User`s manual

EDS-828 Series User’s Manual Featured Functions
3-20
Using Communication Redundancy
Setting up Communication Redundancy on your network helps protect critical links against failure,
protects against network loops, and keeps network downtime at a minimum.
The Communication Redundancy function allows the user to set up redundant loops in the network
to provide a backup data transmission route in the event that a cable is inadvertently disconnected
or damaged. This feature is particularly important for industrial applications, since it could take
several minutes to locate the disconnected or severed cable. For example, if the EDS-828 is used
as a key communications component of a production line, several minutes of downtime could
result in a big loss in production and revenue. The EDS-828 supports three different protocols to
support this communication redundancy function— Rapid Spanning Tree/ Spanning Tree
Protocol (IEEE 802.1w/1D), Turbo Ring, and Turbo Ring V2.
When configuring a redundant ring, all switches on the same ring must be configured to use the
same redundancy protocol. You cannot mix the “Turbo Ring,” “Turbo Ring V2,” and STP/RSTP
protocols on the same ring. The following table lists the key differences between each feature. Use
this information to evaluate the benefits of each, and then determine which features are most
suitable for your network.
Turbo Ring V2 Turbo Ring STP RSTP
Topology Ring Ring Ring, Mesh Ring, Mesh
Recovery Time < 20 ms < 300 ms Up to 30 sec. Up to 5 sec
NOTE
Most of Moxa’s managed switches now support two proprietary Turbo Ring protocols:
1. “Turbo Ring” refers to the original version of Moxa’s proprietary redundant ring
protocol, which has a recovery time of under 300 ms.
2. “Turbo Ring V2” refers to the new generation Turbo Ring, which has a recovery time of
under 20 ms.
In this manual, we use the terminology “Turbo Ring” ring and “Turbo Ring V2” ring to
differentiate between rings configured for one or the other of these protocols.
Gigabit Ethernet Redundant Ring Capability (< 50 ms)
Ethernet has become the default data communications medium for industrial automation
applications. In fact, Ethernet is often used to integrate video, voice, and high-rate industrial
application data transfers into one network. The EDS-828, which comes equipped with a
redundant Gigabit Ethernet protocol called Gigabit Turbo Ring, gives system maintainers a
convenient means of setting up a versatile yet stable Gigabit Ethernet network. With Gigabit
Turbo Ring, if any segment of the network gets disconnected, your automation system will be
back to normal in less than 300 ms (Turbo Ring) or 50 ms (Turbo Ring V2).
The Turbo Ring Concept
The Turbo Ring and Turbo Ring V2 protocols identify one switch as the master of the network,
and then automatically block packets from traveling through any of the network’s redundant loops.
In the event that one branch of the ring gets disconnected from the rest of the network, the protocol
automatically readjusts the ring so that the part of the network that was disconnected can
reestablish contact with the rest of the network.