[j-nsp] EX4200 LLDP issue with vlan-tagging

[Chuck Anderson]

On Tue, May 10, 2011 at 08:51:31AM -0600, Stacy W. Smith wrote:
> I hate trying to read IEEE standards, but after a cursory glance I
> would agree that the behavior your seeing on the vlan-tagged family
> inet interface is not correct.
> 
> I didn't see anything specifying one way or another in the
> 802.1AB-2005 (LLDP) standard, but the 802.1Q-2005 standard says this
> in Table 9-2: "The null VLAN ID. Indicates that the tag header
> contains only priority information; no VLAN identifier is present in
> the frame. This VID value shall not be configured as a PVID or a
> member of a VID Set, or configured in any Filtering Database entry,
> or used in any Management operation."
>
> I interpret "or used in any Management operation" to exclude the use
> of a vlan tag value of 0 for LLDP frames.

I don't interpret it that way--I think they are talking about
Management of the switch's VLAN configuration, SNMP, etc, not about
the on-the-wire format of any/all management ethernet frames...but
then again I only read the excerpt you posted, so perhaps it is
clearer in context.

> Of course the simple fact that the two different configuration are
> producing different frame formats should be enough to get JTAC to
> investigate more thoroughly.

On the contrary, I think it is perfectly reasonble to expect two
different configuration to operate differently :-) I would say that
given how JUNOS has typically operated, I would not expect a Layer 3
VLAN interface to participate in any Layer 2 protocols at all--no STP,
LLDP, etc. If you want Layer 2 protocols, use a Layer 2 interface
with an RVI.