H. Balakrishnan, S. Seshan, E. Amir, R.H. Katz: "Improving TCP/IP Performance over Wireless Networks", Proceedings of Mobicom, November `95  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... di erences in both network characteristics (mainly higher error rates and connectivity disruptions) and end system characteristics (mainly constrained resources, frequently power economy requirements) Although one can nd several suggestions for such an infrastructure in recent literature (e.g. [5 8,10,11,19,38]) which all improve the quality of wireless Internet access, we think that an appropriate solution is still missing. From the application point of view Internet access means access to the services of the Internet protocol This work was partially supported by Deutsche Telekom Berkom in the ....

....to contribute to this ongoing discussion by de ning and implementing main elements of ReSoA. We demonstrate using measurements in real environment, that ReSoA provides better performance not only in comparison with the original, unmodi ed desktop approach but also in comparison with Berkeley Snoop [5] (which is acknowledged to be one of the most promising extensions of the desktop approach) while keeping the semantics unchanged as far as possible. It is not our goal to present a complete, detailed speci cation of ReSoA, but instead to de ne its essential elements needed for implementation ....

[Article contains additional citation context not shown here]

H. Balakrishnan, S. Seshan, E. Amir, R.H. Katz: "Improving TCP/IP Performance over Wireless Networks", Proceedings of Mobicom, November `95

....of TCP may skip this TCP for Wireless Networks 2 section without any loss of continuity. In Section 3, we have presented an overview of the splitconnection [6, 7, 8, 9, 11] approaches to solving the problem and have discussed their merits and drawbacks. Sections 4 and 5 talk about the TCP aware [12, 13, 14, 15] and TCP unaware [16] approaches respectively. Section 6 summarizes various Explicit Notification mechanisms [18, 5, 19] In Sections 7 and 8, we discuss generic approaches that distinguish between congestion losses and transmission losses by using two connections [20] and receiver based ....

....of the overlying TCP. 4.1. Snoop Protocol TCP for Wireless Networks 9 The primary motivation behind this protocol was to effectively use TCP for wireless links without sacrificing its end to end semantics and with minimum modifications to the existing TCP implementations. The snoop protocol [12, 13, 14] makes modifications only to the routing code at the base stations. The base station routing code is modified by the addition of a module, called the snoop agent. The agent monitors communication across the connection in either direction and caches packets that have not been acknowledged by the ....

[Article contains additional citation context not shown here]

H. Balakrishnan, S. Seshan, and R. Katz, "Improving TCP/IP performance over wireless networks," Proc. first ACM Mobicom, November 1995.

....conditions that we are addressing in this paper, networks with long delays and networks with highly volatile bandwidth, are two such examples. Moreover, PEP have been proven practical and effective for other link characteristics as well, such as the TCP snooping technique for lossy wireless links [11] and the protocol booster idea[12] Compared to snoop, our PEP does elaborate congestion control. One of our conjectures is that with our proxy, we can provide better QoS with better jitter and delay guarantees by fine tuning the watermark. In other words the watermark would become a function of ....

H. Balakrishnan, S. Seshan, E. Amir, and R. Katz, "Improving TCP/IP performance over wireless networks," ACM SIGCOMM'96, Aug. 1996.

....in [MJP95] and [PJ96] Mobile IP allows transparent routing of IP packets to mobile nodes through the caching of care of address associated with a mobile node s home address. Several reliable transport layer protocols for networks with wireless links have been proposed. The Snoop protocol in [BSAK95] caches packets at the base station and performs local retransmissions across the wireless link. The network layer software at a base station is modified to preserve end to end TCP semantics. In contrast, the Indirect TCP (I TCP) protocol [BB94, BB95] splits a TCP connection at the base station, ....

....mote is out of range of its registered home base station, it registers with the nearby foreign base station. A tunnel will be set up between the home base station to the foreign base station to forward all the traffic. Split connection approach. The split connection approach similar to I TCP [B94, BB95, BSAK95] is taken for design simplicity. Acknowledgments received by the applications or remote motes are not end to end. Due to the limited storage space and processing power on the motes, it is impossible to place a full blown TCP IP stack on it. Thus, our design places with a proxy base station in ....

Hari Balakrishnan, Srinivasan Seshan, Elan Amir, Randy H. Katz, "Improving TCP/IP Performance over Wireless Networks", Proceedings of MobiCom95, November 1995.

....on a path. Allman and Paxson in [14] report and compare techniques for probing the available bandwidth in order to properly initialize the ssthresh before a TCP connection is started. An excessively large ssthresh can lead to premature timeout, slow start and efficiency loss. Lai and Baker in [15] describe an improved measurement technique (packet tailgating) to probe available bandwidth that is less intrusive (ie, consumes less bandwidth) than previous techniques. The above techniques share with our scheme the notion of measuring the interpacket delay gaps and deriving bandwidth ....

H. Balakrishnan, S. Seshan, E. Amir, and R. H. Katz, "Improving TCP/IP Performance Over Wireless Networks," MOBICOM'95, Berkeley, CA, USA, November 1995

....links has been extensively studied for the past few years. Proposed performance enhancing techniques can roughly be categorized into link layer solutions (see for example [1] 2] end to end solutions where the end to end semantic of TCP is maintained (see for example [3] 4] 5] 6] 7] [8], 9] 10] and non end to end solutions where the end to end semantic is violated (see for example [11] 12] 13] Various link layer and end to end approaches can be quite effective for connections over wireless links through improved error correction, local retransmission and distinguishing ....

H. Balakrishnan, S. Seshan, E. Amir, and R. H. Katz, "Improving TCP/IP Performance Over Wireless Networks," ACM/IEEE International Conference on Mobile Computing and Networking (MobiCom'95), vol. 2, no. 11, 1995.

....a wireless network employs time varying channels where packet losses may be common due to severe fading. This is misinterpreted by TCP as congestion which leads to inefficient utilization of the available radio link capacity. The result is significant degradation of the wireless system performance [1 3]. Exploiting efficient algorithms at lower layers of wireless networks such as retransmission protocols (ARQ) adaptive error correction, and adaptive modulation combined with channel prediction can significantly improve the communication reliability and throughput. In this way, the lower layers ....

H. Balakrishnan, S. Seshan, E. Amir, and R.H. Katz, "Improv- ing TCP/IP performance over wireless networks," in Proc. MOBICOM, Berkeley, CA, 1995, pp. 2--11.

....Accordingly, all previous schemes decrease transmission rate when packet losses are detected. However, some links, such as wireless and satellite links, are characterized by high link error rates and thus, packet losses can occur due to link errors with probability even higher than 10 Gamma2 [3], 1] If the source decreases its transmission rate when a packet loss occurs due to link errors, then network efficiency decreases drastically [17] 21] i.e. it can be lower than 20 . This problem is amplified by the long delays involved in most Internet communications. For example, in Table ....

H. Balakrishnan, S. Seshan, E. Amir and R. H. Katz, "Improving TCP/IP Performance over Wireless Networks," in Proc. of ACM Mobicomm'95, November 1995.

....not true for wireless media where, due to fading channels and user mobility, transmission losses are more frequent. Since certain assumptions behind TCP s highly tuned algorithms do not hold for transmission heterogeneous media, current TCP implementations do not perform well in such environments [12 15]. In addition to random errors and hand offs, TCP must also cope with connections that, in certain cases, exhibit limited bandwidth and large round trip times (RTTs) Moreover, for mobile battery operated devices, power consumption is an important issue that is not addressed by current versions of ....

....TCP s in order to avoid this duplicated effort. Moreover, the LL protocol should try to avoid triggering fast retransmit at the TCP sender, for example by not delivering incoming frames out of order. TCP Aware LL Protocols The most prominent proposal in this category is the snoop protocol [12]. Snoop was designed so that the wired infrastructure of the network would need no changes. A snoop agent must, however, reside at the base station (BS) while the mobile host would need to run the snoop protocol. The BS snoop agent inspects every TCP segment that is sent to or received from the ....

H. Balakrishnan et al., "Improving TCP/IP Performance Over Wireless Networks," Proc. ACM MobiCom, Nov. 1995.

....for wireless networks where the time varying channel experiences severe fading. Therefore, TCP misinterprets the packet losses over the wireless radio link as congestion which leads to inefficient utilization of the available radio link capacity and therefore degradation of the system performance [1 3]. Exploiting the facilities provided at lower layers of wireless networks such as hybrid FEC ARQ and adaptive modulation can improve the communication reliability. In this way, the major part of error recovery is performed at lower layers without being noticed at higher layers. Moreover, the ....

Hari Balakrishnan, Srinivasan Seshan, Elan Amir, and Randy H. Katz, "Improving TCP/IP Performance over Wireless Networks," in Proc. MOBICOM, Berkeley, CA, 1995, pp. 2--11.

....there is a clear distinction between the wired part and the wireless part of the path. In such cases, TCP improvements involve caching on the base station and locally retransmitting lost packets by either splitting the TCP connection [3, 11] or employing some specialized link layer protocol [5, 6, 7, 30]. 3 Finally, numerous end to end solutions have been proposed using more sophisticated acknowledgment techniques [13] probing mechanisms to detect network conditions [31, 32] and feedback from the wireless network adapter on the receiver [16] 1.2 The AIMD principle As mentioned earlier, the ....

H. Balakrishnan, S. Seshan, E. Amir, and R. Katz, "Improving TCP/IP Performance over Wireless Networks," in Proceedings of the 1st ACM Int'l Conf. On Mobile Computing and Networking (Mobicom), November 1995.

....true for wireless media where, due to fading channels and user mobility, transmission losses are more frequent. Since certain assumptions behind TCP s highly tuned algorithms do not hold for such transmission heterogeneous media, current TCP implementations do not perform well in such environments [8][16] 22] 77] In addition to random errors and hand offs, TCP must also cope with connections that, in certain cases, 2 exhibit limited bandwidth and large RTTs. Moreover, for mobile battery operated devices, power consumption is an important issue which is not addressed by current TCP versions. ....

....TCP s in order to avoid this duplicated effort. Moreover, the LL protocol should try to avoid triggering Fast Retransmit at the TCP sender, for example by not delivering incoming frames out of order. 2.1. 1 TCP aware LL protocols The most prominent proposal in this category is the snoop protocol [8]. Snoop was designed so that the wired infrastructure of the network would need no changes. A snoop agent must, however, reside at the base station (BS) while the mobile host would need to run the snoop protocol. The BS snoop agent inspects every TCP segment that is sent to or received from the ....

H. Balakrishnan, S. Seshan, E. Amir, and R. Katz. "Improving TCP/IP Performance Over Wireless Networks". In Proceedings of ACM MobiCom, November 1995.

....of the intermediate node (containing TCP state machines in the radio access network) become irrecoverable; It introduces extra overhead when moving TCP states between the intermediate nodes at handoff between radio access points. Figure 1: Split connections Snoop protocol The snoop protocol [7] introduces a module, called the snoop agent, at the base station. The agent monitors every packet that passes through the TCP connection in both directions and maintains a cache of the TCP segments sent across the link that have not yet been acknowledged by the receiver. A packet loss is detected ....

H. Balakrishnan, S. Seshan, E. Amir, R. H. Katz, "Improving TCP/IP performance over wireless networks", Proc. ACM MobiCom'95, pp.2-11, 1995.

.... which exhibit characteristics different from wired ones, e.g. random segment corruption over wireless links (Lee, 1993; Tabbane, 2000) Different improvement proposals attempt to alleviate TCP s inefficiencies in a wired cum wireless environment (Allman et al. 2000; Bakre Badrinath, 1995; Balakrishnan et al. 1995; Cceres Iftode, 1995; Parsa Garcia Luna Aceves, 1999; Sinha et al. 1999) Testing the comparative efficiency of these proposals requires realistic error models (Zorzi Rao, 1999; Pentikousis, 2000) 2 TEMPORAL VS. RATE BASED ERROR MODELS This work investigates the impact that two broad ....

Balakrishnan, H., Seshan, S., Amir, E., & Katz, R. (1995). "Improving TCP/IP Performance over Wireless Networks". In Proceedings of ACM MobiCom, November 1995.

....that does not have enough queue space for these segments or when there is a slower link between the sender and the receiver [9] It has been shown [5] that this approach can seriously reduce the throughput of a TCP connection. 1 Situations where this assumption may not hold are discussed in [6, 7, 8]. 1.1 Congestion Control Avoidance 4 TCP uses the slow start algorithm to avoid the problems discussed above. Slow start adheres to the conservation of packets notion that was mentioned previously. In addition to the window advertised by the receiver (rwnd) slow start uses an additional window ....

H. Balakrishnan, S. Seshan, E. Amir, and R. H. Katz, "Improving tcp/ip performance over wireless networks," In proc. 1st ACM Int'l Conf. on Mobile Computing and Networking (Mobicom), p. 10, November 1995.

....down its transmission rate because the network has reached its capacity. This interpretation is mostly true for wired only networks. Unfortunately, if we also have wireless links in a communication path this could be wrong. Hence TCP makes a wrong assumption, which usually leads to bad performance [5, 6, 9, 29]. Since we would like TCP to work well in wired cum wireless environments it is necessary that we find a strategy that decides in an intelligent manner what is happening, i.e. makes the right guess every time. In other words, TCP must work well under all underlying heterogeneous or homogeneous ....

....delivery of packets at all times, for example using an Automatic Repeat reQuest (ARQ) scheme. However, studies have shown that this could lead to degraded performance [9] This is because TCP also attempts to ensure reliable transmission, thus leading to a lot of duplicated effort. The authors in [6] suggest that if such a solution were accepted, it has to be tightly coupled with TCP. Nevertheless, the developers of TULIP (Transport Unaware Link Improvement Protocol) show that over half duplex radio channels an uncoupled solution is indeed possible, and can yield better performance [22] ....

[Article contains additional citation context not shown here]

H. Balakrishnan, S. Seshan, E. Amir, and R. Katz. "Improving TCP/IP Performance Over Wireless Networks". In Proceedings of ACM MobiCom, November 1995.

....true for wireless media where, due to fading channels and user mobility, transmission losses are more frequent. Since certain assumptions behind TCP s highly tuned algorithms do not hold for such transmission heterogeneous media, current TCP implementations do not perform well in such environments [8][15] 19] 63] In addition to random errors and hand offs, TCP must also cope with connections that, in certain cases, exhibit limited 2 bandwidth and large RTTs. Moreover, for mobile battery operated devices, power consumption is an important issue which is not addressed by current TCP versions. ....

....TCP s in order to avoid this duplicated effort. Moreover, the LL protocol should try to avoid triggering Fast Retransmit at the TCP sender, for example by not delivering incoming frames out of order. 2.1. 1 TCP aware LL protocols The most prominent proposal in this category is the snoop protocol [8]. Snoop was designed so that the wired infrastructure of the network would need no changes. A snoop agent must, however, reside at the base station (BS) while the mobile host would need to run the snoop protocol. The BS snoop agent inspects every TCP segment that is sent to or received from the ....

H. Balakrishnan, S. Seshan, E. Amir, and R. Katz. "Improving TCP/IP Performance Over Wireless Networks". In Proceedings of ACM MobiCom, November 1995.

....the host to improve end to end performance with a wireless link at the end point, setting packet length on a session by session basis according to current channel conditions. This is an evolution of recent work on improving performance of TCP over wireless links by a number of researchers such as [Balakrishnan95] where a TCP aware snoop agent in the base station monitors traffic and intervenes with local retransmissions to the remote host when error related packet losses are experienced. Perhaps closest to the current paper in scope, Hara96] presented a simulation based study of throughput improvements ....

H. Balakrishnan, S. Seshan, E. Amir, R.H. Katz, "Improving TCP/IP Performance over Wireless Networks, " In Proceedings of the First ACM Conference on Mobile Computing and Networking 1995 (MobiCom'95), November 1995.

....and adaptation manager) that best assists multimedia applications when adapting to minor QOS fluctuations as a consequence of cell packet loss and delay variation; and . active mode, which provides a set of ATOs (viz. mobile filters [2] mobile error control [12] modules and mobile snoop [3] modules) that can be dynamically dispatched to mobile devices, base stations or mobile capable ATM switches to provide value added QOS during conditions of persistent QOS fluctuation that may emerge during handoff. 70 QOS AWARE MIDDLEWARE FOR MOBILE MULTIMEDIA COMMUNICATIONS 75 Figure 4. ....

....control modules, which provide hybrid ARQ and FEC mechanisms for improved reliability of audio, video and data over the air interface during periods of excessive cell frame loss [12] and . mobile snooping modules, which help increase the performance of flows (e.g. TCP data flows) by snooping [3, 12] end to end protocol messages as a means to trigger the local value added error control mechanism over the air interface. ATO are application specific and interact with differing algorithms to provide value added support. For example, mobile filters are driven by an available bandwidth indication ....

S. Balakrishnan, E. Amir Seshan, and R.H. Katz, "Improving TCP/IP performance over wireless networks," 1st International Mobile Computing and Networking (MOBICOM'95), Berkeley, Nov. 1995.

No context found.

H. Balakrishnan, V. Padmanabhan, S. Seshan, R.H. Katz: "Improving TCP/IP Performance over Wireless Networks", Proc. 1st ACM Conf. on Mobile Computing and Networking, Berkeley, CA, November 1995

No context found.

) Hari Balakrishnan, Srinivasan Seshan, Elan Amir, and Randy H. Katz, "Improving TCP/IP Performance over Wireless Networks", Proc. 1st ACM Conf. on Mobile Computing and Networking, Berkeley, CA, November 1995.

No context found.

H. Balakrishnan, S. Seshan, E. Amir, and R. H. Katz, "Improving TCP/IP performance over wireless networks," 1 st Intl. Conf. on Mobile Computing and Networking, November 1995.

No context found.

H. Balakrishnan, S. Seshan, E. Amir, and R. Katz. "Improving TCP/IP Performance Over Wireless Networks". In Proceedings of ACM MobiCom, November 1995.

No context found.

H. Balakrishnan, S. Seshan, E. Amir, and R. H. Katz, "Improving TCP/IP performance over wireless networks," 1 st Intl. Conf. on Mobile Computing and Networking, November 1995.

No context found.

Hari Balakrishnan, Srinivasan Seshan, Elan Amir, and Randy Katz, "Improving TCP/IP Performance Over Wireless Networks," Mobicom 95, Nov. 1995

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC