42 lines
2.9 KiB
ReStructuredText
42 lines
2.9 KiB
ReStructuredText
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The Cubesat Space Protocol
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==========================
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Cubesat Space Protocol (CSP) is a small protocol stack written in C. CSP is designed to ease communication between distributed embedded systems in smaller networks, such as Cubesats. The design follows the TCP/IP model and includes a transport protocol, a routing protocol and several MAC-layer interfaces. The core of libcsp includes a router, a socket buffer pool and a connection oriented socket API.
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The protocol is based on a 32-bit header containing both transport and network-layer information. Its implementation is designed for, but not limited to, embedded systems such as the 8-bit AVR microprocessor and the 32-bit ARM and AVR from Atmel. The implementation is written in GNU C and is currently ported to run on FreeRTOS or POSIX operating systems such as Linux.
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The idea is to give sub-system developers of cubesats the same features of a TCP/IP stack, but without adding the huge overhead of the IP header. The small footprint and simple implementation allows a small 8-bit system with less than 4 kB of RAM to be fully connected on the network. This allows all subsystems to provide their services on the same network level, without any master node required. Using a service oriented architecture has several advantages compared to the traditional mater/slave topology used on many cubesats.
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* Standardised network protocol: All subsystems can communicate with eachother
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* Service loose coupling: Services maintain a relationship that minimizes dependencies between subsystems
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* Service abstraction: Beyond descriptions in the service contract, services hide logic from the outside world
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* Service reusability: Logic is divided into services with the intention of promoting reuse.
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* Service autonomy: Services have control over the logic they encapsulate.
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* Service Redundancy: Easily add redundant services to the bus
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* Reduces single point of failure: The complexity is moved from a single master node to several well defines services on the network
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The implementation of LibCSP is written with simplicity in mind, but it's compile time configuration allows it to have some rather advanced features as well:
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Features
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--------
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* Thread safe Socket API
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* Router task with Quality of Services
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* Connection-oriented operation (RFC 908 and 1151).
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* Connection-less operation (similar to UDP)
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* ICMP-like requests such as ping and buffer status.
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* Loopback interface
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* Very Small Footprint 48 kB code and less that 1kB ram required on ARM
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* Zero-copy buffer and queue system
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* Modular network interface system
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* Modular OS interface, ported to FreeRTOS, windows (cygwin) and Linux
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* Broadcast traffic
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* Promiscuous mode
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* Encrypted packets with XTEA in CTR mode
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* Truncated HMAC-SHA1 Authentication (RFC 2104)
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LGPL Software license
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---------------------
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The source code is available under an LGPL 2.1 license. See COPYING for the license text.
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