A Statistical Approach to Adaptive Playout Scheduling in Voice Over Internet ...IJECEIAES
This document summarizes a proposed statistical approach to adaptive playout scheduling in Voice over Internet Protocol (VoIP) communication. The approach estimates the optimal buffer delay for each packet based on network statistics, packet loss rate, and buffer availability. It uses a window-based method to track recent network conditions and estimate delay for the current packet. Buffer delay is calculated based on estimated jitter, a delay factor accounting for surrounding packet arrival, and late packet loss rate. Experimental results show this approach allocates buffer delay with the lowest late packet loss rate compared to other algorithms.
ROUTING PROTOCOLS FOR DELAY TOLERANT NETWORKS: SURVEY AND PERFORMANCE EVALUATIONijwmn
Delay Tolerant Networking (DTN) is a promising technology that aims to provide efficient communication
between devices in a network with no guaranteed continuous connectivity. Most existing routing schemes
for DTNs exploit the advantage of message replication to achieve high message delivery rate. However,
these schemes commonly suffer from large communication overhead due to the lack of efficient mechanisms
to control message replication. In this paper we give a brief survey on routing protocols designed for
DTNs, and evaluate the performance of several representative routing protocols including Epidemic, Spray
and Wait, PRoPHET, and 3R through extensive trace-driven simulations. Another objective of this work is
to evaluate the security strength of different routing schemes under common DTN attacks such as the black
hole attack. The results and analysis presented in this paper can provide useful guidance on the design and
selection of routing protocols for given delay-tolerant applications.
A MECHANISM FOR EARLY DETECTING DDOS ATTACKS BASED ON M/G/R PS QUEUEIJNSA Journal
When service system is under DDoS attacks, it is important to detect anomaly signature at starting time of attack for timely applying prevention solutions. However, early DDoS detection is difficult task because the velocity of DDoS attacks is very high. This paper proposes a DDoS attack detection method by modeling service system as M/G/R PS queue and calculating monitoring parameters based on the model in odder to
early detect symptom of DDoS attacks. The proposed method is validated by experimental system and it gives good results.
Packet Loss Distributions of TCP using Web100Zoriel Salado
This research studied the time distribution between packet loss events in TCP connections using a testbed with varying bandwidths and packet loss rates. The results show that for ADSL and T1 connections, over 80% of congestion events occurred within 1 second or less. For an OC-1 connection, over 80% of events were within 0.25 seconds. The time between events was shorter for higher bandwidth links. To maximize bandwidth utilization, TCP would need a bandwidth estimation mechanism performing updates within 1 second for highly congested links.
(Slides) P2P video broadcast based on per-peer transcoding and its evaluatio...Naoki Shibata
Shibata, N., Yasumoto, K., and Mori, M.: P2P Video Broadcast based on Per-Peer Transcoding and its Evaluation on PlanetLab, Proc. of 19th IASTED Int'l. Conf. on Parallel and Distributed Computing and Systems (PDCS2007), (November 2007).
http://ito-lab.naist.jp/themes/pdffiles/071121.shibata.pdcs2007.pdf
- The document discusses implementing a system to stream live data from simulation software to a streaming server in real-time to improve engineering education through remote collaborative experiments. It explores using hooking/function injection, TCP/IP sniffing, and an input plugin for a streaming producer but finds each method challenging to implement due to limitations of the simulation programs, operating system, or dependencies. The goal of real-time streaming of both the software and experiments has proven difficult to achieve.
IRJET- Secure Data Transmission from Malicious Attacks: A ReviewIRJET Journal
This document summarizes various techniques that have been proposed for secure data transmission in mobile ad hoc networks in the face of security attacks. It discusses works that use techniques like self-protocol trustiness and the Dempster-Shafer theory to detect blackhole attacks. A dynamic forwarding window technique is described for detecting denial of service attacks in wireless sensor networks. The document also reviews improved CONFIDANT and other techniques for detecting grayhole, sinkhole, and jellyfish attacks on AODV routing. Cryptographic techniques including elliptic curve cryptography have also been proposed and evaluated for secure transmission and misbehavior detection in MANETs.
A Statistical Approach to Adaptive Playout Scheduling in Voice Over Internet ...IJECEIAES
This document summarizes a proposed statistical approach to adaptive playout scheduling in Voice over Internet Protocol (VoIP) communication. The approach estimates the optimal buffer delay for each packet based on network statistics, packet loss rate, and buffer availability. It uses a window-based method to track recent network conditions and estimate delay for the current packet. Buffer delay is calculated based on estimated jitter, a delay factor accounting for surrounding packet arrival, and late packet loss rate. Experimental results show this approach allocates buffer delay with the lowest late packet loss rate compared to other algorithms.
ROUTING PROTOCOLS FOR DELAY TOLERANT NETWORKS: SURVEY AND PERFORMANCE EVALUATIONijwmn
Delay Tolerant Networking (DTN) is a promising technology that aims to provide efficient communication
between devices in a network with no guaranteed continuous connectivity. Most existing routing schemes
for DTNs exploit the advantage of message replication to achieve high message delivery rate. However,
these schemes commonly suffer from large communication overhead due to the lack of efficient mechanisms
to control message replication. In this paper we give a brief survey on routing protocols designed for
DTNs, and evaluate the performance of several representative routing protocols including Epidemic, Spray
and Wait, PRoPHET, and 3R through extensive trace-driven simulations. Another objective of this work is
to evaluate the security strength of different routing schemes under common DTN attacks such as the black
hole attack. The results and analysis presented in this paper can provide useful guidance on the design and
selection of routing protocols for given delay-tolerant applications.
A MECHANISM FOR EARLY DETECTING DDOS ATTACKS BASED ON M/G/R PS QUEUEIJNSA Journal
When service system is under DDoS attacks, it is important to detect anomaly signature at starting time of attack for timely applying prevention solutions. However, early DDoS detection is difficult task because the velocity of DDoS attacks is very high. This paper proposes a DDoS attack detection method by modeling service system as M/G/R PS queue and calculating monitoring parameters based on the model in odder to
early detect symptom of DDoS attacks. The proposed method is validated by experimental system and it gives good results.
Packet Loss Distributions of TCP using Web100Zoriel Salado
This research studied the time distribution between packet loss events in TCP connections using a testbed with varying bandwidths and packet loss rates. The results show that for ADSL and T1 connections, over 80% of congestion events occurred within 1 second or less. For an OC-1 connection, over 80% of events were within 0.25 seconds. The time between events was shorter for higher bandwidth links. To maximize bandwidth utilization, TCP would need a bandwidth estimation mechanism performing updates within 1 second for highly congested links.
(Slides) P2P video broadcast based on per-peer transcoding and its evaluatio...Naoki Shibata
Shibata, N., Yasumoto, K., and Mori, M.: P2P Video Broadcast based on Per-Peer Transcoding and its Evaluation on PlanetLab, Proc. of 19th IASTED Int'l. Conf. on Parallel and Distributed Computing and Systems (PDCS2007), (November 2007).
http://ito-lab.naist.jp/themes/pdffiles/071121.shibata.pdcs2007.pdf
- The document discusses implementing a system to stream live data from simulation software to a streaming server in real-time to improve engineering education through remote collaborative experiments. It explores using hooking/function injection, TCP/IP sniffing, and an input plugin for a streaming producer but finds each method challenging to implement due to limitations of the simulation programs, operating system, or dependencies. The goal of real-time streaming of both the software and experiments has proven difficult to achieve.
IRJET- Secure Data Transmission from Malicious Attacks: A ReviewIRJET Journal
This document summarizes various techniques that have been proposed for secure data transmission in mobile ad hoc networks in the face of security attacks. It discusses works that use techniques like self-protocol trustiness and the Dempster-Shafer theory to detect blackhole attacks. A dynamic forwarding window technique is described for detecting denial of service attacks in wireless sensor networks. The document also reviews improved CONFIDANT and other techniques for detecting grayhole, sinkhole, and jellyfish attacks on AODV routing. Cryptographic techniques including elliptic curve cryptography have also been proposed and evaluated for secure transmission and misbehavior detection in MANETs.
Detecting Misbehavior Nodes Using Secured Delay Tolerant NetworkIRJET Journal
This document proposes a method called Statistical-based Detection of Blackhole and Greyhole attackers (SDBG) to detect misbehaving nodes in delay tolerant networks. SDBG can detect both individual misbehaving nodes as well as nodes that are colluding together. It works by having each node record encounter data with other nodes, including the number of messages sent and received. Individual nodes that drop many messages can be detected based on having a low message forwarding ratio. Colluding nodes can be detected because they will have sent many messages to each other to fake good behavior. The method aims to accurately detect misbehaving nodes while keeping false positives low. Extensive simulations showed it can work well across different network conditions.
Detection of Malicious Circuitry Using Transition Probability Based Node Redu...TELKOMNIKA JOURNAL
In recent years, serious concerns have been raised against the tampering of integrated circuits due to outsourcing of circuits for fabrication. It has led to the addition of malicious circuitry known as Hardware Trojan. In this paper, a transition probability based node reduction technique for faster and efficient Hardware Trojan (HT) detection has been attempted. In the proposed method, the fact that the least controllable and observable nodes or the nodes with least transition probability are more vulnerable as Trojan sites is taken into consideration. The nodes that have lesser activity than the threshold are the candidate nodes. At each candidate node, segmentation is done for further leakage power analysis to detect the presence of Trojans. Experimental results observed on ISCAS’85 and ISCAS’89 benchmark circuits illustrate that the proposed work can achieve remarkable node reduction upto 78.81% and time reduction upto 58.7%. It was also observed that the circuit activity can be increased by varying the input probability. Hence, for further reduction in the Trojan activation time, the weighted input probability was obtained.
This document proposes using a linear prediction model to detect a wide range of flooding distributed denial of service (DDoS) attacks. It models the entropy of incoming network traffic over time using a linear prediction technique commonly applied to financial time series. The model is tested on simulated network data containing normal traffic and introduced attacks of varying rates. Results show the linear prediction model can successfully detect attacks with low rates and delays by identifying anomalies in the modeled entropy time series compared to normal traffic patterns. This approach aims to provide a fast and effective method for detecting different types of flooding DDoS attacks.
Virtual Machine Incorporated Sharing Model for Resource Utilizationidescitation
Cooperation and autonomy of virtual machines are
important features of virtualization where resources are
shared among virtual machines in a resource constrained
cloud environment. To facilitate resource sharing, this paper
proposes a resource sharing facility, called the VM Incorporated
RPC, that coordinates the remote procedure call (RPC) with
virtual machine based memory management. In this paper,
we present a process based resource sharing model in case of
collocated virtual machines. Evaluation of our algorithm
demonstrates that sharing of resources within collocated
virtual machines often results in utilizing almost 90% of the
resource potential when compared to inter machine sharing
which contributes a lesser amount of resource utilization.
Relevance-Based Compression of Cataract Surgery Videos Using Convolutional Ne...Alpen-Adria-Universität
The document proposes a relevance-based compression method for cataract surgery videos using convolutional neural networks. The method uses Mask R-CNN to detect relevant regions like the cornea and instruments. Pixels outside these regions are removed or compressed at lower quality. Testing showed the method achieved up to 68% reduction in video size while maintaining good quality for relevant regions. The summaries provide the key information about the proposed method and results at a high level in 3 sentences or less as requested.
Objective and Subjective QoE Evaluation for Adaptive Point Cloud StreamingAlpen-Adria-Universität
Volumetric media has the potential to provide the six degrees of freedom (6DoF) required by truly immersive media. However, achieving 6DoF requires ultra-high bandwidth transmissions, which real-world wide area networks cannot provide economically. Therefore, recent efforts have started to target the efficient delivery of volumetric media, using a combination of compression and adaptive streaming techniques. It remains, however, unclear how the effects of such techniques on the user-perceived quality can be accurately evaluated. In this paper, we present the results of an extensive objective and subjective quality of experience (QoE) evaluation of volumetric 6DoF streaming. We use PCC-DASH, a standards-compliant means for HTTP adaptive streaming of scenes comprising multiple dynamic point cloud objects. By means of a thorough analysis we investigate the perceived quality impact of the available bandwidth, rate adaptation algorithm, viewport prediction strategy, and user's motion within the scene. We determine which of these aspects has more impact on the user's QoE, and to what extent subjective and objective assessments are aligned.
ComplexCTTP: Complexity Class Based Transcoding Time Prediction for Video Seq...Alpen-Adria-Universität
HTTP Adaptive Streaming of video content is becoming an integral part of the Internet and accounts for the majority of today’s traffic. Although Internet bandwidth is constantly increasing, video compression technology plays an important role and the major challenge is to select and set up multiple video codecs, each with hundreds of transcoding parameters. Additionally, the transcoding speed depends directly on the selected transcoding parameters and the infrastructure used. Predicting transcoding time for multiple transcoding parameters with different codecs and processing units is a challenging task, as it depends on many factors. This paper provides a novel and considerably fast method for transcoding time prediction using video content classification and neural network prediction. Our artificial neural network (ANN) model predicts the transcoding times of video segments for state-of-the-art video codecs based on transcoding parameters and content complexity. We evaluated our method for two video codecs/implementations (AVC/x264 and HEVC/x265) as part of large-scale HTTP Adaptive Streaming services. The ANN model of our method is able to predict the transcoding time by minimizing the mean absolute error (MAE) to 1.37 and 2.67 for x264 and x265 codecs, respectively. For x264, this is an improvement of 22% compared to the state of the art.
DDoS Attack Detection & Mitigation in SDNChao Chen
This document summarizes a presentation on detecting and mitigating distributed denial of service (DDoS) attacks in software-defined networks. It discusses using sFlow and the Floodlight controller to detect common DDoS attack types like ICMP floods, SYN floods, and DNS amplification. An application was developed in Python to classify attacks and push static flow entries to direct attack traffic to the sFlow collector for analysis. The scheme was tested in a Mininet virtual network and shown to successfully mitigate ICMP and SYN flood attacks. Future work includes testing DNS amplification and UDP floods, implementing adaptive sampling rates and thresholds, and designing an unblocking mechanism.
Labmeeting - 20150831 - Overhead and Performance of Low Latency Live Streamin...Syuan Wang
This document summarizes research into reducing latency for live video streaming using MPEG-DASH. It introduces MPEG-DASH and how using HTTP chunked transfer encoding and Gradual Decoding Refresh encoding can help lower latency compared to basic DASH. The paper describes experiments conducted to generate and distribute live content using these techniques and evaluate latency, finding they were able to achieve latency as low as 240ms.
This document is a dissertation submitted by Ameya Vashishth in partial fulfillment of a Bachelor of Technology degree. It discusses denial of service (DoS) attacks and mitigation techniques. The dissertation provides an overview of DoS attacks, describes different types of attacks like Smurf, ping flood, TCP SYN flood and UDP flood. It also discusses distributed DoS attacks and recommended tools to perform DDoS attacks. The document concludes with discussing various countermeasures that can be used to mitigate DoS and DDoS attacks.
MPEG Dynamic Adaptive Streaming over HTTP (DASH) is a new streaming standard that has been recently ratified as an international standard (IS). In comparison to other streaming systems, e.g., HTTP progressive download, DASH is able to handle varying bandwidth conditions providing smooth streaming. Furthermore, it enables NAT and Firewall traversal, flexible and scalable deployment as well as reduced infrastructure costs due to the reuse of existing Internet infrastructure components, e.g., proxies, caches, and Content Distribution Networks (CDN). Recently, the Hypertext Transfer Protocol Bis (httpbis) working group of the IETF has officially started the development of HTTP 2.0. Initially three major proposals have been submitted to the IETF i.e., Googles' SPDY, Microsofts' HTTP Speed+Mobility and Network-Friendly HTTP Upgrade, but SPDY has been chosen as working draft for HTTP 2.0. In this paper we implemented MPEG-DASH over HTTP 2.0 (i.e., SPDY), demonstrating its potential benefits and drawbacks. Moreover, several experimental evaluations have been performed that compare HTTP 2.0 with HTTP 1.1 and HTTP 1.0 in the context of DASH. In particular, the protocol overhead, the performance for different round trip times, and DASH with HTTP 2.0 in a lab test scenario has been evaluated in detail.
This document discusses various approaches for multimedia conferencing including centralized, distributed, and peer-to-peer architectures. It covers key considerations like transport protocols, audio and video quality, security, and floor control. It also discusses using IP multicast versus application-level multicast and different audio mixing and adaptive playout techniques.
The document discusses research on quantifying user satisfaction (QoE) in VoIP applications like Skype calls. It presents three key contributions:
1) Developing the first QoE measurement methodology based on analyzing large-scale Skype call data to correlate call duration with network quality factors like jitter and bit rate.
2) Proposing OneClick, a simple framework for crowdsourced QoE experiments based on user clicks to indicate dissatisfaction.
3) Introducing the first crowdsourcable QoE evaluation methodology to verify user judgments.
Scalable Service Oriented Architecture for Audio/Video ...Videoguy
The document summarizes research on developing a scalable service-oriented architecture for video conferencing using publish/subscribe event brokers to distribute real-time audio and video streams. It outlines the GlobalMMCS architecture, which separates media processing from delivery for scalability. Performance tests showed a single broker could support 1500 audio or 400 video participants, and distributed brokers improved scalability further.
Scalable Service Oriented Architecture for Audio/Video ...Videoguy
The document summarizes research on developing scalable videoconferencing systems using publish/subscribe event brokers to distribute audio and video streams. It proposes a service-oriented architecture with independently scalable components for media distribution, processing, and meeting management. Performance tests show a single broker can support up to 1500 users for audio-only conferences and 400 users for video conferences.
This document provides an overview and summary of a lecture on real-time communication over computer networks:
1. The lecture covered techniques for real-time multimedia communication implemented at the transport and application layers, including buffering to remedy jitter, forward error correction to recover lost packets, and interleaving to reduce the effects of packet loss bursts.
2. Key protocols discussed include RTP/RTCP for real-time media transport, RTSP for streaming media applications, and H.323 for videoconferencing.
3. Challenges for real-time multimedia over best-effort IP networks are meeting delay constraints for interactive applications while providing loss tolerance, and supporting large-scale multicast sessions.
This document provides a summary of key topics covered in a lecture on computer networks:
- Circuit switching and packet switching networking models, including their differences in allocating and sharing network resources.
- How the Internet evolved from millions of individual access networks connecting to each other through a hierarchical system of transit providers, internet exchange points, and content delivery networks.
- An overview of network security challenges like malware, denial of service attacks, packet sniffing, and IP spoofing. The importance of considering security in all layers of network design is also discussed.
HTTP/2 for Developers: How It Changes Developer's Life?
by Svetlin Nakov (SoftUni) - http://www.nakov.com
jProfessionals Conference - Sofia, 22-Nov-2015
Key new features in HTTP/2
- Multiplexing: multiple streams over a single connection
- Header compression: reuse headers from previous requests
- Sever push: multiple parallel responses for a single request
- Prioritization and flow control: resources have priorities
TCP Performance analysis Wireless Multihop NetworksAbhishek Kona
This document summarizes an experiment analyzing TCP performance over multi-hop wireless networks using a test bed. The experiment varied hop count, window size, and TCP variants. Results showed degradation in throughput with increased hops. Throughput peaked at certain window sizes depending on hops. WESTWOOD marginally outperformed other variants with small windows. Turning off TCP SACK gave better performance over 3 hops. Limitations included node availability and high data variance. Previous studies are difficult to emulate fully in real deployments.
This document presents research on Stheno, a middleware platform that integrates real-time (RT) and fault tolerance (FT) support in a peer-to-peer (P2P) system. Stheno was motivated by the need to support large-scale critical infrastructure systems with tight timing requirements. The document outlines Stheno's architecture, which leverages techniques such as resource reservation, priority-based threading, and replication to provide both RT and FT guarantees. An evaluation of a Stheno prototype found it can meet sub-second end-to-end latency and failover requirements, even under faults. The research contributes a novel RT+FT+P2P middleware and demonstrates its ability to support systems with mixed criticality
This document discusses implementing media-aware network elements (MANEs) on legacy devices to perform real-time adaptation of scalable video coded (SVC) bitstreams. It proposes using an ordinary WiFi router to intercept and adapt SVC streams in-network using a proxy approach. Evaluations show the router's CPU can support 4 parallel SVC streams with under 30% load and delay under 100ms, showing MANEs are feasible on existing home network devices.
Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adap...SmartenIT
Tobias Hoßfeld, Michael Seufert, Christian Sieber, Thomas Zinner
Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adaptive Streaming.
6th International Workshop on Quality of Multimedia Experience (QoMEX), Singapore, September 2014.
Abstract:
HTTP Adaptive Streaming (HAS) is employed by more and more video streaming services in the Internet. It allows to adapt the downloaded video quality to the current network conditions, and thus, avoids stalling (i.e., playback interruptions) to the greatest possible extend. The adaptation of video streams is done by switching between different quality representation levels, which influences the user perceived quality of the video stream. In this work, the influence of several adaptation parameters, namely, switch amplitude (i.e., quality level difference), switching frequency, and recency effects, on Quality of Experience (QoE) is investigated. Therefore, crowdsourcing experiments were conducted in order to collect subjective ratings for different adaptation-related test conditions. The results of these subjective studies indicate the influence of the adaptation parameters, and based on these findings a simplified QoE model for HAS is presented, which only relies on the switch amplitude and the playback time of each layer.
Detecting Misbehavior Nodes Using Secured Delay Tolerant NetworkIRJET Journal
This document proposes a method called Statistical-based Detection of Blackhole and Greyhole attackers (SDBG) to detect misbehaving nodes in delay tolerant networks. SDBG can detect both individual misbehaving nodes as well as nodes that are colluding together. It works by having each node record encounter data with other nodes, including the number of messages sent and received. Individual nodes that drop many messages can be detected based on having a low message forwarding ratio. Colluding nodes can be detected because they will have sent many messages to each other to fake good behavior. The method aims to accurately detect misbehaving nodes while keeping false positives low. Extensive simulations showed it can work well across different network conditions.
Detection of Malicious Circuitry Using Transition Probability Based Node Redu...TELKOMNIKA JOURNAL
In recent years, serious concerns have been raised against the tampering of integrated circuits due to outsourcing of circuits for fabrication. It has led to the addition of malicious circuitry known as Hardware Trojan. In this paper, a transition probability based node reduction technique for faster and efficient Hardware Trojan (HT) detection has been attempted. In the proposed method, the fact that the least controllable and observable nodes or the nodes with least transition probability are more vulnerable as Trojan sites is taken into consideration. The nodes that have lesser activity than the threshold are the candidate nodes. At each candidate node, segmentation is done for further leakage power analysis to detect the presence of Trojans. Experimental results observed on ISCAS’85 and ISCAS’89 benchmark circuits illustrate that the proposed work can achieve remarkable node reduction upto 78.81% and time reduction upto 58.7%. It was also observed that the circuit activity can be increased by varying the input probability. Hence, for further reduction in the Trojan activation time, the weighted input probability was obtained.
This document proposes using a linear prediction model to detect a wide range of flooding distributed denial of service (DDoS) attacks. It models the entropy of incoming network traffic over time using a linear prediction technique commonly applied to financial time series. The model is tested on simulated network data containing normal traffic and introduced attacks of varying rates. Results show the linear prediction model can successfully detect attacks with low rates and delays by identifying anomalies in the modeled entropy time series compared to normal traffic patterns. This approach aims to provide a fast and effective method for detecting different types of flooding DDoS attacks.
Virtual Machine Incorporated Sharing Model for Resource Utilizationidescitation
Cooperation and autonomy of virtual machines are
important features of virtualization where resources are
shared among virtual machines in a resource constrained
cloud environment. To facilitate resource sharing, this paper
proposes a resource sharing facility, called the VM Incorporated
RPC, that coordinates the remote procedure call (RPC) with
virtual machine based memory management. In this paper,
we present a process based resource sharing model in case of
collocated virtual machines. Evaluation of our algorithm
demonstrates that sharing of resources within collocated
virtual machines often results in utilizing almost 90% of the
resource potential when compared to inter machine sharing
which contributes a lesser amount of resource utilization.
Relevance-Based Compression of Cataract Surgery Videos Using Convolutional Ne...Alpen-Adria-Universität
The document proposes a relevance-based compression method for cataract surgery videos using convolutional neural networks. The method uses Mask R-CNN to detect relevant regions like the cornea and instruments. Pixels outside these regions are removed or compressed at lower quality. Testing showed the method achieved up to 68% reduction in video size while maintaining good quality for relevant regions. The summaries provide the key information about the proposed method and results at a high level in 3 sentences or less as requested.
Objective and Subjective QoE Evaluation for Adaptive Point Cloud StreamingAlpen-Adria-Universität
Volumetric media has the potential to provide the six degrees of freedom (6DoF) required by truly immersive media. However, achieving 6DoF requires ultra-high bandwidth transmissions, which real-world wide area networks cannot provide economically. Therefore, recent efforts have started to target the efficient delivery of volumetric media, using a combination of compression and adaptive streaming techniques. It remains, however, unclear how the effects of such techniques on the user-perceived quality can be accurately evaluated. In this paper, we present the results of an extensive objective and subjective quality of experience (QoE) evaluation of volumetric 6DoF streaming. We use PCC-DASH, a standards-compliant means for HTTP adaptive streaming of scenes comprising multiple dynamic point cloud objects. By means of a thorough analysis we investigate the perceived quality impact of the available bandwidth, rate adaptation algorithm, viewport prediction strategy, and user's motion within the scene. We determine which of these aspects has more impact on the user's QoE, and to what extent subjective and objective assessments are aligned.
ComplexCTTP: Complexity Class Based Transcoding Time Prediction for Video Seq...Alpen-Adria-Universität
HTTP Adaptive Streaming of video content is becoming an integral part of the Internet and accounts for the majority of today’s traffic. Although Internet bandwidth is constantly increasing, video compression technology plays an important role and the major challenge is to select and set up multiple video codecs, each with hundreds of transcoding parameters. Additionally, the transcoding speed depends directly on the selected transcoding parameters and the infrastructure used. Predicting transcoding time for multiple transcoding parameters with different codecs and processing units is a challenging task, as it depends on many factors. This paper provides a novel and considerably fast method for transcoding time prediction using video content classification and neural network prediction. Our artificial neural network (ANN) model predicts the transcoding times of video segments for state-of-the-art video codecs based on transcoding parameters and content complexity. We evaluated our method for two video codecs/implementations (AVC/x264 and HEVC/x265) as part of large-scale HTTP Adaptive Streaming services. The ANN model of our method is able to predict the transcoding time by minimizing the mean absolute error (MAE) to 1.37 and 2.67 for x264 and x265 codecs, respectively. For x264, this is an improvement of 22% compared to the state of the art.
DDoS Attack Detection & Mitigation in SDNChao Chen
This document summarizes a presentation on detecting and mitigating distributed denial of service (DDoS) attacks in software-defined networks. It discusses using sFlow and the Floodlight controller to detect common DDoS attack types like ICMP floods, SYN floods, and DNS amplification. An application was developed in Python to classify attacks and push static flow entries to direct attack traffic to the sFlow collector for analysis. The scheme was tested in a Mininet virtual network and shown to successfully mitigate ICMP and SYN flood attacks. Future work includes testing DNS amplification and UDP floods, implementing adaptive sampling rates and thresholds, and designing an unblocking mechanism.
Labmeeting - 20150831 - Overhead and Performance of Low Latency Live Streamin...Syuan Wang
This document summarizes research into reducing latency for live video streaming using MPEG-DASH. It introduces MPEG-DASH and how using HTTP chunked transfer encoding and Gradual Decoding Refresh encoding can help lower latency compared to basic DASH. The paper describes experiments conducted to generate and distribute live content using these techniques and evaluate latency, finding they were able to achieve latency as low as 240ms.
This document is a dissertation submitted by Ameya Vashishth in partial fulfillment of a Bachelor of Technology degree. It discusses denial of service (DoS) attacks and mitigation techniques. The dissertation provides an overview of DoS attacks, describes different types of attacks like Smurf, ping flood, TCP SYN flood and UDP flood. It also discusses distributed DoS attacks and recommended tools to perform DDoS attacks. The document concludes with discussing various countermeasures that can be used to mitigate DoS and DDoS attacks.
MPEG Dynamic Adaptive Streaming over HTTP (DASH) is a new streaming standard that has been recently ratified as an international standard (IS). In comparison to other streaming systems, e.g., HTTP progressive download, DASH is able to handle varying bandwidth conditions providing smooth streaming. Furthermore, it enables NAT and Firewall traversal, flexible and scalable deployment as well as reduced infrastructure costs due to the reuse of existing Internet infrastructure components, e.g., proxies, caches, and Content Distribution Networks (CDN). Recently, the Hypertext Transfer Protocol Bis (httpbis) working group of the IETF has officially started the development of HTTP 2.0. Initially three major proposals have been submitted to the IETF i.e., Googles' SPDY, Microsofts' HTTP Speed+Mobility and Network-Friendly HTTP Upgrade, but SPDY has been chosen as working draft for HTTP 2.0. In this paper we implemented MPEG-DASH over HTTP 2.0 (i.e., SPDY), demonstrating its potential benefits and drawbacks. Moreover, several experimental evaluations have been performed that compare HTTP 2.0 with HTTP 1.1 and HTTP 1.0 in the context of DASH. In particular, the protocol overhead, the performance for different round trip times, and DASH with HTTP 2.0 in a lab test scenario has been evaluated in detail.
This document discusses various approaches for multimedia conferencing including centralized, distributed, and peer-to-peer architectures. It covers key considerations like transport protocols, audio and video quality, security, and floor control. It also discusses using IP multicast versus application-level multicast and different audio mixing and adaptive playout techniques.
The document discusses research on quantifying user satisfaction (QoE) in VoIP applications like Skype calls. It presents three key contributions:
1) Developing the first QoE measurement methodology based on analyzing large-scale Skype call data to correlate call duration with network quality factors like jitter and bit rate.
2) Proposing OneClick, a simple framework for crowdsourced QoE experiments based on user clicks to indicate dissatisfaction.
3) Introducing the first crowdsourcable QoE evaluation methodology to verify user judgments.
Scalable Service Oriented Architecture for Audio/Video ...Videoguy
The document summarizes research on developing a scalable service-oriented architecture for video conferencing using publish/subscribe event brokers to distribute real-time audio and video streams. It outlines the GlobalMMCS architecture, which separates media processing from delivery for scalability. Performance tests showed a single broker could support 1500 audio or 400 video participants, and distributed brokers improved scalability further.
Scalable Service Oriented Architecture for Audio/Video ...Videoguy
The document summarizes research on developing scalable videoconferencing systems using publish/subscribe event brokers to distribute audio and video streams. It proposes a service-oriented architecture with independently scalable components for media distribution, processing, and meeting management. Performance tests show a single broker can support up to 1500 users for audio-only conferences and 400 users for video conferences.
This document provides an overview and summary of a lecture on real-time communication over computer networks:
1. The lecture covered techniques for real-time multimedia communication implemented at the transport and application layers, including buffering to remedy jitter, forward error correction to recover lost packets, and interleaving to reduce the effects of packet loss bursts.
2. Key protocols discussed include RTP/RTCP for real-time media transport, RTSP for streaming media applications, and H.323 for videoconferencing.
3. Challenges for real-time multimedia over best-effort IP networks are meeting delay constraints for interactive applications while providing loss tolerance, and supporting large-scale multicast sessions.
This document provides a summary of key topics covered in a lecture on computer networks:
- Circuit switching and packet switching networking models, including their differences in allocating and sharing network resources.
- How the Internet evolved from millions of individual access networks connecting to each other through a hierarchical system of transit providers, internet exchange points, and content delivery networks.
- An overview of network security challenges like malware, denial of service attacks, packet sniffing, and IP spoofing. The importance of considering security in all layers of network design is also discussed.
HTTP/2 for Developers: How It Changes Developer's Life?
by Svetlin Nakov (SoftUni) - http://www.nakov.com
jProfessionals Conference - Sofia, 22-Nov-2015
Key new features in HTTP/2
- Multiplexing: multiple streams over a single connection
- Header compression: reuse headers from previous requests
- Sever push: multiple parallel responses for a single request
- Prioritization and flow control: resources have priorities
TCP Performance analysis Wireless Multihop NetworksAbhishek Kona
This document summarizes an experiment analyzing TCP performance over multi-hop wireless networks using a test bed. The experiment varied hop count, window size, and TCP variants. Results showed degradation in throughput with increased hops. Throughput peaked at certain window sizes depending on hops. WESTWOOD marginally outperformed other variants with small windows. Turning off TCP SACK gave better performance over 3 hops. Limitations included node availability and high data variance. Previous studies are difficult to emulate fully in real deployments.
This document presents research on Stheno, a middleware platform that integrates real-time (RT) and fault tolerance (FT) support in a peer-to-peer (P2P) system. Stheno was motivated by the need to support large-scale critical infrastructure systems with tight timing requirements. The document outlines Stheno's architecture, which leverages techniques such as resource reservation, priority-based threading, and replication to provide both RT and FT guarantees. An evaluation of a Stheno prototype found it can meet sub-second end-to-end latency and failover requirements, even under faults. The research contributes a novel RT+FT+P2P middleware and demonstrates its ability to support systems with mixed criticality
This document discusses implementing media-aware network elements (MANEs) on legacy devices to perform real-time adaptation of scalable video coded (SVC) bitstreams. It proposes using an ordinary WiFi router to intercept and adapt SVC streams in-network using a proxy approach. Evaluations show the router's CPU can support 4 parallel SVC streams with under 30% load and delay under 100ms, showing MANEs are feasible on existing home network devices.
Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adap...SmartenIT
Tobias Hoßfeld, Michael Seufert, Christian Sieber, Thomas Zinner
Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adaptive Streaming.
6th International Workshop on Quality of Multimedia Experience (QoMEX), Singapore, September 2014.
Abstract:
HTTP Adaptive Streaming (HAS) is employed by more and more video streaming services in the Internet. It allows to adapt the downloaded video quality to the current network conditions, and thus, avoids stalling (i.e., playback interruptions) to the greatest possible extend. The adaptation of video streams is done by switching between different quality representation levels, which influences the user perceived quality of the video stream. In this work, the influence of several adaptation parameters, namely, switch amplitude (i.e., quality level difference), switching frequency, and recency effects, on Quality of Experience (QoE) is investigated. Therefore, crowdsourcing experiments were conducted in order to collect subjective ratings for different adaptation-related test conditions. The results of these subjective studies indicate the influence of the adaptation parameters, and based on these findings a simplified QoE model for HAS is presented, which only relies on the switch amplitude and the playback time of each layer.
Open Source Software Tools for Synchrophasor ApplicationsLuigi Vanfretti
This document summarizes Luigi Vanfretti's work on developing open source software tools for synchrophasor applications. It discusses tools developed at KTH Royal Institute of Technology's SmarTS Lab for real-time hardware-in-the-loop simulation and prototyping of synchrophasor software and hardware. It also describes tools like S3DK and Khorjin that were created to help with synchrophasor application development by handling communication protocols and data management. The document outlines Vanfretti's motivation and the evolution of the SmarTS Lab's open source tools to support synchrophasor applications.
This document contains slides about multimedia networking. It discusses various types of multimedia applications like stored streaming, live streaming, and interactive real-time applications. It describes protocols used for multimedia like RTP, RTCP, and RTSP. Application-level techniques for multimedia over best-effort networks are also covered, such as client-side buffering and using UDP. Finally, it provides an example of setting up an interactive Internet phone call using these protocols.
This document discusses adapting dynamic adaptive streaming over HTTP (DASH) to work over information-centric networking (ICN). Some key points:
- DASH and ICN share similarities like client-initiated pulling of content chunks and support for efficient caching and replication.
- Open issues include mapping different naming schemes between DASH and ICN, bandwidth estimation over ICN, and caching efficiency.
- Combining DASH and CCN could provide benefits like efficient in-network caching and ability to request segments from multiple sources.
- Previous work has evaluated DASH over CCN and shown potential improvements from features like segment pipelining and using multiple network interfaces/links.
Overview of the Sun Remote Procedure Call (ONC RPC) technology
RPC allows a client application to call procedures in a different address space on the same or on a remote machine (= transfer of control and data to a different address space and process).
This means that RPC extends sockets with remote procedure call semantics. Thus RPC is an early approach for distributed applications.
Different flavors of RPC evolved over time. An early standard was set forth by Sun Microsystems with ONC RPC. It is defined in RFC1057 (protocol) and RFC4506 (XDR - data presentation).
The binder (formerly portmapper) is a central component of the RPC architecture. It is a deamon that serves as a registry for registering server procedures and allows a client to lookup procedures for being called remotely.
RPC defines three different call semantics. Maybe call semantics mean that a request may be lost without further notice by the RPC system. For applications requiring higher quality of service, at-least-once call semantics ensure that the call is successfully executed at least once. However, the call may be duplicated in case of packet loss. Exactly-once call semantics provide assurance that the call is executed at least and at most once.
A presentation talking about how we use Apache ActiveMQ (fuse-message-broker) at CERN for monitoring the Large Hadron Collider.
Presented at the FUSE community day - London 2010
In the last few years, video streaming facilities over TCP or UDP, such as YouTube, Facetime, Daily-motion, Mobile video calling have become more and more popular. The important
challenge in streaming broadcasting over the Internet is to spread the uppermost potential quality,
observe to the broadcasting play out time limitation, and efficiently and equally share the offered
bandwidth with TCP or UDP, and additional traffic types. This work familiarizes the Streaming
Media Data Congestion Control protocol (SMDCC), a new adaptive broadcasting streaming
congestion management protocol in which the connection’s data packets transmission frequency is
adjusted allowing to the dynamic bandwidth share of connection using SMDCC, the bandwidth share
of a connection is projected using algorithms similar to those introduced in TCP Westwood. SMDCC
avoids the Slow Jump phase in TCP. As a result, SMDCC does not show the pronounced rate
alternations distinguishing of modern TCP, so providing congestion control that is more appropriate
for streaming broadcasting applications. Besides, SMDCC is fair, sharing the bandwidth equitably
among a set of SMDCC connections. Main benefit is robustness when packet harms are due to
indiscriminate errors, which is typical of wireless links and is becoming an increasing concern due to
the emergence of wireless Internet access. In the presence of indiscriminate errors, SMDCC is also
approachable to TCP Tahoe and Reno (TTR). We provide simulation results using the ns3 simulator
for our protocol running together with TCP Tahoe and Reno.
This document summarizes the agenda and goals of a research group meeting on improving the quality of peer-to-peer (P2P) systems. The agenda includes welcome addresses from various deans and professors, presentations on P2P applications and quality in P2P systems. The goals of the research group are introduced, including identifying quality attributes of P2P systems, examining relationships between attributes, and prototyping mechanisms using reference scenarios in disaster recovery communications and software development. Researchers are assigned topics related to performance, costs, security, and other quality attributes.
This document provides an overview of a course on broadband and TCP/IP fundamentals. It discusses the topics that will be covered in each of the four sessions, including basics of TCP/IP networks, switching and scheduling, routing and transport, and applications and security. It also lists some recommended textbooks and references for the course.
Similar to Reliability extensions and multi hop evaluation of distributed protocol stacks (20)
Reliability extensions and multi hop evaluation of distributed protocol stacks
1. Reliability Extensions and Multi-Hop Evaluation of
Distributed Protocol Stacks
IEEE International Conference on Cyber, Physical and Social Computing (CPSCom 2013)
2013 IEEE 国际信息物理社会计算大会
August 20-23, 2013, Beijing, China
Peter Rothenpieler
Institute of Telematics, University of Lübeck
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
9. Experimental Setup
Wisebed Testbed located at University of Lübeck
Total: 43 nodes (2:1 ratio of Clients : Servers)
4 Experiments with a total runtime of 20h
Scenario: Building monitoring application
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
9
EU FP-7 Project (2008-2011): http://www.wisebed.eu
Questions
Does the DPS protocol work?
Does the DPS protocol have negative impact on
Packet reception rate (PRR)?
Latency (“Ping”)?
11. Visualization of routing path: All nodes send data to sink
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
11
Link between Servers (IP routing protocol)
Link between Server and Client (DPS protocol)
Server node
Client node
All nodes send their gathered sensor data (48 byte) to the
Sink using UDP every 30 seconds.
Example:
• Client A sends it‘s data to the sink
• Client A is attached to Server S1
• S1 forwards data to sink using IP-routing protocol
• Routing path:
• A S1 S2 S3 S4 Sink
• Distance: 5 hops
SINK
Client A
Server S1
Server S2
Server S3
Server S4
12. How long does the Discovery and Handshake take?
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
12
Time between first DISCOVERY message and connection successfully established
Clients send at least DISCOVERY messages every 30ms until
At least 3 DISCOVERY messages have been sent
At least 1 ADVERTISE was received
Afterwards, Three-way-Handshake starts (CONNECT, ALLOW, FINISH)
>90ms
(90+x) ms
(Transfer time
+ CSMA random backoff)
+(30+x) ms
(One additional DISCOVERY)
13. How long do DPS-connections last?
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
13
Clients and Servers exchange heartbeat messages every second
DPS connections are closed if no heartbeat messages was received for more than 4 seconds
If one node closes the connection, the other node closes the connection as well (within 4 seconds)
Most connections last 10-20 min
8% last longer than 2 hours
14. How many connections does each node establish?
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
14
A new connection is established after the heartbeat mechanism detected a disconnection
Clients establish exactly 1 connection to 1 Server
Servers establish several connections (1 to each Client)
Large differences between nodes (factor 3-4) are a result
of different positions (obstacles, interference, density, …)
Average: 1.1 Average: 2.0
15. Packet Reception Rate and Duplicate Packets
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
15
70% of all nodes have average PRR >95%
Node with lowest average PRR: 0x2100 89.2% (1 hop from sink)
Duplicate packets increase with distance
PRR does not increase with distance (obstacles, interference, density, …)
Far from sink Close to sink
16. Round-trip time: “Ping” all nodes in the network
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
16
Link between Servers (IP routing protocol)
Link between Server and Client (DPS protocol)
Server node
Client node
SINK
Client A
Server S1
Server S2
Server S3
Server S4
Client B
ICMPv6 Echo Request
ICMPv6 Echo Response
17. What is the round-trip time between each node and the sink?
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
17
100 ICMP Echo Request/Response Packets to each node in the network (48byte payload, same as UDP)
DPS has a negative influence on RTT (see paper from CPScom 2012)
But this influence in negligible in a multi-hop scenario (or even positive)
Upper quartile
Median
Lower quartile
Negative impact of DPS
Positive impact of DPS?
18. Summary
Motivation & Concept: Distributed Protocol Stacks
Protocol overview (incl. Reliability extensions)
Multi-hop evaluation
Connection establishment takes ~100ms
Connections last ~10-20min (or even more than 2h)
No negative impact on packet reception rate
Negative impact on round-trip time only measurable on
short distances
DPS Protocol works!
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
18
Available on slideshare:
http://bit.ly/1752ZIY
19. Summary
Motivation & Concept: Distributed Protocol Stacks
Protocol overview (incl. Reliability extensions)
Multi-hop evaluation
Connection establishment takes ~100ms
Connections last ~10-20min (or even more than 2h)
No negative impact on packet reception rate
Negative impact on round-trip time only measurable on
short distances
DPS Protocol works!
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
19
Available on slideshare:
http://bit.ly/1752ZIY
Thank you for your attention!
21. Code Size
Code size of native IPv6 implementation on JN5139 > 96 KB Flash
Use of IPv6 on JN5139 now possible (26.5 KB reduction)
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
Native IPv6
JN5139
DPS Client
JN5139
Native IPv6
JN5148
DPS Server
JN5148
Application 5.5 KB 3.8 KB
Os 43.9 KB 36.4 KB
IPv6 Stack 50.2 KB 10.1 KB 27.6 KB 27.6 KB
DPS - 13.6 KB - 8.0 KB
Σ 99.6 KB 73.1 KB 67.8 KB 75.8 KB
Relative
100 % -27 %
-26.5 KB
100 % + 12 %
+8.0 KB
ServerClient
21
22. What is the average packet reception rate (PRR)?
Dipl.-Inf. Peter Rothenpieler
rothenpieler@itm.uni-luebeck.de
http://www.itm.uni-luebeck.de/users/rothenpieler
22
Nodes send data via UDP No reliability!
Network size: 1-5 hops (average: 4.5 hops)
For Clients, the first hop uses the DPS protocol
All remaining hops use IPv6/6LoWPAN
57.1% of the time, PRR is higher than 95%