Content deleted Content added
not modifiers |
review complete: format ref. rm rep. |
||
Line 61:
TTEthernet provides the lowest possible latency in transferring data across the network by using time-___domain control methods – each time triggered transfer is scheduled at a specific time so that contention for shared resources is controlled and thus the possibility of congestion is eliminated. The switches in the network enforce this timing to provide tolerance of faults in, and malicious actions on the part of, the other connected equipment. However, "synchronized local clocks are the fundamental prerequisite for time-triggered communication".<ref>Wilfried Steiner and Bruno Dutertre, [http://www.csl.sri.com/users/bruno/publis/fmics2010.pdf ''SMT-Based Formal Verification of a ''TTEthernet'' Synchronization Function''], S. Kowalewski and M. Roveri (Eds.), FMICS 2010, LNCS 6371, pp. 148–163, 2010.</ref> This is because the sources of critical data will have to have the same view of time as the switch, in order that they can transmit at the correct time and the switch will see this as correct. This also requires that the sequence with which a critical transfer is scheduled has to be predictable to both source and switch. This, in turn, will limit the transmission schedule to a highly deterministic one, e.g. the [[cyclic executive]].
However, low latency in transferring data over the bus or network does not necessarily translate into low transport delays between the application processes that source and sink this data. This is especially true where the transfers over the bus or network are cyclically scheduled (as is commonly the case with MIL-STD-1553B and STANAG 3910, and necessarily so with AFDX and TTEthernet) but the application processes are not synchronized with this schedule.
With both AFDX and TTEthernet, there are additional functions required of the
==References==
| |||