As a data point, the way I've (and Nick Bastin, who actually wrote the
code) solved this in the FlowVisor is the chassis ID is still the mac
subtype and uses the MAC of the outgoing interface, but we added a
description TLV that contains the 8 byte datatpath id.
The reason why we did this is that older NOX's still expect the
subtype of MAC, so this would be better backwards compatible. Not
sure if you care, but something to think about. FYI, the relevant
code is in discovery.py:
# parse out chassis id
if lldph.tlvs[0].subtype != chassis_id.SUB_MAC:
log.err("lldp chassis ID subtype is not MAC,
ignoring",system='discovery')
return
- Rob
.
On Mon, Nov 15, 2010 at 6:55 PM, James "Murphy" McCauley <jam...@nau.edu> wrote:
> I know there's a longstanding issue with some switches that use more
> than 48 bits for their DPIDs. This problem stemming from the fact that
> discovery stuffs the DPID into a MAC subtype chassis ID TLV in the LLDP
> packet it sends out, which obviously only has 48 bits. Thus, when we
> get the LLDP packet back, the MAC/DPID in it doesn't match one of our
> DPIDs because the top bits have been stripped off.
>
> I notice that the chassis ID TLV also has a "local" subtype. According
> to 802.1AB-2005 (which isn't the current version), this is "an
> alpha-numeric string and is locally assigned". Can we just stuff the
> DPID in there as a string? Maybe prepend "dpid:" to weed out anything
> else that may use it and to look nice for other tools?
>
> I've attached a patch. Maybe someone would tell me what they think? I
> don't have any of the problematic switches to play with, though I did
> specify large dpids in OVS and had them work now.
>
> -- Murphy
>
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>
>
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