12,040 research outputs found
Full TCP/IP for 8-Bit architectures
We describe two small and portable TCP/IP implementations fulfilling the subset of RFC1122 requirements needed for full host-to-host interoperability. Our TCP/IP implementations do not sacrifice any of TCP's mechanisms such as urgent data or congestion control. They support IP fragment reassembly and the number of multiple simultaneous connections is limited only by the available RAM. Despite being small and simple, our implementations do not require their peers to have complex, full-size stacks, but can communicate with peers running a similarly light-weight stack. The code size is on the order of 10 kilobytes and RAM usage can be configured to be as low as a few hundred bytes
Challenges Using the Linux Network Stack for Real-Time Communication
Starting in the early 2000s, human-in-the-loop (HITL) simulation groups at NASA and the Air Force Research Lab began using the Linux network stack for some real-time communication. More recently, SpaceX has adopted Ethernet as the primary bus technology for its Falcon launch vehicles and Dragon capsules. As the Linux network stack makes its way from ground facilities to flight critical systems, it is necessary to recognize that the network stack is optimized for communication over the open Internet, which cannot provide latency guarantees. The Internet protocols and their implementation in the Linux network stack contain numerous design decisions that favor throughput over determinism and latency. These decisions often require workarounds in the application or customization of the stack to maintain a high probability of low latency on closed networks, especially if the network must be fault tolerant to single event upsets
Relaxing state-access constraints in stateful programmable data planes
Supporting the programming of stateful packet forwarding functions in
hardware has recently attracted the interest of the research community. When
designing such switching chips, the challenge is to guarantee the ability to
program functions that can read and modify data plane's state, while keeping
line rate performance and state consistency. Current state-of-the-art designs
are based on a very conservative all-or-nothing model: programmability is
limited only to those functions that are guaranteed to sustain line rate, with
any traffic workload. In effect, this limits the maximum time to execute state
update operations. In this paper, we explore possible options to relax these
constraints by using simulations on real traffic traces. We then propose a
model in which functions can be executed in a larger but bounded time, while
preventing data hazards with memory locking. We present results showing that
such flexibility can be supported with little or no throughput degradation.Comment: 6 page
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