrastructure
Ping and packet loss
Upload speed
Download speed
Ping
The effects of packet loss
Diagnosing and fixing packet loss
Example 1
Example 2
Do a ping test
Deep packet inspection
Traceroute packet loss and high latency
Monitoring packet loss
Packet loss
3. In any network environment, data is sent and received
across the network in small units
called packets.
This applies to everything you do on the internet, from emailing, uploading or downloading
images or files, browsing, streaming, gaming – to voice and video communication.
According to a 2017 survey from Statista, in 2017, 24% of surveyed companies claimed
that downtimes cost them between $301,000 and $400,000. In most cases, these
situations of downtimes might have arisen from a seemingly simple issue that escalated
into significant setbacks.
When one or more of these packets is interrupted in its journey, this is known as packet loss.
The Transmission Control Protocol (TCP) divides the file into efficiently sized packets for routing.
Each packet is separately numbered and includes the destination’s internet address.
Each individual packet may travel a different route, and when they have arrived, they are
restored to the original file by the TCP at the receiving end.
What is
packet loss?
4. What causes packet loss?
Network congestion
The primary cause of network packet loss is congestion.
All networks have space limitations, so in simple terms,
network congestion is very much the same as peak
hour traffic.
Think of the queues on the road at certain times of the
day, like early mornings and the end of the working
day. Too much traffic crowding onto the same road can
become bottlenecked when it tries to merge, and the
result is that it doesn’t reach its destination on time.
At peak times, when network traffic hits its maximum
limit, packets are discarded and must wait to be
delivered. Fortunately, most software is designed to
either automatically retrieve and resend those discarded
packets or slow down transfer speed.
Network hardware problems
The speed with which hardware becomes outdated or
redundant these days is another major problem for your
network. Hardware such as firewalls, routers, and network
switches consume a lot of power, and can considerably
weaken network signals. Sometimes organizations
overlook the need to update hardware during expansions
or mergers and this can contribute to packet loss or
connectivity outages.
Software bugs
Closely related to faulty hardware is a buggy software
running on the network device. Bugs or glitches in your
system can sometimes be responsible for disrupting
network performance and preventing the delivery of
packets. Hardware reboots and patches may fix bugs.
Overtaxed devices
When a network is operating at a higher capacity than it
was designed to handle, it weakens and becomes unable
to process packets, and drops them. Most devices have
built-in buffers to assign packets to holding patterns until
they can be sent.
Wired packet loss vs wireless packet loss
As a rule, wireless networks experience more issues
with packet loss than wired networks. Radio frequency
interference, weaker signals, distance and physical
barriers like walls can all cause wireless networks to
drop packets.
With wired networks, faulty cables can be the culprit,
impeding signal flow through the cable.
Security threats
If you’re noticing unusually high rates of packet drop, the
problem could be a security breach. Cybercriminals
hack into your router and instruct it to drop packets.
Another way that hackers can cause packet loss is to
execute a denial-of-service attack (DoS), preventing
legitimate users from accessing files, emails, or online
accounts by flooding the network with too much traffic
to handle. Packet loss can be difficult to fix during a
full-blown security.
Deficient infrastructure
This highlights the importance of a comprehensive
network monitoring solution. Some out-of-packet
monitoring tools were not engineered for the job they’ve
been assigned to do and have limited functionality.
The only way to effectively deal with packet loss
issues is to deploy a seamless network monitoring
and troubleshooting platform that can view your
entire system from a single window. In a nutshell,
comprehensive network monitoring solution =
packet loss fix.
5. Ping and packet loss
The effects of packet loss
When it comes to the determining what constitutes
a strong internet connection, and the reduction of
random packet loss, there are three factors to consider:
upload speed, download speed and ping.
Upload speed
This is how fast you can send data to others. Uploading
is used when sending large files through email, or
in using video to chat with others. Upload speed is
measured in megabits per second (Mbps).
Download speed
This is how fast you can pull data from the server to
you. By default, connections are designed to download
more quickly than they upload. Download speed is also
measured in Mbps.
Ping
This is the reaction time of your connection, or how
quickly you get a response after sending out a request.
A fast ping means a more responsive connection, and
this is especially important in real-time applications like
gaming, and voice and video calls. Ping is measured in
milliseconds (ms).
Anything below a ping of 20 ms is considered ideal,
while anything over 150 ms would result in noticeable
lag.
Even though your ping is good you may still be having
issues with packet loss. Although the data is being
sent and ultimately received quickly by the destination
server, some data might not be getting there correctly.
For users, packet loss can be more than annoying,
particularly in real-time processes like VoIP and video
conferencing. According to a QoS tutorial by Cisco,
packet loss on VoIP traffic should be kept below 1% and
between 0.05% and 5% depending on the type
of video.
Different applications are affected by packet loss in
different ways. For example, when downloading data
files, a 10% packet loss might add only one second to a
ten second download. If packet loss rate is higher,
or there is high latency, it can cause delays to be worse.
Real-time applications like voice and video will be
affected more severely by packet loss. Something as
small as a 2% packet loss is usually quite noticeable to a
listener or viewer, and can cause the conversation to be
stilted and unintelligible.
The effects of packet loss also differs depending on the
application/protocol (TCP/UDP). If a packet is dropped,
or not acknowledged, TCP protocol is designed to
retransmit it. UDP, however, doesn’t have the capability
to retransmit, and therefore doesn’t handle packet loss
as well.
6. Diagnosing and fixing packet loss
Everyone has experienced packet loss in voice calls.
This is where comprehensive network monitoring and
troubleshooting comes into its own. Network monitoring
can quickly and accurately diagnose and identify the
root causes of packet loss problems such as in the
following examples.
Example 1:
During a Teams call, the quality deteriorates and
becomes distorted and patchy, or eventually drops
out completely. But even though Teams may be
having issues, you might still be able to successfully
communicate using Cisco Webex, Google Hangouts or
WhatsApp. This is because of the difference in the way
that each specific program transmits over the internet,
and the route that the packets take.
Example 2:
You may be on a call with a perfect connection to a
server in Springfield, IL but then find you’re experiencing
an exceptionally high packet loss when connecting to
a server in Richmond, VA. This would indicate problems
with the pipeline between your location and the server in
Richmond.
Do a ping test
A ping test is a diagnostic tool that provides data on
how well an internet-enabled device communicates with
another endpoint. A ping test can assess network delays
or issues by sending an Internet Control Message Protocol
(ICMP) packet – or ping – to a specific destination.
ICMP packets contain only a tiny amount of information,
so they don’t use much bandwidth. When the ping
reaches the device, that device recognizes and replies to
the originating device. The total time taken for the ping
to arrive and return is recorded as ‘ping time’ or ‘round
trip time’.
If the number of packets sent and received are not
equal, this means some packets never arrived to or from
your phone. This inevitably leads to call quality issues like
choppy voices, extended silences, jumbled audio and
other call quality problems.
7. Monitoring packet loss
Deep packet inspection
Any organization with a private network will have
hundreds or even thousands of unique connections
and data transfers every day.
Deep Packet Inspection (DPI) is an in-depth way
of examining and managing network traffic. DPI
is one of the most important tasks that network
administrators need to carry out. It locates,
identifies, blocks or re-routes packets with specific
data or code. It examines the contents of packets
passing through a given point and determines what
the packet contains. Most network packets are split
into three parts:
Header – containing instructions about the
data carried by the packet such as length,
synchronization, packet number, protocol as well as
originating and destination addresses.
Payload – the actual data contents, or body of the
packet.
Trailer – also referred to as the footer tells the
receiving device that it has reached the end of the
packet.
Traceroute packet loss and high latency
Traceroute is a command-line tool that comes
with Windows and other operating systems. Along
with the ping command, it’s an important tool for
understanding Internet connection problems.
If you’re having trouble connecting to a website,
traceroute can tell you where the problem is. It can
also help visualize the path traffic takes between
your computer and a web server.
Every network experiences some degree of packet loss,
but what is acceptable? The most important thing to
remember is that prevention is better than cure when
implementing packet loss solutions.
Network monitoring should be the first strategy you use
to preserve and uphold the integrity of your network
environment. Regularly scanning your devices will ensure
that your routers are capable of handling capacity, and
your system is equipped to prevent data loss.
8. What is network latency?
Causes of network latency
Distance
Website construction
End-user issues
Physical issues
Latency vs bandwidth vs throughput
Other types of latency
Fiber optic latency
VoIP latency
Reasons behind VoIP latency and
how to address them
Best practices for monitoring and improving
network latency
How to check network latency
How to measure network latency
How to reduce network latency
How to troubleshoot network latency issues
How to test network latency
What tools help improve network latency?
Latency
9. Network latency, sometimes called lag, is the term
used to describe delays in communication over a
network. In networking, latency is best thought of
as the amount of time it takes for a packet of data
to be captured, transmitted, processed through
multiple devices, then received at its destination
and decoded.
When delays in transmission are small, it’s referred to as a low-latency network
(desirable) and longer delays are called a high-latency network (not so desirable).
Long delays that occur in high-latency networks create bottlenecks in communication.
In the worst cases, it’s like traffic on a four-lane highway trying to merge into a single
lane. High latency decreases communication bandwidth, and can be temporary or
permanent, depending on the source of the delays.
Latency is measured in milliseconds, or during speed tests, it’s referred to as a ping rate.
Obviously, zero to low latency in communication is what we all want. However, standard
latency for a network is explained slightly differently in various contexts, and latency
issues also vary from one network to another.
What is
networklatency?
10. Causes of network latency
Distance
One of the main causes of network latency is distance, or
how far away the device making requests is located from
the servers responding to those requests.
For example, network latency between cities: if a website
is hosted in a data center in Trenton, New Jersey, it will
respond faster to requests from users in Farmingdale,
New York (100 miles away), or most likely within 10-
15 milliseconds. On the other hand, users in Denver,
Colorado (about 1,800 miles away) will face longer
delays of up to 50 milliseconds.
The amount of time it takes for a request to reach a
client device is referred to as Round Trip Time (RTT).
While an increase of a few milliseconds might seem
negligible, there are other considerations that can
increase latency, such as:
•
The to-and-fro communication necessary
for the client and server to make that connection
in the first place.
• The total size and load time of the page.
•
Problems with network hardware which the data
passes through along the way.
Data travelling back and forth across the internet often
has to cross multiple Internet Exchange Points (IXPs),
where routers process and route the data packets, often
having to break them up into smaller packets. All this
additional activity adds a few milliseconds to RTT.
Website construction
The way webpages are constructed makes a difference
to latency. Webpages that carry heavy content, large
images, or load content from several third- party
websites may perform more slowly, as browsers need to
download larger files to display them.
End-user issues
Network problems might appear to be responsible for
latency, but sometimes RTT latency is the result of the
end-user device being low on memory or CPU cycles to
respond in a reasonable timeframe.
Physical issues
In a physical context, common network latency causes
are the components that move data from one point to
the next like physical cabling such as routers, switches
and WiFi access points. In addition, latency can be
influenced by other network devices like application
load balancers, security devices, firewalls and Intrusion
Prevention Systems (IPS).
11. Other types of latency
Reasons behind VoIP latency
and how to address them:
The following describes two other examples of the
effects of latency.
Fiber optic latency
In the case of fiber optic networks, latency refers to the
time delay that affects light as it travels through the
fiber optic network. Latency increases over the distance
traveled, so this must also be factored in to compute
the latency for any fiber optic route.
Based on the speed of light (299,792,458 meters/
second), there is a latency of 3.33 microseconds
(0.000001 of a second) for every kilometer covered.
Light travels slower in a cable which means the latency
of light traveling in a fibre optic cable is around
4.9 microseconds per kilometer.
The quality of fiber optic cable is an important factor in
reducing latency in a network.
VoIP latency
The reasons behind audio latency are based on the
speed of sound. Latency in VoIP is the difference in time
between when a voice packet is transmitted and the
moment it reaches its destination. A latency of 20 ms is
normal for VoIP calls; a latency of up to 150 ms is barely
noticeable and therefore acceptable. Any higher than
that, however, and quality starts to diminish. At 300 ms
or higher, it becomes completely unacceptable.
High latency in VoIP can severely affect call quality,
resulting in:
• Slow and interrupted phone conversations.
•
Overlapping noises, with one speaker interrupting
the other.
• Echo.
•
Disturbed synchronization between voice and other
data types, especially during video conferencing.
Insufficient bandwidth – with a slow internet connection,
insufficient bandwidth means that data packets take
more time reach their destination, and often arrive in the
wrong order.
Firewall blocking traffic – to prevent bottlenecks, always
allow clearance for your VoIP applications within your
firewall software.
Wrong codecs – codecs encode voice signals into digital
data ready to be transmitted. This is often an issue that
your provider needs to solve, however some VoIP apps
allow you to tweak codecs.
Outdated hardware – sometimes the mix of old
hardware and new software can cause latency problems.
Changing your telephone adaptor or other VoIP-specific
software can help. Even your headset can cause latency.
Signal conversion – if your system is converting your
signal to or from analog and digital, this could cause
latency.
12. Best practices for monitoring
and improving network latency
The slowing of your network can be extremely
problematic in the business world, where time is such
a precious commodity. As your network grows bigger,
having additional connections means more points where
delays and issues can happen.
Problems can increase again as more and more
organizations connect to cloud servers, use more
applications and expand to accommodate remote
workers extra branch offices.
Everyone has experienced latency in various aspects of
daily business, and it can severely threaten deadlines,
expected outcomes and eventually ROI. This is where
comprehensive network monitoring and troubleshooting
comes into its own. Network monitoring and
troubleshooting can quickly and accurately diagnose
and identify the root causes of latency and put solutions
in place to reduce impact and improve the problem.
Before you can do anything to improve your network
latency, you need to know how to calculate and measure
it. By becoming familiar with your latency, you’re far
better equipped to troubleshoot.
How to check network latency
If you feel that your network is running slow, you can
check your latency manually by using Windows.
Open a command prompt and type tracert followed by
the destination you’d like to query, such as
cloud.google.com.
How to measure network latency
Network monitoring and management tools will get
this information automatically, but here’s how to do
it manually. Once you type in the tracert command,
you’ll see a list of all routers on the path to that website
address, followed by a time measurement in milliseconds
(ms). Add up all the measurements, and the resulting
quantity is the latency between your machine and the
website in question.
Latency can either be measured as the Round Trip Time
(RTT) or the Time to First Byte (TTFB):
•
RTT - the amount of time it takes a packet to get from
the client to the server and back.
•
TTFB - the amount of time it takes for the server to
receive the first byte of data when the client sends a
request.
13. What tools help improve network latency?
Network monitoring and troubleshooting tools are the
best way to keep tabs on latency, as well as the other
most troubling network problems, packet loss and jitter.
You can typically set network standard expectations
for latency and create alerts when the network latency
reaches a certain threshold above this baseline.
Network monitoring tools can help you set up data
comparisons between different metrics. This can help
you identify performance issues, such as application
performance or errors also affecting network latency.
A network mapping tool can also help you pinpoint
where within the network the performance issues are
occurring, which allows you to troubleshoot problems
more quickly.
Specific traceroute tools monitor packets and how
they move across an IP network, including how many
“hops” the packet took, the roundtrip time, best time (in
milliseconds), as well as the IP addresses and countries
the packet traveled through.
By improving your network speed and reducing latency,
your business processes will also make leaps and bounds
towards efficiency and high performance.
How to reduce network latency
One simple way to improve network latency is to check
that others on your network aren’t unnecessarily
using up your bandwidth, or increasing your latency
with excessive downloads or streaming. Then, check
application performance to determine whether
applications are acting unexpectedly and potentially
placing pressure on the network.
Subnetting is another way to help reduce latency across
your network, by grouping together endpoints that
communicate most frequently with each other.
Additionally, you could use traffic shaping and
bandwidth allocation to improve latency for the
business-critical parts of your network.
Finally, you can use a load balancer to help offload traffic
to parts of the network with the capacity to handle some
additional activity.
How to troubleshoot network latency issues
Manually troubleshooting issues across a large network can
become complex, which highlights again the importance of
network monitoring and troubleshooting tools.
To check if any of the devices on your network are
specifically causing issues, you can try disconnecting
computers or network devices and restarting all the
hardware. You’ll need to ensure that you have network
monitoring deployed.
If you still have latency problems after checking all your
local devices, it’s the issues could be coming from the
destination you’re trying to connect to.
How to test network latency
Testing network latency can be done by using ping or
traceroute (tracert), although, comprehensive network
monitoring and performance managers can test and
check latency more accurately.
Maintaining a reliable network is an important part of
a smoothly operating business. Network issues can
become worse if they’re not managed properly.
14. What is network jitter?
The technology behind jitter
Data packets
Header
Payload
Trailer
VoIP
Examples of jitter
Constant jitter
Transient jitter
Short term delay variation
The effects of jitter
What is acceptable network jitter?
What can cause network jitter?
Network congestion
Poor hardware performance
Wireless jitter
Not implementing packet prioritization
Quality of Service (QoS) and jitter
QoS tools to address jitter
Queuing
Link fragmentation and interleaving (LFI)
Compression
Traffic shaping
How is jitter measured?
Single endpoint
Double endpoint
Bandwidth testing
How to fix network jitter issues
Jitter buffering
Perform a bandwidth test
Improvements from within
- Upgrade your ethernet cable
- Check your device frequency
-
Reduce unnecessary bandwidth
usage during work hours
- Schedule updates outside of business hours
Jitter
15. Technically, jitter is a variance in latency,
or the time delay between when a signal
is transmitted and when it is received. This
variance is measured in milliseconds (ms)
and is described as the disruption in the
normal sequence of sending data packets.
What is
network jitter?
16. The technology
behind jitter
Data packets
To define jitter in networking, it comes down to packets.
Packet jitter definition means that all data, in fact
everything you do on the internet, involves packets. All
text, images, audio or video is transmitted in packets
over a given network path. When you send or receive
an email, search for information on web pages, stream,
game or shop online, digital information is despatched,
received, ‘unscrambled’ and ‘reassembled’ ready to
view and listen to. Packet switched networks allow the
exchange of all this information.
Most network packets are split into three parts:
Header
The header contains instructions about the data carried
by packet such as:
Packet length - some networks have fixed-length
packets, while others rely on the header to contain
this information.
Synchronization - to help the packet align with
the network.
Packet number - identifying which packet in
the sequence.
Protocol - defines what type of packet is being
transmitted whether it’s e-mail, web page,
streaming video.
Destination address - where the packet is going.
Originating address - where the packet came from.
Payload
This is the actual data or body that is being delivering
to the destination. If a packet is fixed-length, then the
payload may be topped up with blank information to
make it the right size.
Trailer
The trailer, sometimes called the footer, tells the
receiving device that it has reached the end of the
packet. It may also have some type of error checking.
The most common error checking used in packets is
Cyclic Redundancy Check (CRC).
Jitter VoIP
VoIP technology converts fragments of your voice into
data packets which are transmitted digitally via the
internet. One of the most common causes of jitter on
VoIP services is the absence of packet prioritization. If
voice packets aren’t prioritized, then the end user is very
likely to experience jitter.
A massive amount of information is constantly being
transmitted back and forth - millions of packets every
second - and all this data takes a toll on network
resources, often resulting in delay. The delay may not be
as apparent when downloading a file or an email, but
when your voice arrives in disorganized packets, it will
sound distorted and out of sequence.
17. Examples of jitter
What is acceptable
network jitter?
The effects of jitter
Constant jitter
This is a roughly constant level of packet to packet delay
variation.
Transient jitter
Characterized by a substantial gradual delay that may
be incurred by a single packet.
Short term delay variation
An increase in delay that persists for some number of
packets and may be accompanied by an increase in
packet to packet delay variation. This type of jitter is
usually due to congestion and route changes.
Some applications and services have a higher level of
tolerance for jitter than others. So what is acceptable
network jitter?
For example, jitter doesn’t affect sending emails as much
as it would a voice chat. So, it depends on what we’re
willing to accept as irregularities and fluctuations in data
transfers. But poor audio and video quality leads to a
poor user experience and can impact an organization’s
bottom line.
All networks experience some amount of latency,
especially wide area networks. Ideally, over a normally
functioning network, packets travel in equal intervals,
with a 10ms delay between packets. With high jitter, this
could increase to 50ms, severely disrupting the intervals
and making it difficult for the receiving computer to
process the data.
Ideally, jitter should be below 30ms. Packet loss should be
no more than 1%, and network latency shouldn’t exceed
150 ms one-way (300 ms return).
Packet jitter can cause flickering display monitors,
delayed data transmission and poor processor
performance.
IP jitter in VoIP communication can severely impact
the call quality of telephony and video conferencing,
even causing conversations to ‘drop out’, and become
jumbled and difficult to understand.
As a result, high jitter is a big problem for real-time
applications like digital voice and video communication,
as well as streaming and online gaming.
18. What can cause network jitter?
Quality of Service
(QoS) and jitter
QoS tools to
address jitter
Managing network jitter comes down to understanding
what causes jitter in computer networks. Doing a
regular network jitter test can reduce the prevalence of
jitter within your network.
Network congestion
Insufficient bandwidth is a common problem. Networks
become overcrowded with traffic congestion when too
many active devices are consuming bandwidth.
Poor hardware performance
Older networks with outdated equipment including
routers, cables or switches could be the causes of jitter.
Wireless jitter
One of the downsides of using a wireless network is a
lower-quality network connection. Wired connections
will help to ensure that voice and video call systems
deliver a higher quality user experience.
Not implementing packet prioritization
For VoIP systems in particular, jitter occurs when audio
data is not prioritized to be delivered before other types
of traffic.
QoS is the technology that manages data traffic in
order to reduce jitter on your network and prevent or
reduce the degradation of quality. QoS controls and
manages network resources by setting priorities by
which data is sent on the network.
There are tools and techniques which are often
included in an organization’s network Service Level
Agreement (SLA) to guarantee an acceptable level of
performance.
Queuing
Enables you to prioritize or order packets so that delay-
sensitive packets leave their queues more quickly than
delay-insensitive packets.
Link fragmentation and interleaving (LFI)
Routers do not pre-empt a packet that is currently
being transmitted, so LFI reduces the sizes of larger
packets into smaller fragments before sending them.
Compression
Payload or headers can be compressed, and this
reduces the overall number of bits required to transmit
the data. This requires less bandwidth, meaning queues
shrink, which in turn reduces delay.
Traffic shaping
Artificially increases delay to reduce drops inside a
Frame Relay or ATM network.
19. How is jitter
measured?
How to fix network
jitter issues
Single endpoint
Where your network has control over just one
of the endpoints (aka single-ended), jitter is
determined by measuring the mean round-trip
time (RTT), and the minimum RTT of a series of
voice packets.
Double endpoint
In a double-ended path, the measurement
used is the instantaneous jitter, or the variation
between the intervals for transmitting and
receiving a single packet. Jitter is the average
difference between instantaneously measured
jitter and the average instantaneous jitter
throughout the transmission of a series of data
packets.
Bandwidth testing
Performing a bandwidth test can also determine
the level of jitter. A bandwidth test assesses your
internet connection’s upload and download
speeds, jitter times and your network’s overall
capacity.
Troubleshooting network jitter can be tricky because of
its unpredictability. Keeping jitter to a minimum begins
by ensuring that your network is initially properly set
up. Ensuring a quality network connection, enough
bandwidth, and predictable latency can help reduce
network jitter.
Jitter buffering
VoIP endpoints such as desk phones and ATAs usually
include a jitter buffer to intentionally delay incoming
data packets. A jitter buffer ensures that the receiving
device can store a set number of packets and then
realign them into the proper order, so that the receiver
experiences minimum sound distortion.
Jitter buffers are one way to address network jitter
and latency but will not always work. If a jitter buffer
is too small then too many packets may be discarded,
meaning bad call quality. If a jitter buffer is too large,
then the additional delay can lead to conversational
difficulty.
A typical jitter buffer configuration is 30ms to 50ms in
size. You can increase buffer size to a point, but usually
they are only effective for delay variations of less than
100 ms.
Perform a bandwidth test
Bandwidth testing sends files over a network to a specific
computer, then measures the time required for the
files to download at the destination. This determines
a theoretical data speed between the two points,
measured in kilobits per second (Kbps) or megabits per
second (Mbps).
Bandwidth tests can vary greatly. Factors that affect
testing can be internet traffic, noise on data lines, file
sizes, and load demand on the server at the time of
testing. Bandwidth testing should ideally be carried out
several times to determine an average throughput.
Improvements from within
Solving your VoIP network jitter problems may not be as
challenging as you think.
Upgrade your ethernet cable - Outdated cables
and switches can often cause high jitter issues.
The latest cables are capable of transmitting data at
250 MHz, as opposed to 125MHz, potentially solving
ethernet jitter.
Check your device frequency - A VoIP phone that
operates at a higher frequency than a standard
2.4 GHz could cause interference on your network.
Some phones run at frequencies as high as 5.8GHz,
which could potentially exacerbate jitter across your
network.
Reduce unnecessary bandwidth usage during
work hours - Using large amounts of bandwidth for
activities not related to work, like network gaming, or
streaming video content, can make jitter worse.
Schedule updates outside of business hours –
Updating applications and operating systems should
be carried out outside work times to free up capacity
for more essential communications.
20. Summary
Delivering a great user experience across your UC environment
is no small task. Network jitter, packet loss and latency, are major
obstacles standing in the way of clear communication and can
universally affect your user experience.
But with careful planning and the right technology partners you
can easily manage these challenges and optimize your network to
enhance the UC experience for your colleagues and customers.