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Link down due to STP

Hi,

I have a basic question. When STP is putting a port in Blocking mode is the physical connection to the port down as well?

I had the problem that on one port the link to a server was down right after the port was in STP blocking state.

Maybe one could give me an explaination on this.

Thanks...Andy

Reply to
Andreas Heinzelmann
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No. The port has to stay up to keep receiving STP BPDUs even though it doesn't forward any traffic.

Dunno - sorry.

Sam

Reply to
Sam Wilson

"Sam Wilson" schrieb im Newsbeitrag news: snipped-for-privacy@scotsman.ed.ac.uk...

So a host on the port should not notice it at all, right?

Reply to
Andreas Heinzelmann

Err... no, but why would a switch block a port that a host was attached to?

Sam

Reply to
Sam Wilson

  1. because someone turned on bridging in the host, and spanning tree is doing exactly what it should as this is a loop bridging in windows XP sometimes gives this kind of hassle, but shouldnt be on a server....
  2. the host has the same MAC address on all ports and the switch got confused and put 1 port in err-disable (used to be common on a Sun box)
  3. 1 of the wierd mix ups that sometimes happen with link aggregation

- not setting it up on both ends, or mixing 802.1ad with cisco port aggregation....

any more?

slightly related - latest one i seem to get is Ethernet WAN links that reflect packets when there is an error (or when the transmission engineers are testing - they insist on looping circuits).

cisco routers dont seem to mind too much, but a Catalyst will err disable the port very quickly - and they dont auto recover by default....

Reply to
Stephen

I was really fishing to try to get the original poster to bring out that kind of issue.

I've never come across that as an issue causing err-disable. What circumstances does it happen in?

Anyway I was assuming (and looking back the assumption may have been wrong) that when the OP talked about STP blocking he was seeing his switch reporting a port in BLK mode. Reading back he may have been inferring (wrongly) that because a port was down it might be due to STP.

GigE negotiation mismatch.

Not seen that one (yet...). We have all our boxes set to recover from err-disable automatically - so much better than leaving the port down.

Sam

Reply to
Sam Wilson

claimed in an error report from hosting - something about turning off all the auto Pagp style stuff and plugging several ports into the same VLAN.

So do i now - but i wasnt expecting this as Ethernet WAN behaviour....

Had this on Marconi / Ericsson SDH muxes - looping the port is part of the diagnostics & commissioning routine.

Also got it from a misbehaving BT Redcare RS-1000-D (100 Mbps on a CCTV circuit).

Reply to
Stephen

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