White-Rabbit -> Data Delivery
Data delivered over White Rabbit network is divided into:
- Best Effort data - as in any standard Ethernet network,
- Critical data - unlike in a standard Ethernet network, White Rabbit Network provides deterministic and reliable method of data delivery
White Rabbit provides delivery of critical data
- with guaranteed upper bound latency
- in a deterministic way
- reliably
- transparently to "standard" (best effort) data delivery
White Rabbit critical data delivery is a combination of
- standard solutions (802.1Q priorities, VLANs, Quality of Service)
- hardware support to standard solutions
- enhancements to existing protocols
- Forward Error Correction techniques
White Rabbit critical data delivery method is
- a network-wide effort (it affects switches and nodes)
- compatible with standard Ethernet and interoperable with standard Ethernet gear
- handed in a sub-project: White Rabbit Network Robustness
Short description of critical data delivery in a White Rabbit Network
The critical data distributed over the White Rabbit Network is the one sent by a privileged controller-node (Data Master) in the payload of the Ethernet frame(s) which needs to be delivered to the nodes-to-be-controlled in a deterministic and reliable way. Therefore, the Data Distribution in the WRN is broken into:
- Critical Data - requires deterministic and reliable delivery
- Standard Data - non-critical, best effort delivery
The reliability of the White Rabbit Network depends on the successful delivery of the Critical Data to all the designated nodes. The worst-case upper bound of its delivery latency from the Data Master to any node in the network, regardless of it’s location (maximum distance from the Data Master), is required to be guaranteed by the network – this is a determinism requirement. Extremely low critical data loss (i.e. 1 per year) is required to guaranteed by the network - this is a reliability* requirement.
Detailed description of robustness in White Rabbit:
- An article about robustness in White Rabbit
- A presentation about critical data delivery (including usecaes of two future applications)
- Very detailed descriptions of the ideas:
Status
Design/development stage
3 July 2012