07-27-2007 03:08 AM - edited 03-05-2019 05:31 PM
Hi dears,
A customer of mine wants to use two interconnected clatalyst 4500R switch on a redundant industrial network. One computer is connected to a 2800 switch that is connected to both 4500R. On the otherside of the network, a PLC is also connected to a 2800 that also connect to both 4500R.
I know that spanning tree protocol will prevent the loops and close redundant port. In case of failure of a network device, then the redundant port will be opened and the traffic will pass through this new route.
What I want to know is on wich OSI level this works. how does the switch sees that traffic can not be forwarded. We do not use TCP/IP for our connection, but directly mac adresses, will this trafic also be routed to the correct adress in case of failure?
Thanks for your help
07-27-2007 04:09 AM
Hi,
STP works on layer 2 of the OSI reference model. It works on the basis of mac-addresses of the bridges/switches and there are packets called BPDU's( Bridge Protocol Data Unit) which are exchanged between the switches and have information which leads to the STP process completion.
STP process puts redundant paths into blocking mode and in case of failure of the primary path, stp process is again calculated to open up the blocking port.
Please find below the link which would give you further clarity on the STP process.
Manmeet
07-27-2007 04:12 AM
Sorry,
Forgot to post the link:
Pls rate if helpful.
Manmeet
07-30-2007 12:21 AM
Thank you so much for your help. It seems that I can not follow the link with my account. Anyway, your answer was very helpfull, thanks again.
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