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[sdonnet]

Hi,

I have several D'Link switches connected together... At least one DGS-1210-48 and one DES-3526. They are "RSTP" enabled...

Sometimes, during 1 to 2 minutes, we have a huge loss of packets... As these switchs log infos to a syslog server, we have in this log messages coming from these 2 switch :

from the DGS-1210-48 :
Apr 19 16:19:13 XX.XX.XX.254 2011:STP-6:Topology changed  [( port: 39)]
Apr 19 16:19:15 XX.XX.XX.254 2011:STP-6:Topology changed  [( port: 39)]
...
from the DES-3526 :
Apr 19 17:39:58 XX.XX.XX.253 INFO: Topology changed
Apr 19 17:39:58 XX.XX.XX.253 INFO: Topology changed

port 39 is the port from DGS-1210-48 to the DES-3526. It is "auto-enable".

My question is quite simple :
Is "topology changed" a problem of RSTP or a problem of speed/duplex/autoenable setting ?

[TimotiSt]

Hi,

"Topology change" is an STP thing. It can be triggered either by links going up/down, or by introducing a new STP bridge on a network. If the new bridge becomes the new root bridge, it can trigger a new convergence of the entire STP domain, disrupting communications even for 30-50 seconds.

If you enable STP on ports facing end-user computers, if someone plugs in a computer running STP (Linux box, Windows machine configured with bridging, or running some VMWare software, etc.), that can cause problems.

Just to be sure, check out the cable quality between the two D-Link switches, make sure it's not flapping (faulty cable, receiving EMP from an elevator, etc.).

Hope it helps!
Cheers,
Tamas