Analysis of TCP performance over mobile ad hoc networks

Holland, Gavin; Vaidya, Nitin H.

doi:10.1145/313451.313540

Cited by 604 publications

(504 citation statements)

References 9 publications

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“…Most of these techniques address mobility, link breakages and routing algorithm failures. Schemes such as ELFN [9], TCP-F [4], Fixed-RTO [5], and TCP-DOOR [22] belong to this category. Together, this work gives reasonable understanding on mobility related TCP inefficiencies.…”

Section: Related Workmentioning

confidence: 99%

“…First, as the topology changes, the path is interrupted and TCP goes into repeated, exponentially increasing time-outs with severe performance impact. Efficient retransmission strategies have been proposed to overcome such problems [4,5,9]. The second problem has to do with the fact that TCP performance in ad hoc multihop environment depends critically on the congestion window in use.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing TCP fairness in ad hoc wireless networks using neighborhood RED

Gerla

et al. 2003

Proceedings of the 9th Annual International Conference on Mobile Computing and Networking

161

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Significant TCP unfairness in ad hoc wireless networks has been reported during the past several years. This unfairness results from the nature of the shared wireless medium and location dependency. If we view a node and its interfering nodes to form a "neighborhood", the aggregate of local queues at these nodes represents the distributed queue for this neighborhood. However, this queue is not a FIFO queue. Flows sharing the queue have different, dynamically changing priorities determined by the topology and traffic patterns. Thus, they get different feedback in terms of packet loss rate and packet delay when congestion occurs. In wired networks, the Randomly Early Detection (RED) scheme was found to improve TCP fairness. In this paper, we show that the RED scheme does not work when running on individual queues in wireless nodes. We then propose a Neighborhood RED (NRED) scheme, which extends the RED concept to the distributed neighborhood queue. Simulation studies confirm that the NRED scheme can improve TCP unfairness substantially in ad hoc networks. Moreover, the NRED scheme acts at the network level, without MAC protocol modifications. This considerably simplifies its deployment.

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Section: Related Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhancing TCP fairness in ad hoc wireless networks using neighborhood RED

Gerla

et al. 2003

Proceedings of the 9th Annual International Conference on Mobile Computing and Networking

161

View full text Add to dashboard Cite

show abstract

“…Another solution is to exploit routing layer feedback (eg, route broken/route repaired) to TCP. In [10,11], TCP's state is frozen when the sender receives the route failure signal from intermediate nodes. TCP exits the frozen state when route is re-established.…”

Section: Airborne Swarmsmentioning

confidence: 99%

TCP over Geo-routing for High Mobility: Vehicle Grids and Airborne Swarms

2006

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Summary. Ad hoc wireless networks have become the architecture of choice for peer to peer communications in areas where the telecommunications infrastructure is inadequate or has failed, A major challenge is the reliable delivery of data when nodes move. The reliable Internet protocol is TCP. However, TCP performs poorly in mobile ad hoc networks, mainly because of route breakage. To overcome this problem, a robust routing protocol must be used. To this effect, Geo-routing has recently received attention in large scale, mobile systems as it does not require endto-end path establishment and pre-computed packet forwarding routing structure at nodes. These properties make Geo-routing robust to highly dynamic route changes. For best performance, however, several parameters must be carefully tuned.In this paper we study the joint optimization of TCP and Geo-routing parameters to handle high speeds. We first introduce two highly mobile ad hoc scenarios that require reliable delivery, namely the vehicle urban grid and the airborne swarms. Then, we study the impact of critical system parameters (e.g., hello message exchange rate, delay timer in TCP for out-of-order delivery, etc) on the performance of both UDP and TCP. We improve hello message efficiency in Geo-routing by using an adaptive hello exchange scheme. Then, we fix the out-of-order problem in TCP by using a receiver-side out-of-order detection and delayed ack strategy. We show that these parameter adjustments are critical for efficient TCP over Geo-routing in highly mobile applications. With these enhancements our TCP with Geo-routing solution easily outperforms TCP over traditional ad hoc routing schemes, such as AODV.

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“…With the use of back-pressure, gradually, the rate at which the flows send the data to the node will also reduce. The effect travels backwards all the way to the source 8 . The source is then forced to adapt its rate to conform to the available bandwidth for the flow.…”

Section: Overviewmentioning

confidence: 99%

“…Most of the TCPbased proposals attempt to make TCP distinguish between packet losses due to mobility and congestion. To this effect, some researchers propose explicit link failure notifications (ELFN) [8] [7]. Significant work has been done at developing novel MAC layer schemes.…”

Section: Introductionmentioning

confidence: 99%

Improving the Performance of TCP in the Presence of Interacting UDP Flows in Ad Hoc Networks

Gupta

Krishnamurthy

Faloutsos

2004

Lecture Notes in Computer Science

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Abstract.In this paper, we study how fairness affects the performance of TCP over ad hoc networks with IEEE 802.11 at the MAC layer. The problem addressed is that the throughput of TCP flows degrades severely in the presence of heavily loaded UDP flows. Our contribution is twofold. First, we identify the factors affecting the TCP throughput by providing a micro-analysis of the performance at a level of detail that is not seen in previous studies. The intuition obtained from the first part leads us to our second contribution. We propose and study the use of per flow fairness through a mechanism we call backpressure. Backpressure improves the performance of TCP flows in the presence of heavy UDP flows. In fact, in some cases, this increased TCP throughput does not affect the throughput of UDP flows. We find that backpressure can increase the TCP throughput by as much as 95%. An advantage of backpressure is that it does not require any changes to the existing TCP or IEEE 802.11 protocols.

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Analysis of TCP performance over mobile ad hoc networks

Abstract: Mobile ad hoc networks

Cited by 604 publications

References 9 publications

Enhancing TCP fairness in ad hoc wireless networks using neighborhood RED

Enhancing TCP fairness in ad hoc wireless networks using neighborhood RED

TCP over Geo-routing for High Mobility: Vehicle Grids and Airborne Swarms

Improving the Performance of TCP in the Presence of Interacting UDP Flows in Ad Hoc Networks

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