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IDProjectCategoryView StatusLast Update
2049RackTables802.1Q VLANspublic2021-09-05 14:46
Reporteriopsthecloud Assigned Toinfrastation  
Status closedResolutionno change required 
Product Version0.21.4 
Summary2049: unable to have same mac address on 2 objects enven if thse objects are on 2 different 802.3 domains.
DescriptionWe have 2 use cases with identical MAC addresses.

The first concerns MAC addresses that are reused on separate and isolated Ethernet segments. This can happen in particular in data centres that are independent of each other.

The second use case concerns special interfaces such as CARP interfaces under *BSD for which MAC addresses are dynamically constructed from external elements. This is the same as the previous case of having duplicate MAC addresses on separate Ethernet segments.
TagsNo tags attached.




2021-08-26 15:25

administrator   ~0004353

The currently implemented data model allows a port MAC address to be duplicate only on a port of the same device. in other words, any two different devices must not use the same MAC address. To the best of my knowledge, this is consistent with the definition of Ethernet as an IEEE standard (less the special-purpose destination addresses, which are not assigned to ports and thus not documented in RackTables).

If you can point to a particular technical specification to support the need to legalize duplicate source addresses, please do so. However, it would take time to relax the database constraint safely. Alternatively, you could make the MAC addresses unique (so long as you seem to be in control of the address value), which would automatically eliminate a space for potential fault if things go wrong and segments that are not bridged now become bridged later.


2021-08-26 18:34

reporter   ~0004355

MAC address can be duplicated at many times. Each vendor have a pool delegated by IANA and pools used for special purpose, like

As reminder, the uniqueness of address MAC must be true at the LLC/MAC level of the OSI Model. At the vendor scale, MAC address are not unique globally, it must be unique in the broadcast domain.

About the constraint, we already patch our version, it's not a DB constraint.

function assertUniqueL2Addresses ($db_l2addresses, $my_object_id)

On our side, we are reimplementing the function to have better granularity to take care of the MAC address prefix and if ports are linked to the same broadcast domain.


2021-09-05 14:46

administrator   ~0004357

Thank you for your comments. It is a bit unfortunate that we were talking past each other, but I have other work to do.

Issue History

Date Modified Username Field Change
2021-08-24 15:53 iopsthecloud New Issue
2021-08-26 15:25 infrastation Note Added: 0004353
2021-08-26 18:34 iopsthecloud Note Added: 0004355
2021-09-05 14:46 infrastation Assigned To => infrastation
2021-09-05 14:46 infrastation Status new => closed
2021-09-05 14:46 infrastation Resolution open => no change required
2021-09-05 14:46 infrastation Note Added: 0004357