SPANNING TREE - GS105 Unmamaged switch

[sprocket]

Hi
I have a GS105 unmanaged switch and I am trying to find out what Spanning Tree protocols it supports.

I have looked at the dada sheet & install guide etc. but no joy.

If figure it MUST support good old 802.1d STP, but what about 802.1W RSTP?

Obviously it will not be configurable and any network self respecting network designer will have adjusted the values to sell a primary root bridge and a secondary root bridge, so that an unmanaged devices could never become root bridge.

The reason for the question is that putting an 802.1d only device into an RTSP 802.1w environment, undoes most of the good stuff that 802.1w RSTP gives you

Thanks
Sprocket

[beisser]

unmanaged means it doesnt support any spanning tree at all. how did you get the impression that it does support it?

[sprocket]

My assumption is that because it is a bridging device it must support STP, and at a minimum 802.1d. While it might be unmanaged, which to me means you cannot change the default parameters and you cannot do fancy things like security controls, it should still support the basic protocols associated with a bridging device.

I guess the only way to find out if it does support at least 802.1d is to connected to a managed Cisco switch running BPDU GUARD and see what the console reports.

Sprocket

[sprocket]

Well I plugged it into Managed switch (Cisco 3750) and began to have a look at some DEBUG messages

Switch#debug spanning-tree bpdu
Switch#
01:13:22: STP: VLAN0010 Gi1/0/1 tx BPDU: config protocol=ieee
Data : 0000 00 00 00 200A0013C4454000 00000000 200A0013C4454000 8001 0000 1400 0200 0F00
01:13:22: STP: VLAN0010 Gi1/0/5 tx BPDU: config protocol=ieee


So it supports basic STP. IEEE 802.1d, but when I set the upstream switch for 802.1w RSTP it did not exchange RSTP BPDUs.

It is also passes 802.1q packets (but spec sheet says it supports 802.1p anyway which implies it must handle 802.1 q even if transparently)

Job done - this UNMANAGED switch does participate in IEEE 802.1d STP

Sprocket

[beisser]

thats more than strange because its very well possible to build a loop with a gs105, which should not be possible if it supported spanningtree correctly.

very strange

[fordem]

Just out of curiosity - was that done with just a single cable connected to the GS105, to link it to the Cisco?