I've been looking at the current state of the vlan plugin to
ipdevpoll, but it was quite unfinished and I decided to write
something from scratch.
I'm writing a plugin based solely on BRIDGE-MIB and Q-BRIDGE-MIB.
Since Cisco has poor or no support for the latter, I'll later be
writing a plugin to collect VLAN information from Cisco proprietary
My question is:
Setting the vlan value of an interface record (previously swport)
usually means the "configured" VLAN of that port. But there are
possibly two ways to collect this from the Q-BRIDGE-MIB, and they have
subtly different meanings.
The options are basically ingress and egress VLANs. Q-BRIDGE holds a
table of ports  with a VLAN (PVID) value for each. This is the
VLAN assigned to any untagged ethernet frame coming in on that port.
Then there is a table of active VLANs , each with a column listing
egress ports that will send tagged or untagged frames from this VLAN.
Which one should we choose? Should we look at both and do some sort
of magic if they differ?