I C SPACE LIGHTS....

 ED. NOTE: I'd cut and pasted this from my own response, tonight, in an online forum.

Considering the OSI seven layer model: There may be some applications possible for existing fiber optic "layer 1" technologies, therein using  a sort of "different" optical media, though, namely in real "Outer space," moreover in a context of the emerging privatization of "Outer space," as around such as Richard Branson's Virgin Galactic and SpaceShip Two, the latter's "home spaceport" being located near Las Cruces, New Mexico.

Observing the web site of the NASA LLCD  project, specifically, NASA has begun to develop technologies such that may be suitable for high-throughput communication between satellites, using a digital encoding on optical signals, in real "outer space." Of course, there would also be some complex satellite positioning algorithms being required, in the same -- the network being absent of an effective "cable" between each of the respective light-signal endpoints -- that the system appears to function in a manner broadly analogous to a hypothetical system of a flashlight (or rather, a laser) and a lens, each in a digital circuit, moreover absent of intervening "air".

If the optical networking technologies used in the LLCD project might be -- in some ways -- analogous to conventional fiber optic media, then, and if the same technologies may be suitably miniaturized, perhaps such a possibility could be recognized commercially, and applied towards further production of that technology. Of course, it might not be viable for a "mass market," but it might be useful for application in further development of some emerging technologies -- such as, ostensibly, towards asteroid mining at orbital lagrange points above low earth orbit. No doubt, such systems as could be used in a by-in-large automated orbital asteroid mining system, those systems could function without continuous optical networking, but certainly it would not be a bad thing if a constant optical network was available as among the respective "mining satellites", and wherever the main "mining control people" would be, whether in orbit or (ostensibly with a repeater between the optical network and a radio network) on the ground.

Conceivably, if it may be possible to build the further OSI layers on top of that optical media, then -- perhaps, as in implementing an existing TCP/IP stack effectively onto such networking media, as could be approached in using Cisco's IOS and its QNX RTOS baseline, or an RTOS Linux implementation -- then, it might even be possible to implement CORBA in real "outer space". Of course, it would also need a suitably resilient digital electronics platform, for such a networking system to function continuously, in orbit.

Maybe one day, there could be CIsco routers in real "outer space."

Towards a TWI+PCI Implementation of IBM's Token Ring Network Architecture

The following is a verbatim copy of a response I'd written for a private discussion forum at an online university, this day. The discussion, essentially, was towards a comparison and contrast of a number of network technologies applied at "Layer 0" of the OSI seven layer model. My response, in this item, focuses specifically about token passing, as used in each of FDDI networking and in token ring networking, among all available digital systems interconnects. 

The topic of token ring networking has particularly caught my attention as a developer, considering the possibility of refactoring the technology for application onto I2C interconnets, for application ostensibly within a parallel computing model incorporating CORBA. In my response, after the items about token passing in token ring networking, I've begun "taking some notes," towards such an ostensible redesign of token ring networking for a parallel computing model onto I2C and PCI interconnects.


Token access, or token passing is a network flow control technique used in token-ring networks. The technologies for token ring networking were originally developed by IBM, in the 1970's , and may still be applicable in some network environments -- for instance, where network fault tolerance is a high priority, such as in networked industrial automation and measurement environments.

A token ring network utilizes a star topology, in which a multistation access unit (MAU) provides ports for eight individual hosts, additionally one port for a ring in cable and one port for a ring out cable. Effectively, the MAUs are connected in a ring, with individual hosts each connected to a single MAU. Infoar as it being a "star" network topology, geometrically it's not exactly like the conventional multi-connected, five-pointed star, might seem perhaps more like a ring with "leaf" nodes.

On a token ring network, after the network is initialized and an active monitor station determined on the network,  an electronic token is sent onto the network and transferred from station to station, until arriving at a station that has data to send on the network. 

At the sending station, a single bit in the token frame is changed before retransmit, thus transforming the token frame into a start-of-frame sequence for an information frame. Information is then appended to the start-of-frame sequence, that information necessarily including an address of a specific format (byte?) identifying the intended receiving station for the token. 

The information frame is then transmitted onto the network, and successively retransmitted -- whether along the MAUs only? or entirely from host to host --  until arriving at the intended receiving station. The receiving station then copies the information frame, sets two bits in the information frame to indicate that it has received the information, and will retransmit the information frame. The information frame then continues around the network until arriving at the original sending station. 

Due to the application of the token passing technique, data collision is effectively not a concern on a token ring network


Network token passing is also used in FDDI networking

Works referenced:
[1]  Cisco DocWiki Token Ring/IEEE 802.5 [2] CTDP  Token RIng.  The CTDP Network Certification Reference Version 0.6.2 

On a sidebar, with regards to developing a concept for an academic thesis ostensibly with regards to parallel computing: Token ring networking could be considered for a design of an I2C network. I2C is a "Wire protocol" available via interfaces in some single-board computing platforms and the Arduino microcontroller platform. In that regards, I would propose some notes, which I will presently try to extend on, in draft editions of this comment

• An I2C implementation of a token ring methodology would not necessarily require an application of an MAU, per se.
• I've not studied up about a lot of the details of I2C and the corresponding TWI protocol, however I've read that each utilizes some sort an addressing format, and a sort of centralized, single "master" design, fundamentally, in which one I2C device is a single "master" device, and would indicate via synchronization with clock signals, the address of an intended "receiving" device, before sending data to that receiving device. All devices on the I2C network would be, effectively, "Listening" at all times, no the I2C network, to detect when the "master" device indicates that a datum is to be sent on the network, and to indicate the peer address of the device to which the datum is to be sent, then to indicate the end of the transmission to that device. (Of course, I should wish to review an exacting, authoritative reference about I2C and/or TWI, at that. I've been of a presumption that it would allow for a "Multi-master' protocol to be defined -- focusing on TWI -- however, I'm not certain of how that might be approached in the exact "Wire protocol.") 
• The ostensible I2C token ring implementation could be designed such that it would be a "Signle mastering" protocol, in which the single "master' device would be the active monitor station of the I2C Token Ring 
• Each device on the I2C token ring network would need exactly two I2C interfaces, such that one would be the device's on I2C or rather, "TWI ring in" and the other, the "TWI ring out"
• Termination of a TWI ring network : If it was implemented in a pre-designed hardware configuration, the hardware could be designed such that it would define a "Built in ring". I need to study more about I2C or TWI, to specify how that could be approached, in a high-level view of the wiring. 
• Extensibility of a TWI ring network: The Monitor/Master device could be defined effectively as to provide exactly two ring network interfaces -- one for an "on board' ring, and one for an "on PCI bus" ring, if the hardware of the device network was implemented with a PCI interface on a single PCB. Then, each PCB should need to be identified with a "board number," as well as each I2C device on the PCB being identified with a "Device number", thus creating effectively a two-part addressing protocol for messages across the entire TWI "ring" including devices on other PCBs
• Termination of a ring network as designed onto TWI + PCI interfaces: On the PCI interface, the network could be designed more like an IBM token ring network, insofar as that a single "active monitor" would identify itself, and the other PCBs on the network would be designed as to acknowledge the designation of the "active monitor". 
• Once the networking and addressing protocols would be specified, then it could be possible to develop a peer-to-peer or client-server application on the network, e.g using the existing work of the CORBA specifications, specifically focusing on GIOP ostensibly for extension onto any single static-model TWI/PCI Token Ring Network, ostensibly for developing a parallel computing model such as could be implemented within a single PC architecture, using conventional PC peripheral interfaces including PCI.
• It might seem unorthodox, in some ways -- if not altogether unoriginal -- if simply for it being an extension of existing electronics protocols. Of course, if it could be towards the development of a useful parallel computing model, then certainly one would wish to inquire as to what parallel computing could be used for, in real-world applications within contemporary enterprise. Personally, I'm more concerned about the hardware design, at this time. I think it could be useful in an artificial neural network design, but I've not read a lot about that, and neither about statistical computing.