Am I missing a thread? Or is this the correct/not correct place to discuss the Rural Digital Opportunity Fund (RDOF) subsidy denial for Starlink?
DARPA Kicks Off Program to Develop Low-Earth Orbit Satellite ‘Translator’Teams begin work on novel optical intersatellite communications terminal to connect satellite networks[email protected]8/10/2022DARPA has selected 11 teams for Phase 1 of the Space-Based Adaptive Communications Node program, known as Space-BACN. Space-BACN aims to create a low-cost, reconfigurable optical communications terminal that adapts to most optical intersatellite link standards, translating between diverse satellite constellations. Space-BACN would create an “internet” of low-Earth orbit (LEO) satellites, enabling seamless communication between military/government and commercial/civil satellite constellations that currently are unable to talk with each other.The agency selected teams from academia and large and small commercial companies, including multiple performers awarded first-time contracts with the Department of Defense.“We intentionally made making a proposal to our Space-BACN solicitations as easy as possible, because we wanted to tap into both established defense companies and the large pool of innovative small tech companies, many of which don’t have the time or resources to figure out complicated government contracting processes,” said Greg Kuperman, Space-BACN program manager in DARPA’s Strategic Technology Office. “We used other transactions and were very pleased with diversity of organizations that responded and quality of proposals. After a successful Phase 0 where we got to see the teams sprint to put together an initial architecture design for Space-BACN, I'm excited to get to work in Phase 1 building the actual system.”In the first technical area, the following performers aim to develop a flexible, low size, weight, power and cost (SWaP-C) optical aperture that couples into single-mode fiber:* CACI, Inc.* MBRYONICS* MynaricThe following teams selected in the second technical area aim to develop a reconfigurable optical modem that supports up to 100 Gbps on a single wavelength:* II-VI Aerospace and Defense* Arizona State University* Intel Federal, LLCThe performer teams listed above will also participate in a collaborative working group to define the interface between their respective system components.In a third technical area, the agency selected five teams to identify critical command and control elements required to support cross-constellation optical intersatellite link communications and develop the schema necessary to interface between Space-BACN and commercial partner constellations:* Space Exploration Technologies (SpaceX)* Telesat* SpaceLink* Viasat* Kuiper Government Solutions (KGS) LLC, an Amazon subsidiaryPhase 1 of Space- BACN spans 14 months and will conclude with a preliminary design review for the first two technical areas, as well as a fully defined interface between system components. The third technical area will develop the schema for cross-constellation command and control, and will conduct a connectivity demo in a simulated environment to test the schema for a baseline scenario.At the completion of Phase 1, selected performers in the first two technical areas will participate in an 18-month Phase 2 to develop engineering design units of the optical terminal components, while performers in the third technical area will continue to evolve the schema to function in more challenging and dynamic scenarios.
Think about the feasibility of an in-space common Internet backbone backhaul that different constellations can purchase connections and data transport through. Possibly making a large LEO interconnected Internet backbone that covers the globe. This could be in the long run a big positive due to not having a lot of data traffic to not get transported back and forth from space and Earth surface by going through an internet switching node on-orbit between in-orbit ISPs. By eliminating a single up-down bounce to the point to point data traffic you can greatly increase the effectiveness of the offered up-down troughput.
Quote from: oldAtlas_Eguy on 08/23/2022 05:55 pmThink about the feasibility of an in-space common Internet backbone backhaul that different constellations can purchase connections and data transport through. Possibly making a large LEO interconnected Internet backbone that covers the globe. This could be in the long run a big positive due to not having a lot of data traffic to not get transported back and forth from space and Earth surface by going through an internet switching node on-orbit between in-orbit ISPs. By eliminating a single up-down bounce to the point to point data traffic you can greatly increase the effectiveness of the offered up-down troughput.You just need interconnects, not a separate core backbone net. Easier and more efficient. The sending net would forward to the receiving net at the earliest (i.e., shortest-path) opportunity because the sending net does not know the geolocation of the receiving user. The receiving net then does optimal routing based on its algorithms. Otherwise, you would need to exchange an unacceptably large amount of info about the current dynamic topology of each network. Back in the day, we used to do this in the core internet in locations known as IXPs, and I suspect we still do, although Peer-to-peer is now more prevalent. It seems to be selfish and greedy (get this traffic off of my net as quickly and cheaply as possible) but it is in fact more efficient. To implement this maybe use a small constellation of IXP satellites that each are members of all participating networks. These satellites don't in general need to talk directly to each other.
The idea that terrestrial Internet routing is a fixed route is a falsehood. The route can change multiple times during the interchange between the connected actors. This is one of the factors in why the round trip can time can change during the connection. It's dynamic. Just not as dynamic as what is being proposed for an in-orbit Internet Node functionality.
I don't see much use for a generic on-orbit backbone. In almost all cases, terrestrial backbones have orders of magnitude more bandwidth, and the topology is soooooo much simpler. However, I can think of a few special-purpose cases where a small backbone might make sense:
Your service area remains at capacity which means we are unable to convert you to Residential service at this time. Our best estimate for delivery of Residential service in your area is now mid-2023. Adding users before adding additional network capacity would result in delivery of a lesser service. However, we understand that some customers may have urgent connectivity needs with no other alternatives. For those with urgent connectivity needs, we are offering a Best Effort service option. What is Best Effort?Best Effort enables typical internet activity with the understanding that Best Effort users will be deprioritized behind Residential users. The monthly service charge is the same but unlike Residential, Best Effort users will have the option to pause service on their account page. What will the internet experience be like with Best Effort?During times of peak network congestion, Best Effort users will experience notably slower speeds than Residential users. Best Effort users will be able to engage in typical internet activity like email, online shopping, or streaming an SD movie, but they won’t be able to engage in activities like online gaming, video calls or streaming 4K and HD movies. Outside times of peak network congestion, Best Effort users can expect to engage in all of the above activities and more, but speeds will be slower than Residential users. If I choose Best Effort now, do I lose my place in line for Residential service?No, if you choose Best Effort you will not lose your spot in line. When capacity increases in your area, your service will be upgraded automatically at no additional cost. You can opt-in to Best Effort from your account page at any time or by clicking the button below. OPT-IN TO BEST EFFORTBest Effort is intended for pre-order customers with urgent connectivity needs. If you can wait for Residential, we strongly encourage you to do so. In just 18 months, our teams have already enabled over 600,000 users across 40 markets. By mid-2023, our rapid launch rate and higher performing satellites, coupled with the continuous deployment of software features to optimize our network, will enable a high quality connection for millions more across the globe. As always, you cancel your pre-order at any time on your account page for a full refund of your deposit. We appreciate your continued patience and we look forward to getting you online! The Starlink Team
So, ah, just got this:QuoteYour service area remains at capacity which means we are unable to convert you to Residential service at this time. Our best estimate for delivery of Residential service in your area is now mid-2023. Adding users before adding additional network capacity would result in delivery of a lesser service. However, we understand that some customers may have urgent connectivity needs with no other alternatives. For those with urgent connectivity needs, we are offering a Best Effort service option. What is Best Effort?Best Effort enables typical internet activity with the understanding that Best Effort users will be deprioritized behind Residential users. The monthly service charge is the same but unlike Residential, Best Effort users will have the option to pause service on their account page. What will the internet experience be like with Best Effort?During times of peak network congestion, Best Effort users will experience notably slower speeds than Residential users. Best Effort users will be able to engage in typical internet activity like email, online shopping, or streaming an SD movie, but they won’t be able to engage in activities like online gaming, video calls or streaming 4K and HD movies. Outside times of peak network congestion, Best Effort users can expect to engage in all of the above activities and more, but speeds will be slower than Residential users. If I choose Best Effort now, do I lose my place in line for Residential service?No, if you choose Best Effort you will not lose your spot in line. When capacity increases in your area, your service will be upgraded automatically at no additional cost. You can opt-in to Best Effort from your account page at any time or by clicking the button below. OPT-IN TO BEST EFFORTBest Effort is intended for pre-order customers with urgent connectivity needs. If you can wait for Residential, we strongly encourage you to do so. In just 18 months, our teams have already enabled over 600,000 users across 40 markets. By mid-2023, our rapid launch rate and higher performing satellites, coupled with the continuous deployment of software features to optimize our network, will enable a high quality connection for millions more across the globe. As always, you cancel your pre-order at any time on your account page for a full refund of your deposit. We appreciate your continued patience and we look forward to getting you online! The Starlink Team Must be nice to be so in demand that you can beg your customers not to buy...
Optical ISL has the potential to change this completely. (Whether or not is actually happens, and when, is another story.) If access to space is cheap you can use large satellites with lots of power for lasers and optical amplifiers. A single ISL in free space can carry a very large number of lambdas, not just the optical C-band and S-band of a fiber link. Speed of light in free space is 300,000 km/s, while speed of light in fiber is about 200,000 km/s. More importantly, ISL links are straight lines, not following fiber rights-of-way. It will ultimately be cheaper to use ISL than long-haul fiber, and this will be true from the beginning for any data that can avoid an extra uplink and downlink. You don't necessarily need a separate shared ISL backbone. You do need to interface each constellation's backbones to each other.
Quote from: DanClemmensen on 08/23/2022 10:24 pmOptical ISL has the potential to change this completely. (Whether or not is actually happens, and when, is another story.) If access to space is cheap you can use large satellites with lots of power for lasers and optical amplifiers. A single ISL in free space can carry a very large number of lambdas, not just the optical C-band and S-band of a fiber link. Speed of light in free space is 300,000 km/s, while speed of light in fiber is about 200,000 km/s. More importantly, ISL links are straight lines, not following fiber rights-of-way. It will ultimately be cheaper to use ISL than long-haul fiber, and this will be true from the beginning for any data that can avoid an extra uplink and downlink. You don't necessarily need a separate shared ISL backbone. You do need to interface each constellation's backbones to each other.Don't confuse bandwidth and propagation speed. They're not completely unrelated, but multimode fiber has vastly less dispersion and more chances to re-amplify the signal.In theory, you can have a lot more links in an n-to-n mesh with satellites, but it's a horrid routing problem to keep things from flapping, and of course you can plunk down as many fibers as you like in a fiber bundle.You might be right one day in the future, but I don't think we're talking in the Gen2 timeframe. And I doubt that the ISL cost per bps will ever exceed that of fiber.
Sorry, no. A long-haul fiber needs optical amplifiers, usually EDFAs, at intervals of perhaps 150 km. An ISL link in vacuum using a 10 CM telescope can go at least 1000 km if you use enough power. Long-haul fiber is single mode, not multi mode. A single fiber carries multiple "lambdas", each of which carries one digital channel, using DWDM. A fiber almost always operates in only one optical band, and for long haul this is the optical C band. In 2000 a fiber carried 160 lambdas at a spacing that allowed 10 Gbit/s per lambda, for 1600 Gbit/s per fiber. The C band, centered on about 1550 nm, is in the transparency sweet spot for the long-haul fiber, where the sum of scattering loss and absorption loss is lowest. We now use higher bit rates but on more widely-spaced lambas resulting in maybe 3200 Gbit/sec per fiber. Of course, a cable has lots of separate fibers. By contrast, we do not have absorption loss or scattering in free space, so we can use all wavelengths. Our losses occur due to dispersion, which depends on distance. We can use lasers from Moon to earth, but dispersion is so high that the signal is weak. but this effect is obviously much smaller at distances in LEO. We will eventually be able to use all optical freqencies: thousands of times more lambdas than a single fiber, but only by using sufficient power.
Routing is an entirely separate problem. I prefer not to call it routing in the ISL network because except at the IXPs the frames will be forwarded at the frame level, not the packet level, using a highly specialized frame forwarding scheme. The topology changes radically and continuously, but in a completely predictable way, so the problem is very different than either fixed networks or cell networks and any attempt to reason by analogy will fail.
My uninformed speculation is that T-mobile will start rolling out terrestrial 5G/LTE cellular infrastructure in remote locations using Starlink backhaul instead of terrestrial backhaul.
This is something special
You can do wayyy more than 3.2Tbps now with DWDM -- modern line systems use C+L band and are capable of well over 32Tbps. The Ciena WaveServer does 12.8Tbps in 2RU. New submarine cables are doing >20Tbps per fiber pair.
