User`s guide

OVERVIEW
Page 10 User’s guide ref 9018809-01 XSRING+ SHDSL switch
3.2 Redundancy solutions: RSTP and proprietary failsafe ring
Industrial applications need reliable networks; one way to provide reliability is to provide backup paths
which form loops in the Ethernet network.
However, loops are highly unwelcome in Ethernet networks, as they can cause broadcast storms,
eating up all the available bandwidth and causing network outage.
The goal of redundancy protocols is to make Ethernet work of networks containing loops and to
provide a path at each time, even, if possible, when one or several links are in failure.
The XSRING provides two solution to handle redundancy :
RSTP
RSTP, standing for "Rapid Spanning Tree Protocol" is specified by the IEEE in the 802.1D-2004
document.
RSTP can handle complex structures ; RSTP can be used with devices from other manufacturers.
The failure detection delay and the recovery delay in an shdsl network is around 10 seconds.
Proprietary failsafe ring algorithm
Based on the STP algorithm, that solution makes possible to handle a ring structure up to 16 SHSDL
switches.
The advantages of that solution is that the failure detection delay and the recovery delay is only a few
seconds (One second if the ring counts 5 SHDSL switches); moreover, it is very simple to configure.