Abstract: CHOKe is a simple and stateless active queue management (AQM) scheme. Highly attractive property of Choke is that it can protect responsive TCP flows from unresponsive UDP flows. Packets currently queued in buffer, to penalize the high bandwidth flows. It can be implemented by using RED algorithm. In RED algorithm when packets arrives at a congested router. CHOKe draws a packet at a random from the FIFO buffer and compares it with the arriving packet. If both belong to same flow, then they are both dropped; else randomly chosen packet is left intact and arriving packet is admitted into the buffer with a probability that depend on the level of congestion. These algorithms are typically implemented in the transport protocols (e.g., TCP) of end-hosts. To ensure global fairness, such schemes require all users to adopt them and respond to network congestion properly.Keywords: CHOKe, Random Early Detection (RED), Congestion.
Title: Ephemeral Performance of Choke
Author: Suhitha K.C
ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Paper Publications
Token Based Packet Loss Control Mechanism for NetworksIJMER
This document summarizes a research paper that proposes a new congestion control mechanism using tokens. It begins with background on congestion control and modern IP networks. The proposed approach uses edge and core routers to write quality of service measures in packet headers as tokens. Tokers are interpreted by routers to gauge congestion, especially at edge routers. Based on tokens, edge routers can shape traffic from sources to reduce congestion. The mechanism aims to provide fairness while controlling packet loss. Key aspects discussed include stable token limit congestion control, core routers, edge routers, and how the approach compares to related work like CSFQ.
11.a study of congestion aware adaptive routing protocols in manetAlexander Decker
This document summarizes and compares several congestion-aware routing protocols for mobile ad hoc networks (MANETs). It discusses the Congestion Adaptive Routing Protocol (CRP), which uses bypass routes to avoid congested areas and splits traffic between primary and bypass routes adaptively. It also describes the Efficient Congestion Adaptive Routing Protocol (ECARP), which modifies AODV parameters to improve congestion handling, and the Congestion Aware Routing plus Rate Adaptation (CARA) protocol, which establishes routes around congested areas. Finally, it discusses the Congestion Aware Routing Protocol for Mobile ad hoc networks (CARM), which uses a weighted channel delay metric to measure
For further details contact:
N.RAJASEKARAN B.E M.S 9841091117,9840103301.
IMPULSE TECHNOLOGIES,
Old No 251, New No 304,
2nd Floor,
Arcot road ,
Vadapalani ,
Chennai-26.
Gateway Forwarding Schemes For Manet-Internet Connectivityijsrd.com
In the real world one of the most important challenge for the broad implementation of mobile ad hoc network (MANET) technology is the finding way to capably interconnect them with the Internet. Yet, such interconnections are very difficult due to differences in mobility, addressing and routing between MANETs and reside IP networks. Imprecise address and routing techniques are hard to integrate. In this paper we propose the half tunnels as a powerful transition technique to integrate various networks. In this paper, we will also discuss some existing solutions like default routes host route etc to interconnect MANETs with the Internet, but on analysis we find them lacking in robustness and flexibility. For example, many solutions do not consider the presence of multiple gateways, and in such scenarios they either fail, or are less efficient due to the lack of multi-homing capabilities.
Packet losses at IP network are common behavior at
the time of congestion. The TCP traffic is explained as in
terms of load and capacity. The load should be measured as
number of sender actively competes for a bottleneck link and
the capacity as the total network buffering available to those
senders. Though there are many congestion mechanism
already in practice like congestion window, slow start,
congestion avoidance, fast transmit but still we see erratic
behavior when there is a large traffic. The TCP protocol that
controls sources send rates degrades rapidly if the network
cannot store at least a few packets per active connection. Thus
the amount of router buffer space required for good
performance scales with the number of active connections
and the bandwidth utilization by each active connections. As
in the current practice, the buffer space does not scale in this
way and router drops the packet without looking at bandwidth
utilization of each connections. The result is global
synchronization and phase effect as well as packet from the
unlucky sender will be frequently dropped. The simultaneous
requirements of low queuing delay and of large buffer
memories for large numbers of connections pose a problem.
Routers should enforce a dropping policy by proportional to
the bandwidth utilization by each active connection. Router
will provision the buffering mechanism when processing slows
down. This study explains the existing problem with drop-tail
and RED routers and proposes the new mechanism to predict
the effective bandwidth utilization of the clients depending
on their history of utilization and drop the packet in different
pattern after analyzing the network bandwidth utilization at
each specific interval of time
A Novel Rebroadcast Technique for Reducing Routing Overhead In Mobile Ad Hoc ...IOSR Journals
This document presents a novel rebroadcast technique called Neighbor Coverage based Probabilistic Rebroadcast (NCPR) protocol to reduce routing overhead in mobile ad hoc networks. The NCPR protocol calculates a rebroadcast delay based on the number of common neighbors between nodes to prioritize dissemination of neighbor information. It also calculates a rebroadcast probability based on additional neighbor coverage ratio and connectivity factor to reduce unnecessary rebroadcasts while maintaining network connectivity. The protocol is implemented by enhancing the AODV routing protocol in NS-2 to reduce overhead from hello packets and neighbor lists in route requests. Its performance is evaluated under varying network sizes, traffic loads, and packet loss conditions.
Cost Effective Routing Protocols Based on Two Hop Neighborhood Information (2...Eswar Publications
Ad hoc networks are collections of mobile nodes communicating with each other using wireless media without any fixed infrastructure. During both route discovery and traversal of route-reply packets from destination to source,
broadcast of packets is required which incurs huge message cost. The present article deals with the message cost
reduction during transmission of route-reply from destination to source. Also the redundancy that is visible within the 2-hop neighborhood of a node is minimized during broadcasting of route-reply. This improves the average lifetime of network nodes by decreasing the possibility of network partition. The scheme of 2NI can be used with any reactive routing protocol in MANETs.
This document analyzes the effect of node density on different routing protocols under FTP and HTTP applications. It simulates scenarios with varying node densities (20-130 nodes) using routing protocols AODV, DSR, GRP and OLSR. Key quality of service (QoS) metrics - throughput, delay, network load and packet delivery ratio - are evaluated and compared. The results show that OLSR generally performs best in terms of throughput and delay for both FTP and HTTP applications. GRP performs best for network load, while AODV has the highest packet delivery ratio for FTP. In conclusion, OLSR is the best overall routing protocol for supporting FTP and HTTP applications in mobile ad-hoc networks according to
Token Based Packet Loss Control Mechanism for NetworksIJMER
This document summarizes a research paper that proposes a new congestion control mechanism using tokens. It begins with background on congestion control and modern IP networks. The proposed approach uses edge and core routers to write quality of service measures in packet headers as tokens. Tokers are interpreted by routers to gauge congestion, especially at edge routers. Based on tokens, edge routers can shape traffic from sources to reduce congestion. The mechanism aims to provide fairness while controlling packet loss. Key aspects discussed include stable token limit congestion control, core routers, edge routers, and how the approach compares to related work like CSFQ.
11.a study of congestion aware adaptive routing protocols in manetAlexander Decker
This document summarizes and compares several congestion-aware routing protocols for mobile ad hoc networks (MANETs). It discusses the Congestion Adaptive Routing Protocol (CRP), which uses bypass routes to avoid congested areas and splits traffic between primary and bypass routes adaptively. It also describes the Efficient Congestion Adaptive Routing Protocol (ECARP), which modifies AODV parameters to improve congestion handling, and the Congestion Aware Routing plus Rate Adaptation (CARA) protocol, which establishes routes around congested areas. Finally, it discusses the Congestion Aware Routing Protocol for Mobile ad hoc networks (CARM), which uses a weighted channel delay metric to measure
For further details contact:
N.RAJASEKARAN B.E M.S 9841091117,9840103301.
IMPULSE TECHNOLOGIES,
Old No 251, New No 304,
2nd Floor,
Arcot road ,
Vadapalani ,
Chennai-26.
Gateway Forwarding Schemes For Manet-Internet Connectivityijsrd.com
In the real world one of the most important challenge for the broad implementation of mobile ad hoc network (MANET) technology is the finding way to capably interconnect them with the Internet. Yet, such interconnections are very difficult due to differences in mobility, addressing and routing between MANETs and reside IP networks. Imprecise address and routing techniques are hard to integrate. In this paper we propose the half tunnels as a powerful transition technique to integrate various networks. In this paper, we will also discuss some existing solutions like default routes host route etc to interconnect MANETs with the Internet, but on analysis we find them lacking in robustness and flexibility. For example, many solutions do not consider the presence of multiple gateways, and in such scenarios they either fail, or are less efficient due to the lack of multi-homing capabilities.
Packet losses at IP network are common behavior at
the time of congestion. The TCP traffic is explained as in
terms of load and capacity. The load should be measured as
number of sender actively competes for a bottleneck link and
the capacity as the total network buffering available to those
senders. Though there are many congestion mechanism
already in practice like congestion window, slow start,
congestion avoidance, fast transmit but still we see erratic
behavior when there is a large traffic. The TCP protocol that
controls sources send rates degrades rapidly if the network
cannot store at least a few packets per active connection. Thus
the amount of router buffer space required for good
performance scales with the number of active connections
and the bandwidth utilization by each active connections. As
in the current practice, the buffer space does not scale in this
way and router drops the packet without looking at bandwidth
utilization of each connections. The result is global
synchronization and phase effect as well as packet from the
unlucky sender will be frequently dropped. The simultaneous
requirements of low queuing delay and of large buffer
memories for large numbers of connections pose a problem.
Routers should enforce a dropping policy by proportional to
the bandwidth utilization by each active connection. Router
will provision the buffering mechanism when processing slows
down. This study explains the existing problem with drop-tail
and RED routers and proposes the new mechanism to predict
the effective bandwidth utilization of the clients depending
on their history of utilization and drop the packet in different
pattern after analyzing the network bandwidth utilization at
each specific interval of time
A Novel Rebroadcast Technique for Reducing Routing Overhead In Mobile Ad Hoc ...IOSR Journals
This document presents a novel rebroadcast technique called Neighbor Coverage based Probabilistic Rebroadcast (NCPR) protocol to reduce routing overhead in mobile ad hoc networks. The NCPR protocol calculates a rebroadcast delay based on the number of common neighbors between nodes to prioritize dissemination of neighbor information. It also calculates a rebroadcast probability based on additional neighbor coverage ratio and connectivity factor to reduce unnecessary rebroadcasts while maintaining network connectivity. The protocol is implemented by enhancing the AODV routing protocol in NS-2 to reduce overhead from hello packets and neighbor lists in route requests. Its performance is evaluated under varying network sizes, traffic loads, and packet loss conditions.
Cost Effective Routing Protocols Based on Two Hop Neighborhood Information (2...Eswar Publications
Ad hoc networks are collections of mobile nodes communicating with each other using wireless media without any fixed infrastructure. During both route discovery and traversal of route-reply packets from destination to source,
broadcast of packets is required which incurs huge message cost. The present article deals with the message cost
reduction during transmission of route-reply from destination to source. Also the redundancy that is visible within the 2-hop neighborhood of a node is minimized during broadcasting of route-reply. This improves the average lifetime of network nodes by decreasing the possibility of network partition. The scheme of 2NI can be used with any reactive routing protocol in MANETs.
This document analyzes the effect of node density on different routing protocols under FTP and HTTP applications. It simulates scenarios with varying node densities (20-130 nodes) using routing protocols AODV, DSR, GRP and OLSR. Key quality of service (QoS) metrics - throughput, delay, network load and packet delivery ratio - are evaluated and compared. The results show that OLSR generally performs best in terms of throughput and delay for both FTP and HTTP applications. GRP performs best for network load, while AODV has the highest packet delivery ratio for FTP. In conclusion, OLSR is the best overall routing protocol for supporting FTP and HTTP applications in mobile ad-hoc networks according to
This document summarizes a research paper that proposes CafRep, an adaptive congestion control protocol for delay-tolerant networks (DTNs). CafRep uses implicit heuristics based on contact and resource congestion to offload traffic from congested parts of the network to less congested areas. It also adaptively replicates messages at lower rates in different parts of the network with non-uniform congestion levels. The paper evaluates CafRep across three real mobility traces and shows it outperforms state-of-the-art DTN forwarding algorithms in maintaining high delivery rates while keeping low delays and packet loss, especially in congested networks.
IRJET-A Survey on Red Queue Mechanism for Reduce Congestion in Wireless NetworkIRJET Journal
This document summarizes several queue management mechanisms for congestion control in wireless networks, including Random Early Detection (RED) and variants. RED detects congestion by tracking average queue length and dropping packets probabilistically. Variants like Fuzzy Logic RED (FLRED) and Hemi-Rise Cloud Model (CRED) aim to improve RED by addressing its sensitivity to parameters and nonlinearity. Explicit Congestion Control (ECC) and Explicit Non-Congestion Notification (ENCN) modify TCP headers to signal congestion or non-congestion. Three section Random Early Detection (TRED) divides the queue into three sections to calculate dropping probability nonlinearly. These variants aim to more effectively control congestion and improve performance
Load Balancing and Congestion Control in MANETijsrd.com
The document summarizes a proposed load balancing and congestion control algorithm for mobile ad hoc networks (MANETs). The algorithm uses a coordinated multi-path routing approach where multiple paths between source and destination nodes are established. When congestion is detected at an intermediate node, a congestion notification message is sent to the source node. The source node then distributes data packets across the multiple paths randomly to balance load and avoid congested areas of the network. The algorithm aims to reduce end-to-end delay, packet loss, and imbalance in energy consumption among nodes through coordinated load balancing across multiple routes. Simulation results show the approach is effective at alleviating network congestion compared to single-path routing.
CONGESTION AWARE LINK COST ROUTING FOR MANETSIJCNCJournal
Due to the dynamic topology, self-configuration and decentralized nature of Mobile Ad hoc Network
(MANET), it provides many benefits in wireless networks and is easy to deploy. But the transmission of
data over ad hoc networks has elevated many technical issues for successful routing. Congestion is one of
the important issues which cause performance degradation of a network, due to long delay and high packet
loss. This paper proposes a Congestion aware Link Cost Routing for MANET where the protocol finds a
path with optimized linked cost based on SNR, Link delay, and the and remaining battery power. Along
with this optimization, in this protocol, every node finds its congestion status and participates in the route
discovery on the basis of its status. Data forwarding is also done based on the congestion status at the time
of forwarding. The protocol results in better performance in terms of packet delivery fraction, end to end
delay, throughput, and packet drop when compared to existing protocols.
The document proposes a Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. CPCRT aims to distinguish between packet loss due to link failure versus other causes like congestion. It takes a cross-layer approach using information from the physical, MAC, and application layers. The proposed method also aims to conserve power during packet transmission by adjusting transmission power levels based on received signal strength. Simulation results show that CPCRT can better utilize resources and conserve power during congestion control compared to other approaches.
This document discusses a proposed congestion control mechanism called Network Border Protocol (NBP) that aims to prevent congestion collapse and unfairness in networks. NBP works by having edge routers monitor and control the ingress rates of individual flows to prevent packets from entering the network faster than they can leave. It uses feedback exchanged between ingress and egress routers to inform them of flow rates. While adding complexity to edge routers, NBP's approach aims to isolate this within the network borders and not require changes to end systems or transport protocols. The key components of NBP include its rate control algorithm, use of leaky bucket algorithms at ingress routers, and feedback control between edge routers.
This document summarizes a research paper that proposes a novel cross-layer routing technique for mobile ad hoc networks. The technique calculates both signal strength and node mobility to select the most efficient and stable path for data transmission. It aims to improve on traditional ad hoc routing protocols like AODV by considering both link quality metrics from the physical layer (signal strength) and node mobility. The proposed method selects routes based on signal strength if mobility is high, and on traditional hop count if mobility is low, in order to find paths that reduce link failure and improve throughput.
Analysis of Random Based Mobility Model using TCP Traffic for AODV and DSDV M...ijsrd.com
In Mobile Ad hoc network (MANETS), no fixed infrastructure is available. Different wireless hosts are free to move from one location to another without any centralized administration, so, the topology changes rapidly or unpredictably. Every node operates as router as well as an end system. Routing in MANETs has been a challenging task ever since the wireless networks came into existence. The major reason for this is continues changes in network topology because of high degree of node mobility. The MANET routing protocols have mainly two classes: Proactive routing (or table-driven routing) protocols and Reactive routing (or on-demand routing) protocols. In this paper, we have analyzed various Random based mobility models: Random Waypoint model, Random Walk model, Random Direction model and Probabilistic Random Walk model using AODV and DSDV protocols in Network Simulator (NS 2.35). The performance comparison of MANET mobility models have been analyzed by varying number of nodes using traffic TCP. The comparative conclusions are drawn on the basis of various performance metrics such as: Routing Overhead (packets), Packet Delivery Fraction (%), Normalized Routing Load, Average End-to-End Delay (milliseconds) and Packet Loss (%).
The document discusses challenges with using TCP in mobile ad hoc networks (MANETs) and evaluates potential solutions. Specifically, it finds that:
1) TCP performs poorly in MANETs due to high packet loss from route failures and wireless errors, which TCP misinterprets as congestion.
2) TCP variants like Westwood and Jersey that more accurately estimate bandwidth perform better but are not sufficient.
3) A new transport protocol like ATP that is rate-based rather than window-based and leverages intermediate nodes may better address MANET issues.
A survey on routing algorithms and routing metrics for wireless mesh networksMohammad Siraj
This document summarizes a survey on routing algorithms and metrics for wireless mesh networks. It discusses the requirements of efficient mesh routing protocols including being distributed, adaptable to topology changes, loop-free, secure, scalable, and supporting quality of service. It reviews several important proactive routing protocols including destination-sequenced distance-vector routing, optimized link state routing, and mesh networking routing protocol. It also discusses reactive routing protocols and examples like dynamic source routing and ad hoc on-demand distance vector routing. Finally, it examines routing metrics and their impact on the performance of wireless mesh networks.
A survey on mac strategies for cognitive radio networksAbir Hossain
The document presents CoRe-MAC, a MAC protocol for cooperative relaying in wireless networks that extends CSMA/CA. It uses reactive relay selection, where a relay is selected only if direct transmission between the source and destination fails. This avoids overhead when cooperation is not needed. Potential relays listen to direct transmissions and can act as relays if needed. Relay selection involves relays applying to relay and the destination selecting the best relay. Simulation results show CoRe-MAC performs similar to CSMA/CA for good SNR but improves throughput and reliability over larger distances by enabling cooperation when needed.
This document summarizes key concepts from Chapter 3 of the textbook on transport layer protocols:
1. The transport layer provides logical communication between processes running on different hosts, abstracting the underlying network infrastructure. It multiplexes data from multiple sockets and demultiplexes received data to the appropriate socket.
2. UDP and TCP are the main transport protocols in the Internet. UDP is connectionless while TCP provides reliable, connection-oriented data transfer using sequence numbers, acknowledgments, and congestion control.
3. TCP uses congestion control including a congestion window, additive increase/multiplicative decrease, and slow start to dynamically control the sender's transmission rate based on detected packet loss as a signal of
Comparative Analysis of Drop Tail, Red and NLRED Congestion Control Algorithm...EvaObinna
Congestion in a network may occur when the load on the network is greater than the capacity of the network and consequently, performance degrades. Congestion control is a technique and mechanisms that can either prevent congestion before it happens, or remove congestion after it has happened. This work presents a comparative analysis of Drop Tail, RED and NLRED congestion control algorithm and performed a simulation experiment to show their relative effectiveness. The experiment was done using NS2 simulator on the basis of End-to-End Delay, Throughput, Packet Drop, and Packet Delivery Ratio in a wired network. The simulation result showed that NLRED performs best in high congestion network, while in low cohesive network, Drop Tail gives a good result. Drop Tail, RED and NLRED was also analysed in real audio traffic and the entire results showed that in congested network, NLRED and RED are better while in low congested network Drop Tail is better. This is because in heavy congested network, congestion avoidance mechanism aids the network to gain better performance while in low congested network unnecessary computation avoidance mechanisms degrades the performance of the network. If parameters are set effectively in RED, it will be the best queuing mechanism for that particular network. However, it is of great importance to know which congestion control mechanism is suitable for each network and traffic.
Multi-path TCP (MP-TCP) has the prospective to
significantly advance applications performance by using multiple
paths evidently. Multipath TCP was intended and employed as a
backward compatible replacement for TCP. For this reason, it
exposes the standard socket API to the applications that cannot
control the utilization of the different paths. This is a key feature
for applications that are unaware of the multipath nature of the
network. On the contrary, this is a limitation for applications
that could benefit from specific knowledge to use multiple paths
in a way that fits their needs. Therefore, hosts are often
connected by multiple paths, but TCP restricts communications
to a single path per transport connection. Resource usage within
the network would be more efficient where these multiple paths
able to be used concurrently. This should enhance user
experience through improved resilience to network failure and
higher throughput. In this paper, we have focused on MPTCP
and discussed the performance issues and its solution. We believe
our concept will be useful for future works of MPTCP
performance evaluation.
Fairness Comparison of TCP Variants over Proactive and Reactive Routing Proto...IJECEIAES
Mobile ad hoc networks (MANETs) are applicable in an infrastructureless environment where the mobile devices act as routers and intermediate nodes are used to transfer segments to their final destination. As Transmission control protocol (TCP) was originated for Internet with fundamentally different properties, faces serious challenges when used in mobile ad hoc networks. TCP functionality degrades, due to special properties of MANET such as route failure because of significant change of network topology and link errors. TCP uses Congestion Control Algorithms; TCP Vegas is one of them which claim to have better throughput comparing with other TCP variants in a wired network. Fairness issues of TCP Variants in MANET including existing routing protocol are still unsolved. To determine the best TCP Variants in MANET environment over renowned routing protocol is the main objective of this paper. A Study on the throughput fairness of TCP Variants namely, Vegas, Reno, New Reno, SACK, FACK, and Cubic are performed via simulation experiment using network simulator (ns-2) over existing routing protocol, named, AODV, AOMDV, DSDV, and DSR. This fairness evaluation of TCP flows arranged a contrast medium for the TCP Variants using stated routing protocol in MANET. However, TCP Vegas obtain unfair throughput in MANET. The simulation results show that TCP Reno outperforms other TCP variants under DSDV routing protocol.
Virtual circuits are connections over packet-switched networks that appear as dedicated physical links between devices. They are established through configuration and allow higher-level protocols to avoid dealing with packetization of data. While virtual circuits resemble circuit switching, factors like queue lengths and load can cause variable performance unlike dedicated circuits. Examples of protocols that provide virtual circuits include TCP, X.25, Frame Relay, and ATM. Virtual circuits can be either switched, established on demand, or permanent, preconfigured for repeated use.
SCTP-MANET NEW EXTENSION OF SCTP PROTOCOL FOR THE OPTIMIZATION OF MANET PERFO...ijwmn
Ad Hoc mobile networks are constituted of nodes that move freely without a centralized administration.
These nodes contribute in the routing of data packets that are sent by a source. This happens when the
latter is not capable of reaching its destination. On the other hand, their mobility causes recurrent
breakdowns of the routing paths notably with sparse MANET. In order to optimize the performance of such
networks, we suggest a new extension of protocols: Stream Control Transmission Protocols (SCTP) named
SCTP-MANET. Their main function is therefore to improve the availability of the links in sparse MANET
protocols. This could be achieved by a better integration of Multihoming. With this aim in mind, this new
extension is based on a cross-layer interface between transport and routing layers as well as the use of
specific messages.
This document presents a QoS-based packet scheduling algorithm for hybrid wireless networks. It proposes using the Earliest Deadline First (EDF) algorithm to schedule packets for online conference applications and the Least Slack Time First algorithm to schedule packets for online video applications. The goal is to reduce transmission delay and improve QoS. It implements this scheduling approach using the NS2 network simulator. The scheduling algorithm classifies packets by application type and places them in queues. EDF and Least Slack Time are then used to schedule packets from each queue to minimize delay for multimedia applications over hybrid wireless networks.
PERFORMANCE EVALUATION OF SELECTED E2E TCP CONGESTION CONTROL MECHANISM OVER ...ijwmn
TCP is one of the main protocols that govern the Internet traffic nowadays. However, it suffers significant
performance degradation over wireless links. Since wireless networks are leading the communication
technologies recently, it is imperative to introduce effective solutions for the TCP congestion control
mechanisms over such networks. In this research four End-to-End TCP implementations are discussed,
they are TCP Westwood, Hybla, Highspeed, and NewReno. The performance of these variants is compared
using LTE emulated environment in terms of throughput, delay, and fairness. Ns-3 simulator is used to
simulate the LTE networks environment. The simulation results showed that TCP Highspeed achieves the
best throughput results. Although TCP Westwood recorded the lowest latency values comparing to others,
it behaved unfairly among different traffic flows. Moreover, TCP Hybla demonstrated the best fairness
behaviour among other TCP variants
The document describes a study that examined the effects of scapular stabilization exercises on type 2 scapular dyskinesia in subjects with shoulder impingement. The study involved 7 male patients who underwent a protocol of closed kinetic chain exercises focused on the scapula 3 times per week for 2 weeks. Outcome measures of shoulder pain/disability (SPADI) and lateral scapular slide were taken before and after the intervention. The results found a statistically significant improvement in both outcome measures following the scapular stabilization exercises, suggesting that the exercises are effective in treating type 2 scapular dyskinesia.
This document summarizes a research paper that proposes CafRep, an adaptive congestion control protocol for delay-tolerant networks (DTNs). CafRep uses implicit heuristics based on contact and resource congestion to offload traffic from congested parts of the network to less congested areas. It also adaptively replicates messages at lower rates in different parts of the network with non-uniform congestion levels. The paper evaluates CafRep across three real mobility traces and shows it outperforms state-of-the-art DTN forwarding algorithms in maintaining high delivery rates while keeping low delays and packet loss, especially in congested networks.
IRJET-A Survey on Red Queue Mechanism for Reduce Congestion in Wireless NetworkIRJET Journal
This document summarizes several queue management mechanisms for congestion control in wireless networks, including Random Early Detection (RED) and variants. RED detects congestion by tracking average queue length and dropping packets probabilistically. Variants like Fuzzy Logic RED (FLRED) and Hemi-Rise Cloud Model (CRED) aim to improve RED by addressing its sensitivity to parameters and nonlinearity. Explicit Congestion Control (ECC) and Explicit Non-Congestion Notification (ENCN) modify TCP headers to signal congestion or non-congestion. Three section Random Early Detection (TRED) divides the queue into three sections to calculate dropping probability nonlinearly. These variants aim to more effectively control congestion and improve performance
Load Balancing and Congestion Control in MANETijsrd.com
The document summarizes a proposed load balancing and congestion control algorithm for mobile ad hoc networks (MANETs). The algorithm uses a coordinated multi-path routing approach where multiple paths between source and destination nodes are established. When congestion is detected at an intermediate node, a congestion notification message is sent to the source node. The source node then distributes data packets across the multiple paths randomly to balance load and avoid congested areas of the network. The algorithm aims to reduce end-to-end delay, packet loss, and imbalance in energy consumption among nodes through coordinated load balancing across multiple routes. Simulation results show the approach is effective at alleviating network congestion compared to single-path routing.
CONGESTION AWARE LINK COST ROUTING FOR MANETSIJCNCJournal
Due to the dynamic topology, self-configuration and decentralized nature of Mobile Ad hoc Network
(MANET), it provides many benefits in wireless networks and is easy to deploy. But the transmission of
data over ad hoc networks has elevated many technical issues for successful routing. Congestion is one of
the important issues which cause performance degradation of a network, due to long delay and high packet
loss. This paper proposes a Congestion aware Link Cost Routing for MANET where the protocol finds a
path with optimized linked cost based on SNR, Link delay, and the and remaining battery power. Along
with this optimization, in this protocol, every node finds its congestion status and participates in the route
discovery on the basis of its status. Data forwarding is also done based on the congestion status at the time
of forwarding. The protocol results in better performance in terms of packet delivery fraction, end to end
delay, throughput, and packet drop when compared to existing protocols.
The document proposes a Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. CPCRT aims to distinguish between packet loss due to link failure versus other causes like congestion. It takes a cross-layer approach using information from the physical, MAC, and application layers. The proposed method also aims to conserve power during packet transmission by adjusting transmission power levels based on received signal strength. Simulation results show that CPCRT can better utilize resources and conserve power during congestion control compared to other approaches.
This document discusses a proposed congestion control mechanism called Network Border Protocol (NBP) that aims to prevent congestion collapse and unfairness in networks. NBP works by having edge routers monitor and control the ingress rates of individual flows to prevent packets from entering the network faster than they can leave. It uses feedback exchanged between ingress and egress routers to inform them of flow rates. While adding complexity to edge routers, NBP's approach aims to isolate this within the network borders and not require changes to end systems or transport protocols. The key components of NBP include its rate control algorithm, use of leaky bucket algorithms at ingress routers, and feedback control between edge routers.
This document summarizes a research paper that proposes a novel cross-layer routing technique for mobile ad hoc networks. The technique calculates both signal strength and node mobility to select the most efficient and stable path for data transmission. It aims to improve on traditional ad hoc routing protocols like AODV by considering both link quality metrics from the physical layer (signal strength) and node mobility. The proposed method selects routes based on signal strength if mobility is high, and on traditional hop count if mobility is low, in order to find paths that reduce link failure and improve throughput.
Analysis of Random Based Mobility Model using TCP Traffic for AODV and DSDV M...ijsrd.com
In Mobile Ad hoc network (MANETS), no fixed infrastructure is available. Different wireless hosts are free to move from one location to another without any centralized administration, so, the topology changes rapidly or unpredictably. Every node operates as router as well as an end system. Routing in MANETs has been a challenging task ever since the wireless networks came into existence. The major reason for this is continues changes in network topology because of high degree of node mobility. The MANET routing protocols have mainly two classes: Proactive routing (or table-driven routing) protocols and Reactive routing (or on-demand routing) protocols. In this paper, we have analyzed various Random based mobility models: Random Waypoint model, Random Walk model, Random Direction model and Probabilistic Random Walk model using AODV and DSDV protocols in Network Simulator (NS 2.35). The performance comparison of MANET mobility models have been analyzed by varying number of nodes using traffic TCP. The comparative conclusions are drawn on the basis of various performance metrics such as: Routing Overhead (packets), Packet Delivery Fraction (%), Normalized Routing Load, Average End-to-End Delay (milliseconds) and Packet Loss (%).
The document discusses challenges with using TCP in mobile ad hoc networks (MANETs) and evaluates potential solutions. Specifically, it finds that:
1) TCP performs poorly in MANETs due to high packet loss from route failures and wireless errors, which TCP misinterprets as congestion.
2) TCP variants like Westwood and Jersey that more accurately estimate bandwidth perform better but are not sufficient.
3) A new transport protocol like ATP that is rate-based rather than window-based and leverages intermediate nodes may better address MANET issues.
A survey on routing algorithms and routing metrics for wireless mesh networksMohammad Siraj
This document summarizes a survey on routing algorithms and metrics for wireless mesh networks. It discusses the requirements of efficient mesh routing protocols including being distributed, adaptable to topology changes, loop-free, secure, scalable, and supporting quality of service. It reviews several important proactive routing protocols including destination-sequenced distance-vector routing, optimized link state routing, and mesh networking routing protocol. It also discusses reactive routing protocols and examples like dynamic source routing and ad hoc on-demand distance vector routing. Finally, it examines routing metrics and their impact on the performance of wireless mesh networks.
A survey on mac strategies for cognitive radio networksAbir Hossain
The document presents CoRe-MAC, a MAC protocol for cooperative relaying in wireless networks that extends CSMA/CA. It uses reactive relay selection, where a relay is selected only if direct transmission between the source and destination fails. This avoids overhead when cooperation is not needed. Potential relays listen to direct transmissions and can act as relays if needed. Relay selection involves relays applying to relay and the destination selecting the best relay. Simulation results show CoRe-MAC performs similar to CSMA/CA for good SNR but improves throughput and reliability over larger distances by enabling cooperation when needed.
This document summarizes key concepts from Chapter 3 of the textbook on transport layer protocols:
1. The transport layer provides logical communication between processes running on different hosts, abstracting the underlying network infrastructure. It multiplexes data from multiple sockets and demultiplexes received data to the appropriate socket.
2. UDP and TCP are the main transport protocols in the Internet. UDP is connectionless while TCP provides reliable, connection-oriented data transfer using sequence numbers, acknowledgments, and congestion control.
3. TCP uses congestion control including a congestion window, additive increase/multiplicative decrease, and slow start to dynamically control the sender's transmission rate based on detected packet loss as a signal of
Comparative Analysis of Drop Tail, Red and NLRED Congestion Control Algorithm...EvaObinna
Congestion in a network may occur when the load on the network is greater than the capacity of the network and consequently, performance degrades. Congestion control is a technique and mechanisms that can either prevent congestion before it happens, or remove congestion after it has happened. This work presents a comparative analysis of Drop Tail, RED and NLRED congestion control algorithm and performed a simulation experiment to show their relative effectiveness. The experiment was done using NS2 simulator on the basis of End-to-End Delay, Throughput, Packet Drop, and Packet Delivery Ratio in a wired network. The simulation result showed that NLRED performs best in high congestion network, while in low cohesive network, Drop Tail gives a good result. Drop Tail, RED and NLRED was also analysed in real audio traffic and the entire results showed that in congested network, NLRED and RED are better while in low congested network Drop Tail is better. This is because in heavy congested network, congestion avoidance mechanism aids the network to gain better performance while in low congested network unnecessary computation avoidance mechanisms degrades the performance of the network. If parameters are set effectively in RED, it will be the best queuing mechanism for that particular network. However, it is of great importance to know which congestion control mechanism is suitable for each network and traffic.
Multi-path TCP (MP-TCP) has the prospective to
significantly advance applications performance by using multiple
paths evidently. Multipath TCP was intended and employed as a
backward compatible replacement for TCP. For this reason, it
exposes the standard socket API to the applications that cannot
control the utilization of the different paths. This is a key feature
for applications that are unaware of the multipath nature of the
network. On the contrary, this is a limitation for applications
that could benefit from specific knowledge to use multiple paths
in a way that fits their needs. Therefore, hosts are often
connected by multiple paths, but TCP restricts communications
to a single path per transport connection. Resource usage within
the network would be more efficient where these multiple paths
able to be used concurrently. This should enhance user
experience through improved resilience to network failure and
higher throughput. In this paper, we have focused on MPTCP
and discussed the performance issues and its solution. We believe
our concept will be useful for future works of MPTCP
performance evaluation.
Fairness Comparison of TCP Variants over Proactive and Reactive Routing Proto...IJECEIAES
Mobile ad hoc networks (MANETs) are applicable in an infrastructureless environment where the mobile devices act as routers and intermediate nodes are used to transfer segments to their final destination. As Transmission control protocol (TCP) was originated for Internet with fundamentally different properties, faces serious challenges when used in mobile ad hoc networks. TCP functionality degrades, due to special properties of MANET such as route failure because of significant change of network topology and link errors. TCP uses Congestion Control Algorithms; TCP Vegas is one of them which claim to have better throughput comparing with other TCP variants in a wired network. Fairness issues of TCP Variants in MANET including existing routing protocol are still unsolved. To determine the best TCP Variants in MANET environment over renowned routing protocol is the main objective of this paper. A Study on the throughput fairness of TCP Variants namely, Vegas, Reno, New Reno, SACK, FACK, and Cubic are performed via simulation experiment using network simulator (ns-2) over existing routing protocol, named, AODV, AOMDV, DSDV, and DSR. This fairness evaluation of TCP flows arranged a contrast medium for the TCP Variants using stated routing protocol in MANET. However, TCP Vegas obtain unfair throughput in MANET. The simulation results show that TCP Reno outperforms other TCP variants under DSDV routing protocol.
Virtual circuits are connections over packet-switched networks that appear as dedicated physical links between devices. They are established through configuration and allow higher-level protocols to avoid dealing with packetization of data. While virtual circuits resemble circuit switching, factors like queue lengths and load can cause variable performance unlike dedicated circuits. Examples of protocols that provide virtual circuits include TCP, X.25, Frame Relay, and ATM. Virtual circuits can be either switched, established on demand, or permanent, preconfigured for repeated use.
SCTP-MANET NEW EXTENSION OF SCTP PROTOCOL FOR THE OPTIMIZATION OF MANET PERFO...ijwmn
Ad Hoc mobile networks are constituted of nodes that move freely without a centralized administration.
These nodes contribute in the routing of data packets that are sent by a source. This happens when the
latter is not capable of reaching its destination. On the other hand, their mobility causes recurrent
breakdowns of the routing paths notably with sparse MANET. In order to optimize the performance of such
networks, we suggest a new extension of protocols: Stream Control Transmission Protocols (SCTP) named
SCTP-MANET. Their main function is therefore to improve the availability of the links in sparse MANET
protocols. This could be achieved by a better integration of Multihoming. With this aim in mind, this new
extension is based on a cross-layer interface between transport and routing layers as well as the use of
specific messages.
This document presents a QoS-based packet scheduling algorithm for hybrid wireless networks. It proposes using the Earliest Deadline First (EDF) algorithm to schedule packets for online conference applications and the Least Slack Time First algorithm to schedule packets for online video applications. The goal is to reduce transmission delay and improve QoS. It implements this scheduling approach using the NS2 network simulator. The scheduling algorithm classifies packets by application type and places them in queues. EDF and Least Slack Time are then used to schedule packets from each queue to minimize delay for multimedia applications over hybrid wireless networks.
PERFORMANCE EVALUATION OF SELECTED E2E TCP CONGESTION CONTROL MECHANISM OVER ...ijwmn
TCP is one of the main protocols that govern the Internet traffic nowadays. However, it suffers significant
performance degradation over wireless links. Since wireless networks are leading the communication
technologies recently, it is imperative to introduce effective solutions for the TCP congestion control
mechanisms over such networks. In this research four End-to-End TCP implementations are discussed,
they are TCP Westwood, Hybla, Highspeed, and NewReno. The performance of these variants is compared
using LTE emulated environment in terms of throughput, delay, and fairness. Ns-3 simulator is used to
simulate the LTE networks environment. The simulation results showed that TCP Highspeed achieves the
best throughput results. Although TCP Westwood recorded the lowest latency values comparing to others,
it behaved unfairly among different traffic flows. Moreover, TCP Hybla demonstrated the best fairness
behaviour among other TCP variants
The document describes a study that examined the effects of scapular stabilization exercises on type 2 scapular dyskinesia in subjects with shoulder impingement. The study involved 7 male patients who underwent a protocol of closed kinetic chain exercises focused on the scapula 3 times per week for 2 weeks. Outcome measures of shoulder pain/disability (SPADI) and lateral scapular slide were taken before and after the intervention. The results found a statistically significant improvement in both outcome measures following the scapular stabilization exercises, suggesting that the exercises are effective in treating type 2 scapular dyskinesia.
The document summarizes key points from the 2017-18 Union Budget of India presented by Finance Minister Arun Jaitley. The budget focused on 10 themes: farmers, rural population, youth, poor/underprivileged, infrastructure, financial sector, digital economy, fiscal management, tax proposals, and political party funding. Key allocations and policy changes are outlined for agriculture, rural development, education, healthcare, infrastructure, energy, taxation, and other sectors. The budget was positively received in stock markets but rail stocks fell due to proposed rail allocation. Certain items like cigarettes and LED components will be costlier while online rail tickets and LNG will be cheaper after the budget.
This document outlines the need for a large-scale transformation program at JSC Sovereign Wealth Fund Samruk-Kazyna. It notes that Kazakhstan's development strategy aims to become a top 30 developed nation by 2050 but this will require a major breakthrough in investment growth and productivity. Samruk-Kazyna owns key national assets and must improve operational and investment performance to help achieve this goal, but current targets are insufficient. As a result, Samruk-Kazyna has developed a transformation program focused on improving value in portfolio companies, restructuring the portfolio, and reforming governance.
The document discusses different aspects of digital photography including camera modes, capturing images, file storage, and lighting. It explains that manual mode gives the photographer more control over shutter speed and aperture while automatic mode lets the camera control settings. It describes camera components like the viewfinder, lens, image sensor, aperture, and shutter that are used to capture images. File storage can be in RAW or JPEG formats with different storage sizes, and pros and cons of each format are provided. Different types of lighting like flash, exposure, color, and white balance are discussed and how they impact photo quality.
This document summarizes a study that examined the effectiveness of retro walking (backward walking) in patients with chronic osteoarthritis of the knee. 30 patients with grade 3 knee osteoarthritis underwent 10 minutes of retro walking per day on an inclined treadmill for 10 days. Outcome measures assessed before and after the intervention included pain, stiffness, physical function via the WOMAC index, knee extension lag, dynamic balance, and parameters of forward walking. The results showed statistically significant improvements in all outcome measures following the retro walking intervention. The study concluded that retro walking is an effective approach for reducing symptoms and improving physical function in patients with osteoarthritis of the knee.
Malaria is caused by plasmodium parasites and transmitted via mosquito bites. Symptoms include fever, vomiting and organ dysfunction. Diagnosis involves blood smear examination and antigen testing. Treatment depends on the plasmodium species and involves antimalarial drugs like chloroquine, primaquine, and artemisinin. Prevention focuses on mosquito control with nets and repellents. The case report describes a 26-year-old male admitted with malaria symptoms diagnosed as P. vivax malaria based on lab tests. He was treated with intravenous fluids and antimalarial medications and discharged with medication and follow up instructions.
This document is a curriculum vitae for Moses Murima Ngige, a Kenyan national currently residing in Dubai in the United Arab Emirates. It outlines his personal details, contact information, objective, skills, work experience, education, and hobbies. Ngige has over 8 years of experience in sales, marketing, and supervisory roles in Kenya and the UAE for companies in various industries including retail, FMCG distribution, and B2B wholesale. He is seeking new opportunities to utilize his skills and experience.
A novel token based approach towards packet loss controleSAT Journals
This document summarizes a research paper that proposes a novel congestion control mechanism called Stable Token-Limited Congestion Control (STLCC). STLCC monitors inter-domain traffic rates and limits the number of tokens to control congestion and improve network performance. The authors implemented STLCC in a prototype application and found that it was effective at controlling packet loss and improving network performance compared to other congestion control methods. They concluded that STLCC can automatically measure and reduce congestion to allocate network resources stably.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Recital Study of Various Congestion Control Protocols in wireless networkiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document discusses and compares several congestion control protocols for wireless networks, including TCP, RCP, and RCP+. It implemented an enhanced version of RCP+ in the NS-2 simulator. Simulation results showed that the proposed approach achieved higher throughput and packet delivery ratio than TCP and RCP+ in a wireless network with 10-50 nodes, with performance degrading as the number of nodes increased beyond 20 due to increased congestion. The paper analyzes the mechanisms and equations of each protocol and argues the proposed approach combines benefits of improved AIMD and RCP+ to address their individual shortcomings.
Assessing Buffering with Scheduling Schemes in a QoS Internet RouterIOSR Journals
This document examines different scheduling algorithms that could be used with RIO-C penalty enforcement buffering in a multi-queue QoS router to improve network performance. It simulates priority, round robin, and weighted round robin scheduling with RIO-C buffering. The results show that priority scheduling achieved the lowest loss rates, with 29.46% scheduler drop rate and 14.95% RED loss rate. Round robin was second with 29.53% and 10.50% losses. Weighted round robin was third with 30.28% and 3.04% losses. The document concludes that a network seeking quality of service could adopt priority scheduling with RIO-C admission control.
The transport layer accepts data from the session layer, breaks it into packets, and delivers the packets to the network layer. It provides end-to-end communication and ensures reliable delivery of data. The network interface layer sends and receives TCP/IP packets on the network medium. It encompasses the data link and physical layers of the OSI model. TCP/IP is independent of the specific network technology.
Comparative Analysis of Green Algorithm within Active Queue Management for Mo...ijtsrd
The Queue Management Techniques play an important role in improving the Quality of Service in Mobile Ad hoc Networks. The need of congestion control and Queue management is inevitable in Mobile Ad hoc Network. Understanding and analyzing the latest AQM Techniques give an insight to improving throughput, packet loss rate, average end to end delay and other parameters that severely affect the performance. The performance of mobile ad hoc networks is evaluated by varying the Channel Error Rate, Bandwidth and Delay at different fragment sizes of different traffic flows. The proposed method performs the network analysis of new Routing protocols. The work proposes to evaluate various Active Queue Management Techniques in a multi traffic environment i.e., sources generating both TCP and UDP traffic classes. The UDP is propagated via CBR and TCP is propagated via FTP. The implementation of the proposed queue management technique has been done in NS 2. In the proposed work we have make NS 2 compatible with GREEN by integrating source code into the ns 2 installation files and using various AQMs in comparison with GREEN to calculate the throughput at various Bandwidths across network. Using various AQMs in comparison with GREEN we have calculated the throughput at various Delays across the network and we have also calculated the throughput at various channels Error Rate across the network. The proposed method has been compared with other primitive AQM techniques so that a repository of best available results can be obtained for design and research purposes. The proposed method has outperformed the existing queue management techniques in number of scenarios. Zulai Khan | Rashmi Raj ""Comparative Analysis of Green Algorithm within Active Queue Management for Mobile Ad Hoc Network"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23950.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/23950/comparative-analysis-of-green-algorithm-within-active-queue-management-for-mobile-ad-hoc-network/zulai-khan
Iaetsd an effective approach to eliminate tcp incastIaetsd Iaetsd
This document proposes an Incast Congestion Control for TCP (ICTCP) scheme to eliminate TCP incast collapse in datacenter environments. TCP incast collapse occurs when multiple synchronized servers send data to the same receiver in parallel, overwhelming the switch buffer and causing packet loss. ICTCP is a receiver-side approach that proactively adjusts the TCP receive window size of connections to control their aggregate burstiness and prevent switch buffer overflow before packet loss occurs. It estimates available bandwidth and uses this as a quota to coordinate receive window increases. For each connection, the receive window is adjusted based on the ratio of the difference between measured and expected throughput. This allows adaptive tuning of receive windows to meet sender throughput needs while avoiding congest
CPCRT: Crosslayered and Power Conserved Routing Topology for congestion Cont...IOSR Journals
The document describes a proposed Crosslayered and Power Conserved Routing Topology (CPCRT) for congestion control in mobile ad hoc networks. The CPCRT aims to improve transmission performance by distinguishing between packet loss due to link failure versus other causes, while also conserving power used for packet transmission. It builds upon an earlier Crosslayered Routing Topology (CRT) approach by incorporating power conservation. The CPCRT is intended to identify the root cause of packet loss, avoid unnecessary congestion handling from link failures, allow congestion handling at specific high-traffic nodes rather than all nodes, and optimize resource and power usage for packet routing in mobile ad hoc networks.
An Approach for Enhanced Performance of Packet Transmission over Packet Switc...ijceronline
With the increased use of real time applications, there is a need for improved network traffic and bandwidth management. Switches are being used by computer networks for enabling connection between those hosts which are not connected by a direct link. When two or more than two host attempt to transmit packet at the same time, collision in data packets occurred. In this paper an optimized performance of local area network in terms of collision count and some other parameter have been investigated using simulation model. Simulation results have been obtained in different network scenarios by varying the number of devices in the network.
Study on Different Mechanism for Congestion Control in Real Time Traffic for ...IRJET Journal
This document discusses congestion control mechanisms for real-time traffic in mobile ad hoc networks (MANETs). It describes two main types of congestion control: closed-loop control, which detects and responds to congestion after it occurs using feedback; and open-loop control, which aims to prevent congestion before it happens without feedback. The document also examines traffic shaping mechanisms like leaky bucket and token bucket algorithms that can regulate network traffic and prevent congestion. Finally, it outlines some challenges of congestion in best-effort networks and different approaches to congestion control, including end-to-end flow control and router-based mechanisms.
This document discusses an efficient CSFQ (Eff-CSFQ) algorithm proposed for congestion management that improves upon regular CSFQ. It summarizes existing queuing techniques like RED, FRED, and CSFQ that are used to control packet transmission and dropping. The proposed Eff-CSFQ combines priority queuing and max-min fairness with CSFQ, treating real-time traffic like VoIP as higher priority and using multiple queues for such flows at core routers. This improves fairness and avoids congestion compared to the single FIFO queue used in regular CSFQ. The document aims to simulate and analyze the performance of Eff-CSFQ versus regular CSFQ, RED and FRED using metrics like packet delivery fraction, end-to
Efficient and Fair Bandwidth Allocation AQM Scheme for Wireless NetworksCSCJournals
Heterogeneous Wireless Networks are considered nowadays as one of the potential areas in research and development. The traffic management’s schemes that have been used at the fusion points between the different wireless networks are classical and conventional. This paper is focused on developing a novel scheme to overcome the problem of traffic congestion in the fusion point router interconnected the heterogeneous wireless networks. The paper proposed an EF-AQM algorithm which provides an efficient and fair allocation of bandwidth among different established flows. Finally, the proposed scheme developed, tested and validated through a set of experiments to demonstrate the relative merits and capabilities of a proposed scheme
Review on buffer management schemes for packet queues in wired & wireless net...IJERA Editor
Mobile AdHoc Network (MANET) is a wireless network with a set of mobile nodes that can communicate with
each other with no access point and without any fixed infrastructure. But mobile devices usually have limited
resources (battery power, memory, CPU) which limit their transmission range. Hence, in order to conserve the
limited resource, it is highly desirable that transmission should be as efficient as possible. MANET can be
implemented in any environment because of its dynamic nature. For routing of information packets queuing is
done at the buffer and transferred through intermediate nodes to the destination on priority basis which help to
improve the overall network performance. This paper provides a review of various buffer management schemes
for packet queues in wired & wireless networks (specialy MANET).
IRJET-A Survey on congestion control with TCP networkIRJET Journal
This document summarizes various mechanisms for congestion control in computer networks. It begins with an introduction to congestion and its impacts. It then classifies congestion control schemes into several categories such as window-based vs. rate-based, unicast vs. multicast, and end-to-end vs. router-supported. Several popular congestion control protocols are described, including TCP, RAP, TFRC, and TEAR. Window-based multicast congestion control approaches like RLA and MTCP are also summarized. The document provides an overview of different congestion control techniques in computer networks.
Comparative Analysis of Different TCP Variants in Mobile Ad-Hoc Network partha pratim deb
The document analyzes the performance of different TCP variants (New Reno, Reno, Tahoe) with MANET routing protocols (AODV, DSR, TORA) through simulation. It finds that in scenarios with 3 and 5 nodes, AODV has better throughput than DSR and TORA for all TCP variants. Throughput decreases for all variants as node count increases. New Reno provides multiple packet loss recovery and is the best choice for AODV in MANETs due to its consistent performance with changes in node count. Further analysis of additional protocols and TCP variants is recommended.
The congestion control within the TCP (Transmission Control Protocol) plays a critical role in
amending data rate to evade congestion from happening possibilities. Based on TCP communication sender
not only guarantees the successful packet delivery, but also maintains the correct sequence of packets by
receiving the frequent acknowledgement from the receiver. In this research we proposed a congestion
control scheme with modified TCP and queue length variation with OLSR routing protocol in MANET. The
TCP protocol performance is modified by forwarding busy channel signals to predecessor nodes through
intermediate nodes in network. The congestion is controlled by that novel method of detecting the node is
busy or ready for communication. If the communication is start in network and the possibility if congestion
is arise, then in that case the queue length is handle the possibility of congestion. The congestion is
minimized due to awaring about the channel busy status and nodes buffer status or queue status. The TCP
protocol is able to handle the congestion situation but i.e. completely based on acknowledgement of receiver
and also not very effective to control it. The proposed TCP congestion control OLSR routing is improves
the network performance by reducing packet loss. The performance of network is measure through
performance metrics like throughput, PDF and Routing overhead in different node density scenarios. The
performance of proposed scheme is provides the better results.
Transport control protocols for Wireless sensor networksRushin Shah
The document discusses traditional transport control protocols and their feasibility for use in wireless sensor networks. It describes how TCP and UDP are generally not suitable for WSNs due to their overhead and lack of features like congestion control that are needed in low power lossy networks. The document then outlines key considerations for designing new transport protocols for WSNs, including performing congestion control and reliable delivery, simplifying connection establishment, avoiding packet loss to reduce energy waste, and providing fairness across nodes. Transport protocols for WSNs need hop-by-hop approaches and mechanisms to reduce buffer usage and packet loss while conserving energy.
The transport layer provides efficient, reliable, and cost-effective process-to-process delivery by making use of network layer services. The transport layer works through transport entities to achieve its goal of reliable delivery between application processes. It provides an interface for applications to access its services.
zkStudyClub - LatticeFold: A Lattice-based Folding Scheme and its Application...Alex Pruden
Folding is a recent technique for building efficient recursive SNARKs. Several elegant folding protocols have been proposed, such as Nova, Supernova, Hypernova, Protostar, and others. However, all of them rely on an additively homomorphic commitment scheme based on discrete log, and are therefore not post-quantum secure. In this work we present LatticeFold, the first lattice-based folding protocol based on the Module SIS problem. This folding protocol naturally leads to an efficient recursive lattice-based SNARK and an efficient PCD scheme. LatticeFold supports folding low-degree relations, such as R1CS, as well as high-degree relations, such as CCS. The key challenge is to construct a secure folding protocol that works with the Ajtai commitment scheme. The difficulty, is ensuring that extracted witnesses are low norm through many rounds of folding. We present a novel technique using the sumcheck protocol to ensure that extracted witnesses are always low norm no matter how many rounds of folding are used. Our evaluation of the final proof system suggests that it is as performant as Hypernova, while providing post-quantum security.
Paper Link: https://eprint.iacr.org/2024/257
Essentials of Automations: Exploring Attributes & Automation ParametersSafe Software
Building automations in FME Flow can save time, money, and help businesses scale by eliminating data silos and providing data to stakeholders in real-time. One essential component to orchestrating complex automations is the use of attributes & automation parameters (both formerly known as “keys”). In fact, it’s unlikely you’ll ever build an Automation without using these components, but what exactly are they?
Attributes & automation parameters enable the automation author to pass data values from one automation component to the next. During this webinar, our FME Flow Specialists will cover leveraging the three types of these output attributes & parameters in FME Flow: Event, Custom, and Automation. As a bonus, they’ll also be making use of the Split-Merge Block functionality.
You’ll leave this webinar with a better understanding of how to maximize the potential of automations by making use of attributes & automation parameters, with the ultimate goal of setting your enterprise integration workflows up on autopilot.
"NATO Hackathon Winner: AI-Powered Drug Search", Taras KlobaFwdays
This is a session that details how PostgreSQL's features and Azure AI Services can be effectively used to significantly enhance the search functionality in any application.
In this session, we'll share insights on how we used PostgreSQL to facilitate precise searches across multiple fields in our mobile application. The techniques include using LIKE and ILIKE operators and integrating a trigram-based search to handle potential misspellings, thereby increasing the search accuracy.
We'll also discuss how the azure_ai extension on PostgreSQL databases in Azure and Azure AI Services were utilized to create vectors from user input, a feature beneficial when users wish to find specific items based on text prompts. While our application's case study involves a drug search, the techniques and principles shared in this session can be adapted to improve search functionality in a wide range of applications. Join us to learn how PostgreSQL and Azure AI can be harnessed to enhance your application's search capability.
In our second session, we shall learn all about the main features and fundamentals of UiPath Studio that enable us to use the building blocks for any automation project.
📕 Detailed agenda:
Variables and Datatypes
Workflow Layouts
Arguments
Control Flows and Loops
Conditional Statements
💻 Extra training through UiPath Academy:
Variables, Constants, and Arguments in Studio
Control Flow in Studio
"Frontline Battles with DDoS: Best practices and Lessons Learned", Igor IvaniukFwdays
At this talk we will discuss DDoS protection tools and best practices, discuss network architectures and what AWS has to offer. Also, we will look into one of the largest DDoS attacks on Ukrainian infrastructure that happened in February 2022. We'll see, what techniques helped to keep the web resources available for Ukrainians and how AWS improved DDoS protection for all customers based on Ukraine experience
ScyllaDB is making a major architecture shift. We’re moving from vNode replication to tablets – fragments of tables that are distributed independently, enabling dynamic data distribution and extreme elasticity. In this keynote, ScyllaDB co-founder and CTO Avi Kivity explains the reason for this shift, provides a look at the implementation and roadmap, and shares how this shift benefits ScyllaDB users.
Connector Corner: Seamlessly power UiPath Apps, GenAI with prebuilt connectorsDianaGray10
Join us to learn how UiPath Apps can directly and easily interact with prebuilt connectors via Integration Service--including Salesforce, ServiceNow, Open GenAI, and more.
The best part is you can achieve this without building a custom workflow! Say goodbye to the hassle of using separate automations to call APIs. By seamlessly integrating within App Studio, you can now easily streamline your workflow, while gaining direct access to our Connector Catalog of popular applications.
We’ll discuss and demo the benefits of UiPath Apps and connectors including:
Creating a compelling user experience for any software, without the limitations of APIs.
Accelerating the app creation process, saving time and effort
Enjoying high-performance CRUD (create, read, update, delete) operations, for
seamless data management.
Speakers:
Russell Alfeche, Technology Leader, RPA at qBotic and UiPath MVP
Charlie Greenberg, host
"Scaling RAG Applications to serve millions of users", Kevin GoedeckeFwdays
How we managed to grow and scale a RAG application from zero to thousands of users in 7 months. Lessons from technical challenges around managing high load for LLMs, RAGs and Vector databases.
LF Energy Webinar: Carbon Data Specifications: Mechanisms to Improve Data Acc...DanBrown980551
This LF Energy webinar took place June 20, 2024. It featured:
-Alex Thornton, LF Energy
-Hallie Cramer, Google
-Daniel Roesler, UtilityAPI
-Henry Richardson, WattTime
In response to the urgency and scale required to effectively address climate change, open source solutions offer significant potential for driving innovation and progress. Currently, there is a growing demand for standardization and interoperability in energy data and modeling. Open source standards and specifications within the energy sector can also alleviate challenges associated with data fragmentation, transparency, and accessibility. At the same time, it is crucial to consider privacy and security concerns throughout the development of open source platforms.
This webinar will delve into the motivations behind establishing LF Energy’s Carbon Data Specification Consortium. It will provide an overview of the draft specifications and the ongoing progress made by the respective working groups.
Three primary specifications will be discussed:
-Discovery and client registration, emphasizing transparent processes and secure and private access
-Customer data, centering around customer tariffs, bills, energy usage, and full consumption disclosure
-Power systems data, focusing on grid data, inclusive of transmission and distribution networks, generation, intergrid power flows, and market settlement data
Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
An English 🇬🇧 translation of a presentation to the speech I gave about the main changes brought by CCS TSI 2023 at the biggest Czech conference on Communications and signalling systems on Railways, which was held in Clarion Hotel Olomouc from 7th to 9th November 2023 (konferenceszt.cz). Attended by around 500 participants and 200 on-line followers.
The original Czech 🇨🇿 version of the presentation can be found here: https://www.slideshare.net/slideshow/hlavni-novinky-souvisejici-s-ccs-tsi-2023-2023-1695/269688092 .
The videorecording (in Czech) from the presentation is available here: https://youtu.be/WzjJWm4IyPk?si=SImb06tuXGb30BEH .
Northern Engraving | Nameplate Manufacturing Process - 2024Northern Engraving
Manufacturing custom quality metal nameplates and badges involves several standard operations. Processes include sheet prep, lithography, screening, coating, punch press and inspection. All decoration is completed in the flat sheet with adhesive and tooling operations following. The possibilities for creating unique durable nameplates are endless. How will you create your brand identity? We can help!
Discover top-tier mobile app development services, offering innovative solutions for iOS and Android. Enhance your business with custom, user-friendly mobile applications.
Must Know Postgres Extension for DBA and Developer during MigrationMydbops
Mydbops Opensource Database Meetup 16
Topic: Must-Know PostgreSQL Extensions for Developers and DBAs During Migration
Speaker: Deepak Mahto, Founder of DataCloudGaze Consulting
Date & Time: 8th June | 10 AM - 1 PM IST
Venue: Bangalore International Centre, Bangalore
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Ephemeral Performance of Choke
1. ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Vol. 2, Issue 1, pp: (230-235), Month: April 2015 – September 2015, Available at: www.paperpublications.org
Page | 230
Paper Publications
Ephemeral Performance of Choke
Suhitha K.C
M P Nachimuthu M Jaganathan Engineering College, Chennimalai, Erode, India
Abstract: CHOKe is a simple and stateless active queue management (AQM) scheme. Highly attractive property of
Choke is that it can protect responsive TCP flows from unresponsive UDP flows. Packets currently queued in
buffer, to penalize the high bandwidth flows. It can be implemented by using RED algorithm. In RED algorithm
when packets arrives at a congested router. CHOKe draws a packet at a random from the FIFO buffer and
compares it with the arriving packet. If both belong to same flow, then they are both dropped; else randomly
chosen packet is left intact and arriving packet is admitted into the buffer with a probability that depend on the
level of congestion. These algorithms are typically implemented in the transport protocols (e.g., TCP) of end-
hosts. To ensure global fairness, such schemes require all users to adopt them and respond to network congestion
properly.
Keywords: CHOKe, Random Early Detection (RED), Congestion.
1. INTRODUCTION
CHOKe is a simple and stateless active queue management (AQM) scheme. Apart from low operational overhead, a
highly attractive property of CHOKe is that it can protect responsive TCP flows from unresponsive UDP flows. Choke is
able to bound both bandwidth share and buffer share a possible aggregate of UDP Traffic flow on a link. When packets
arrives at a congested router. CHOKe draws a packet at a random from the FIFO buffer and compares it with the arriving
packet. If both belong to same flow, then they are both dropped; else randomly chosen packet is left intact and arriving
packet is admitted into the buffer with a probability that depend on the level of congestion.
2. ADAPTIVE RED
The RED active queue management algorithm allows network operators to simultaneously achieve high throughput and
low average delay. The resulting average queue length is quite sensitive to the level of congestion and to the RED
parameter settings, and is therefore not predictable in advance. Delay being a major component of the quality of service
delivered to their customers, network operators would naturally like to have a rough a priori estimate of the average
delays in their congested routers; to achieve such predictable average delays with RED would require constant tuning of
the parameters to adjust to current traffic conditions.
Goal of paper is to solve this problem with minimal changes to the overall RED algorithm. We make several algorithmic
modifications to this proposal, while leaving the basic idea intact, and then evaluate its performance using simulation. We
find that this revised version of Adaptive RED, which can be implemented as a simple extension within RED routers,
removes the sensitivity to parameters that affect RED’s performance and can reliably achieve a specified target average
queue length in a wide variety of traffic scenarios. Based on extensive simulations, we believe that Adaptive RED is
sufficiently robust for deployment in routers.
This paper presents Random Early Detection (RED) gateways for congestion avoidance in packet-switched networks. The
gateway detects incipient congestion by computing the average queue size. The gateway could notify connections of
congestion either by dropping packets arriving at the gateway or by setting a bit in packet headers.
2. ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Vol. 2, Issue 1, pp: (230-235), Month: April 2015 – September 2015, Available at: www.paperpublications.org
Page | 231
Paper Publications
When the average queue size exceeds a preset threshold, the gateway drops or marks each arriving packet with a certain
probability, where the exact probability is a function of the average queue size.
RED gateways keep the average queue size low while allowing occasional bursts of packets in the queue. During
congestion, the probability that the gateway notifies a particular connection to reduce its window is roughly proportional
to that connection’s share of the bandwidth through the gateway. RED gateways are designed to accompany a transport-
layer congestion control protocol such as TCP. The RED gateway has no bias against burst traffic and avoids the global
synchronization of many connections decreasing their window at the same time. Simulations of a TCP/IP network are
used to illustrate the performance of RED gateways
3. WHY THE INTERNET TRAFFIC IS BURST IN SHORT TIME SCALES?
Internet exhibits multifaceted business and correlation structure over a wide span of time scales. This is focus on shorter
scales, typically less than 100-1000 milliseconds. Our objective is to identify the actual mechanisms that are responsible
for creating busty traffic in those scales. We show that TCP self-clocking, joint with queuing in the network, can shape
the packet inter arrivals of a TCP connection in a two-level ON-OFF pattern. This structure creates strong correlations and
burstiness in time scales that extend up to the Round- Trip Time (RTT) of the connection. This is more important for bulk
transfers that have a large bandwidth-delay product relative to their window size. Also, the aggregation of many flows,
without rescaling their packet inter arrivals, does not converge to a Poisson stream, as one might expect from classical
superposition results. Instead, the burstiness in those scales can be significantly reduced by TCP pacing. In particular, we
focus on the importance of the minimum pacing timer, and show that a 10-millisecond timer would be too coarse for
removing short-scale burstiness, while A 1-millisecond timer would be clients to make the almost as smooth as a Poisson
stream in sub-RTT scales
To achieve satisfying user experiences of diverse applications, quality of service (QoS) guaranteed mechanisms such as
per-flow queuing are required in routers. Deployment of per-flow queuing in high-speed routers is considered as a great
challenge since its industrial brute-force implementation is not scalable with the increase of the number of flows. In this
study, the authors propose a dynamic queues haring (DQS) mechanism to enable scalable per-flow queuing. DQS keeps
isolation of each concurrent active flow by sharing a small number of queues instead of maintaining a dedicated queue for
each in-progress flow, which is novel compared to the existing methods. According to DQS, a physical queue is created
and assigned to an active flow upon the arrival of its first packet, and is destroyed upon the departure of the last packet in
the queue. The authors combine hash method with binary sorting tree to construct and manage the dynamic mapping
between active flows and physical queues, which significantly reduce the number of required physical queues from
millions to hundreds and makes per-flow queuing feasible for high-performance routers.
Per-flow queuing mechanism suffers a great scalability problem with the dramatic increase in the number of in-progress
flows. In this paper, we first confirm the measurement result that the number of concurrent active flows in the routers is
typically in hundreds even though there may be tens of thousands of flows in-progress. Based on this observation, we
have proposed a DQS mechanism to implement scalable per-flow queuing in high-performance routers.
4. ISSUES AND TRENDS IN ROUTER DESIGN
Routers knit together the constituent networks of the global Internet, creating the illusion of a unified whole. While their
primary role is to transfer packets from a set of input links to a set of output links, they must also deal with heterogeneous
link technologies, provide scheduling support for differential service, and participate in Complex distributed algorithms to
generate globally coherent routing tables. These demands, along with an insatiable need for bandwidth in the Internet,
complicate their design. Routers are found at every level in the Internet. Routers in access networks allow homes and
small businesses to connect to an Internet service provider (ISP). Routers in enterprise networks link tens of thousands of
computers within a campus or an enterprise. Routers in the backbone are not usually directly accessible to end systems.
Instead, they link together ISPs and enterprise networks with long distance trunks. The rapid growth of the Internet has
created different challenges for routers in backbone, enterprise, and access networks. The backbone needs routers capable
of routing at high speeds on a few links. Enterprise routers should have low cost per port and a large number of ports, be
3. ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Vol. 2, Issue 1, pp: (230-235), Month: April 2015 – September 2015, Available at: www.paperpublications.org
Page | 232
Paper Publications
easy to configure, and support quality of service (QoS). Finally, access routers should support many heterogeneous high-
speed ports and a variety of protocols at each port, and try to bypass the central office voice switch.
This article presents the design issues and trends that arise in these three classes of routers. The following section
describes the structure of a generic router. The section after that discusses design issues in backbone, enterprise, and
access routers. Present some recent advances and trends in router design. Finally conclude with a description of some
open problems. Note that our main topic of discussion is packet forwarding; routing protocols, which create the
forwarding tables, are dealt with only in passing
A recently proposed active queue management, CHOKe, aims to protect TCP from UDP flows. Simulations have shown
that as UDP rate increases, its bandwidth share initially rises but eventually drops. We derive an approximate model of
CHOKe and show that, provided the number of TCP flows is large, the UDP bandwidth share peaks at(e+1)1 = 0:269
when the UDP input rate is slightly larger than the link capacity, and drops to zero as UDP input rate tends to infinity,
regardless of the TCP algorithm.
TCP is believed to be largely responsible for preventing congestion collapse while Internet has undergone dramatic
growth in the last decade. Indeed, numerous measurements have consistently shown that more than 90% of traffic on the
current Internet is still TCP packets, which, fortunately, are congestion controlled. Without a proper incentive structure,
this state is fragile and can be disrupted by the growing number of non-rate-adaptive (e.g., UDP-based) applications that
can monopolize network bandwidth to the detriment of rate-adaptive applications. This has motivated several active queue
management schemes.
5. MAXIMUM AND ASYMPTOTIC UDP THROUGHPUT UNDER CHOKE
A recently proposed active queue management, Choke, is stateless, simple to implement, yet surprisingly effective in
protecting TCP from UDP flows. We present an equilibrium model of TCP/CHOKe. We prove that, provided the number
of TCP flow is large, the UDP bandwidth share peaks at (+ 1) 1 = 0 269 when UDP input rate is slightly larger than link
capacity, and drops to zero as UDP input rate tends to infinity. We clarify the spatial characteristics of the leaky buffer
under CHOKe that produce this throughput behavior. Specifically, we prove that, as UDP input rate increases, even
though the total number of UDP packets in the queue increases, their spatial distribution becomes more and more
concentrated near the tail of the queue, and drops rapidly to zero toward the head of the queue. In stark contrast to a non
leaky FIFO buffer where UDP bandwidth shares would approach 1 as its input rate increases without bound, under
CHOKe, UDP simultaneously maintains a large number of packets in the queue and receives a vanishingly small
bandwidth share, the mechanism through which CHOKe protects TCP flows.
TCP is believed to be largely responsible for preventing congestion collapse while the Internet has undergone dramatic
growth in the last decade. Indeed, numerous measurements have consistently shown that more than 90% of the traffic on
the current Internet is still TCP packets, which, fortunately, are congestion controlled
6. APPROXIMATE FAIRNESS THROUGH LIMITED FLOW LIST.
Most of router mechanisms proposed for fair bandwidth sharing lack either (1) simplicity due to complexity of intricate
per flow management of all connections (e.g., WFQ, SFQ), (2) heterogeneity due to a design targeting a specific traffic
type, e.g., RED-PD and Fair RED (FRED) or (3) robustness due to requirement for proper router configurations (e.g.,
CSFQ). All of these severely impact the scalability of the schemes. This paper proposes a novel router fairness
mechanism, namely Approximate Fairness through Partial Finish Time (AFpFT). Key to the design of AFpFT is a tag
field the value of which defines the position of the packet in an aggregate queue shared by all flows. The specific of tag
computation depends on the router’s role—edge or inner— to the flow. While gateways closest to traffic source manage
all flows, successive or inner routers only manage a limited subset at flow level. The managed flows are usually of higher
rates than fair share. Following the heavy-tailed Internet flow distribution; these flows are indeed the minority in the
Internet. Using extensive simulations, we show that the scheme is highly fair and potentially scalable unlike other
proposed schemes.
4. ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Vol. 2, Issue 1, pp: (230-235), Month: April 2015 – September 2015, Available at: www.paperpublications.org
Page | 233
Paper Publications
Designing core-stateless versions of fair PFFQ is not an easy task. The main hurdle is that computation of flow parameters
is dependent on other interacting flows and it is impossible to determine these parameters at network edges. The goal of
AFpFT is to approximate the fairness of per flow fair queuing algorithms with minimum states possible.
There are two distinct but complementary ways to enforce flow fairness and protection in the Internet. The end-to-end
architectural design principle of the Internet, the more classical way has been via congestion control algorithms .These
algorithms are typically implemented in the transport protocols (e.g., TCP) of end-hosts. To ensure global fairness, such
schemes require all users to adopt them and respond to network congestion properly. This requirement can hardly be met
for at least two reasons. First, there is no performance incentive to end-users. This is because users who lack the
congestion control algorithms, intentionally or otherwise, may end up with a lion share of bandwidth. Second, in order to
meet real-time requirements, many applications do not implement congestion control. Hence, to protect responsive (e.g.,
TCP) flows from unresponsive (e.g., UDP) ones.
CHOKe is a simple and stateless active queue management (AQM) scheme. A highly attractive property of CHOKe is
that it can protect responsive TCP flows from unresponsive UDP flows. Choke is able to bound both bandwidth share and
buffer share a possible aggregate of UDP Traffic flow on a link.
When packets arrives at a congested router. CHOKe draws a packet at a random from the FIFO buffer and compares it
with the arriving packet. If both belong to same flow, then they are both dropped; else randomly chosen packet is left
intact and arriving packet is admitted into the buffer with a probability that depend on the level of congestion.
Fig 1 data flow diagram
7. CONCLUSION
This paper provides the first study on CHOKe behavior in the aftermath of rate changes in UDP traffic arrival. In
particular, we are concerned with CHOKe queue behaviors during the transient regime, which we model as a transition
from one steady queue state to another. We found that the performance limits stipulated in the steady state rarely hold for
such transient regimes. Depending on the nature of rate change, the queue exhibits instant fluctuations of UDP bandwidth
sharing in reverse direction. This behavior has ramifications on the smooth operation of the Internet where most flows are
rate-adaptive. Such flows may see fluctuating available link bandwidth and degrade in performance. By extending and
5. ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Vol. 2, Issue 1, pp: (230-235), Month: April 2015 – September 2015, Available at: www.paperpublications.org
Page | 234
Paper Publications
leveraging the spatial distribution model, this paper analytically: 1) determines the extreme points of UDP utilization
(observed within an order of queuing delay after rate change); and 2) tracks the evolution of the transient UDP utilization
following rate change. In addition, the model allows us to obtain generic UDP utilization plots that help explain both the
transient extreme characteristics and steady-state characteristics. The analytic results have been rigorously validated
through extensive simulations. We believe the analytical approach used in this paper also sheds light on studying transient
behaviors of other leaky queues.
The analysis is independent of the specific flavor of TCP window control algorithm. The only condition placed upon TCP
flows is that they collectively are able to grab the remaining bandwidth left by the UDP flow. This can easily be fulfilled
by most TCP algorithms, making the analysis and results applicable to a wide variety of TCP algorithms. Recall from the
analysis that the transient behavior is mainly controlled by the UDP source rate and factor of rate change. Therefore, it is
plausible to formulate the analysis on a rate-based model, rather than window-based. The latter is commonly used for
investigating (microscopic) TCP behavior. The TCP flows are of secondary importance as they merely take up the
bandwidth left over by the UDP flow. As a result, detailed modeling of TCP window control algorithms seems orthogonal
to this work. However, window-based analysis may be suitable in other situations where the TCP itself is the primary
control (or parameter of interest) or where the network behavior is controlled by multiple parameters.
AKNOWLEDEMENT
I am heartily grateful to my Head of the Department Mr. K.N SIVAKUMAR M.E., Associate Professor of Computer
Science and Engineering, for his constructive suggestions and support.With immense pleasure I regard my deep sense of
indebtedness and gratitude to the Mrs. S.DEVISRI, M.E., Assistant Professor of Department of Computer Science and
Engineering, who gave her guidance and support throughout my work and made this as a successful project.
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Page | 235
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