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Hybrid Internet Access System Architecture
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DirecPC's Turbo Internet is a low-cost hybrid high-speed digital transmission system which uses receive-only satellite links for downstream data delivery and public telephone networks at modern speeds to provide the upstream communications path. One of the services provided is high-speed Internet access based on an asymmetric TCP/IP protocol. Our p...
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DirecPCT
M’s Turbo Internet is a low‐cost hybrid (satellite‐terrestrial) high‐speed digital transmission system developed as a collaborative effort between the Center for Satellite and Hybrid Communication Networks and Hughes Network Systems. The system uses receive‐only VSAT satellite links for downstream data delivery and public telephone network...
Citations
... For the star topology in figure 1.2, the forward channel bandwidth from the satellite to the earth terminals is much larger than the reverse channel bandwidth [8]. When the reverse channel traffic load is greater than the its bandwidth, congestion could happen. ...
... Third, congestion could happen in the reverse channel. The forward channel bandwidth from the satellite gateway to the ground terminals is much larger than the reverse channel bandwidth [8]. Most of the time, the users download data from the Internet and the reverse channel is used to transfer TCP ACKs. ...
... The lower plot shows the results for a larger message length range which is uniformly distributed from 7 to 11 slots. System throughput Average delay (ms) FMCSA Homogeneous (9) FMCSA Heterogeneous (8,9,10) MCSA Heterogeneous (8,9,10) System throughput Average delay (ms) FMCSA Homogeneous (9) FMCSA Heterogeneous (7,8,9,10,11) MCSA Heterogeneous (7,8,9,10,11) ...
Satellites are now being used to carry Internet traffic which brings new opportunities as well as new challenges to the satellite industry. Our goal in this dissertation is to design efficient and fair transport layer and medium access control layer protocols for satellite networks. Three problems have been addressed in this dissertation. The first problem is to improve TCP performance over satellite networks and a protocol called receiver window backpressure protocol (RWBP) is proposed to be used inside the satellite networks. RWBP has newly designed congestion control, error control and buffer management schemes. And it requires less reverse channel bandwidth without sacrificing the forward channel throughput. RWBP can still maintain good performance even when there is high priority traffic such as streaming video, audio competing with the TCP traffic in the satellite networks. The second problem is to investigate the transfer of short messages with delay constraints in the reverse channel. A multichannel random access protocol called FMCSA is proposed in this dissertation. FMCSA combines random access with packet level forward error correction (FEC) coding for new messages and scheduled
... In order to provide broadband Internet service for these customers, satellite hybrid network was proposed to solve this lastmile problem (figure 1). This kind of hybrid networks exploits three observations [1]: 1) some rural areas may not be reached by fiber networks or it may be too expensive to do so; 2) satellite hybrid networks can provide high bandwidth to a large geographical area and it is easy to deploy; 3) home users usually consume much more data than they generate. So this asymmetric hybrid network fits in the need very well. ...
... But when the window is large, it is more likely that multiple packets are lost in one window caused either by congestion or link layer corruptions or both. The multiple losses will trigger TCP congestion control algorithms and lead TCP to actually operate with 1 Maximum segment size Server Client SGW a small average window. For the same reason, the sender buffer size can also limit the TCP connection throughput if it is less than the bandwidth delay product, which is usually the case in a lot of operating systems. ...
... In hybrid architectures a spoo ng technique consists in isolating, in a transparent way, the satellite link from the rest of the network. TCP performance issues for this particular type of network topology are out of the scope of this paper, see 5,8,19] for a thorough study. An other approach consists in using non-TCP mechanisms which operate at a given layer of the OSI model. ...
Satellite communications are destined to play an important role in future telecommunications infrastructure. There is in particular
an increasing interest in transporting Internet traffic over satellite links. Many studies have shown that TCP has a poor
performance in the context of satellite communications. This is due to many factors inherent to satellite communications and
for which TCP – originally designed for terrestrial networks – is inadequate. Our study is an overview of the many factors
limiting TCP performance over a satellite link and the different solutions proposed to address the problem.
... There exists a proposal for a low-cost solution to deliver high bandwidth services over wide geographical areas via the use of broadcast satellite networks [8]. Since this solution is based on low cost receivers with zero bandwidth return, the connection over the satellite link is unidirectional. ...
New transmission media have been proposed to provide higher bandwidth to the Internet – satellite links offer unidirectional and asymmetric access. Both unidirectional and asymmetric links should be integrated into the Internet transparently. However, there are some specific problems that must be solved in the case of unidirectional links. The UniDirectional Link Routing working group [1] focuses on supporting unidirectional links on top of bi-directional internetwork. In order to support unidirectional links, there are two approaches: 1) modifications to common Internet routing protocols (RIP, OSPF etc.), or 2) a new layer between the network interface and the routing software to emulate bi-directional links through tunnels.
... Third, congestion could happen in the return channel. The forward channel bandwidth from the satellite gateway to the ground terminals is much larger than the return channel bandwidth [4]. Most of the time, the users download data from the Internet and the return channel is used to transfer TCP ACKs. ...
Satellite networks are going to play an impor-tant role in the global information infrastructure. Satellites can be used to provide Internet services to fixed users and to mobile users. However, recent measurements show that the satellite link efficiency is only about 30%. In order to improve the performance of Internet over satellite, a new protocol called Receiver Window Backpressure Pro-tocol (RWBP) is proposed. RWBP uses per-flow queuing, round robin scheduling and receiver window backpressure for congestion management. Simulation results show that RWBP can maintain high utilization of the satellite link and improve fairness among the competing connections.
