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March 12th, 2015 09:00
iSCSI switches and Spanning Tree configuration for management ports
Hi,
I have a pair of power connect N2024 switches being used for iSCSI and configured using the "Dell Switch Configuration Guide for EqualLogic SANs"
I have attached a diagram showing the configuration.
The N2000 series does not have a dedicated out of band interface so you have to configure one by using a VLAN on the switch just for this purpose. An IP interface is then configured on this VLAN for the management and it is assigned to a single physical port, in this example port 24 to be uplinked to the LAN.
The problem is the management ports (VLAN 150) are receiving STP changes from the LAN (no problem here) however the port-channel group connecting the two N2024 switches which is currently configured in Access mode in VLAN 100, is then being shut down by spanning Tree!
My question is why is this happening? If the Portchannel was access VLAN 150 it would make sense, but its not its VLAN 100.
Any info appreciated.
Kind regards
Dave
Stem_Dave
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March 12th, 2015 14:00
I was under the impression spanning tree needed to see the same packets on both interfaces to then invoke a blocked port? obviously this is not correct as it is shutting down links that cannot cause a loop! There is not way packets from vlan 150 on a port in VLAN 100 ?
Stem_Dave
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March 12th, 2015 14:00
Also I am sure we have this exact same configuration but with better models (N3000 / 4000) which have dedicated OOB ports, these do not suffer from this problem, I assume as the OOB interfaces are on a different fabric ?
Stem_Dave
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March 12th, 2015 14:00
The switches are next to each other and are the suggest dell configuration of non stacked, we came to the same conclusion as Dell over this as maintenance can then be performed on the switches without taking down the iscsi network.
Stem_Dave
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March 13th, 2015 07:00
Hi DELL-Daniel,
OK, so if we are trying to replicate the setup of a dedicated OOB port but with a VLAN we should turn off spanning tree on the OOB management ports? After all these are just single interfaces on the switch and are used purely for management not routed traffic etc from the switch.
You could then leave spanning tree enabled on the portchannel to stop any accidental links between the two switches on the iscsi VLAN being connected in error, thus keeping the switch working if this should happen?
So to recap, enable spanning tree on the Port channel and disable on the OOB ports.
Would you agree with this?
Cheers
Dave
PS, Are you a DELL employee ?