Internet over direct broadcast satellites

Clausen, H.D.; Linder, Hilmar; Collini-Nocker, Bernhard

doi:10.1109/35.769289

Cited by 37 publications

(18 citation statements)

References 2 publications

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“…-IP service over a forward satellite link utilizing Digital Video Broadcast (DVB) transmission [EN97] (e.g., 38-45 Mbps), and a slower upstream link using terrestrial network technology (e.g., dial-up modem, line of sight microwave, cellular radio) [CLC99]. Network path asymmetry arises from a difference in the upstream and downstream link capacities.…”

Section: Appendix -Examples Of Subnetwork Exhibiting Network Path Asmentioning

confidence: 99%

TCP Performance Implications of Network Path Asymmetry

Balakrishnan¹,

Padmanabhan²,

Fairhurst³

et al. 2002

100

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This document describes TCP performance problems that arise because of asymmetric effects. These problems arise in several access networks, including bandwidth-asymmetric networks and packet radio subnetworks, for different underlying reasons. However, the end result on TCP performance is the same in both cases: performance often degrades significantly because of imperfection and variability in the ACK feedback from the receiver to the sender.The document details several mitigations to these effects, which have either been proposed or evaluated in the literature, or are currently deployed in networks. These solutions use a combination of local link-layer techniques, subnetwork, and end-to-end mechanisms, consisting of: (i) techniques to manage the channel used for the upstream bottleneck link carrying the ACKs, typically using header compression or reducing the frequency of TCP ACKs, (ii) techniques to handle this reduced ACK frequency to retain the TCP sender's acknowledgment-triggered self-clocking and (iii) techniques to schedule the data and ACK packets in the reverse direction to improve performance in the presence of two-way traffic. Each technique is described, together with known issues, and recommendations for use. A summary of the recommendations is provided at the end of the document. , and several packet radio networks. These networks are increasingly being deployed as high-speed Internet access networks, and it is therefore highly desirable to achieve good TCP performance. However, the asymmetry of the network paths often makes this challenging. Examples of some networks that exhibit asymmetry are provided in the Appendix.Asymmetry may manifest itself as a difference in transmit and receive capacity, an imbalance in the packet loss rate, or differences between the transmit and receive paths [RFC3077]. For example, when capacity is asymmetric, such that there is reduced capacity on reverse path used by TCP ACKs, slow or infrequent ACK feedback degrades TCP performance in the forward direction. Similarly, asymmetry in the underlying Medium Access Control (MAC) and Physical (PHY) protocols could make it expensive to transmit TCP ACKs (disproportionately to their size), even when capacity is symmetric. Asymmetry due to Differences in Transmit and Receive CapacityNetwork paths may be asymmetric because the upstream and downstream links operate at different rates and/or are implemented using different technologies. In networks employing centralized multiple access control, asymmetry may be a fundamental consequence of the hub-and-spokes architecture of the network (i.e., a single base node communicating with multiple downstream nodes). The central node often incurs less transmission overhead and does not incur latency in scheduling its own downstream transmissions. In contrast, upstream transmission is subject to additional overhead and latency (e.g., due to guard times between transmission bursts, and contention intervals). This can produce significant network path asymmetry.Upstream capacity ma...

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Section: Appendix -Examples Of Subnetwork Exhibiting Network Path Asmentioning

confidence: 99%

TCP Performance Implications of Network Path Asymmetry

Balakrishnan¹,

Padmanabhan²,

Fairhurst³

et al. 2002

100

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“…The total overhead for a transmission depends on the packet length distribution and the encapsulation method selected. The observed overhead for MPE is typically between 13% and 15% [2].…”

Section: Mpeg-2 and Ip Over Dvbmentioning

confidence: 99%

Efficient Support of IP Multicast in the Next Generation of GEO Satellites

Filali

Aniba

Dabbous

2004

IEEE J. Select. Areas Commun.

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Abstract-Satellites are expected to have an important role in providing the Internet protocol (IP) multicast service to complementing next-generation terrestrial networks.In this paper, we focus on the deployment of IP multicast over the next generation of digital video broadcasting-based geosynchronous earth orbit satellites supporting multiple spot beams and on-board switching technologies. We propose a new encapsulation scheme optimized for IP multicast, which has two distinct modes enabling two alternative on-board switching approaches: the selfswitching and the label-switching. We also detail a set of mechanisms and protocols for ground stations, as well as for the on-board processor to allow an efficient multicast forwarding in this type of environment, while reducing the load of control and data messages in the satellite segment, and building efficient multicast delivery trees reaching only the spot beams containing at least one member of the corresponding multicast session.To integrate satellite links in the terrestrial Internet, we present satellite multicast adaptation protocol (SMAP), a protocol which is implemented in satellite stations to process incoming protocol independent multicast-sparse mode (PIM-SM) messages sent by terrestrial nodes to the satellite system. SMAP helps to update the tables required for the mapping between IP packets and MPEG-2 data segments, their switching on board the satellite, and their filtering at the satellite receivers.Index Terms-Digital video broadcasting via satellite (DVB-S), DVB-return channel via satellite (RCS), Internet protocol (IP), multicast geosynchronous earth orbit (GEO) satellites, multiple spot beams, on-board switching, protocol independent multicastsparse mode (PIM-SM) protocol.

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“…The MPE specification includes a set of optional header components and requires decoding of the control headers. This processing is suboptimal for Internet traffic, since it incurs significant receiver processing overhead and some extra link overhead [CLC99].…”

Section: Encapsulation Protocol Requirementsmentioning

confidence: 99%