GE F650 User Manual page 258

B.1 PRP AND HSR ETHERNET PROTOCOLS
• The Redundancy Box (RedBox) is used when a single interface node has to be attached to both networks. Such a
node can communicate with all other nodes. Since a node behind a RedBox appears for other nodes like a DAN, it is
called Virtual DANs (VDAN). The RedBox itself is a DAN and acts as a proxy on behalf of its VDANs. The RedBox has
its own IP address for management purposes
Similarly to PRP, HSR is based in the duplication of every frame sent, but in a ring topology. Each copy of the frame is
injected in a different direction of the ring. If any of the links between nodes is down, all nodes are still reachable. This
topology forces every node in the net to be HSR aware because they have to forward every message until it reaches its
destination. With that purpose, the redundancy information is located at the beginning of the frame allowing a faster
forwarding, see next figure.
B
Definitions:
• PRP – Parallel Redundancy Protocol - redundancy protocol for high availability in substation automation networks
based on IEC 62439-3 Clause 4 and applicable to networks based on Ethernet technology (ISO/IEC 8802-3).
• OSI - Open Systems Interconnection - model defined by the International Organization for Standardization (ISO) for
standardizing the functions of a communication system in terms of abstraction layers. Similar communication functions
are grouped into logical layers. A layer serves the layer above it and is served by the layer below it. There are 7 layers:
physical, data link, network, transport, session, presentation, application.
• DANP – Doubly Attached Node running PRP – a node that has two ports which operate in parallel and are attached to
the upper layers of the OSI communications stack through a Link Redundancy Entity module.
• DANH – Doubly Attached Node with HSR protocol.
• LRE - Link Redundancy Entity – module operating at the link layer of the OSI stack and responsible for handling
duplicates and managing redundancy.
• SAN – Singly Attached Node – regular nodes with non-redundant network adapters
• RedBox – device attaching singly attached nodes (SANs) to a redundant network.
B-2
Figure B–2: EXAMPLE OF HSR WITH HSR RING
F650 Digital Bay Controller
APPENDIX B
GEK-113000AE