09-16-2011 09:41 PM
these protocol are suitable to provide ring protection over metro-rings in comparison to conventional STP/MSTP/RSTP which is used normal ethernet scenarios ...
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09-17-2011 07:37 AM
Thanks for the response, but I'm still not clear. If ERPS is used to block ports on a ring, then what purpose does MSTP serve, seeing's how it could take up to a minute to propogate topology changes?
09-19-2011 12:29 PM - edited 09-19-2011 12:44 PM
MSTP does not take a minute to converge, it's based on RSTP(inside MSTP domain) and it's really fast.
If properly engineered it gives really good results.
Regarding your question, ERPS only helps when you have ring topologies but it's not suitable for mesh ones, so in order to be on the safe side you better run both, otherwise you risc a lot as any unexpected loop can bring the whole network down.
09-26-2011 04:19 AM
MSTP on the other hand caters for dynamic and unexpected topologies (the human factor), because it will converge any topology thrown at it to be loop-free.
There are definitely ways to mitigate against loops in a metro environment so that you no longer need MSTP (shut down non-ring ports, tunnel or filter customer L2 protocols etc), but at the end of the day it comes down to risk.
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