4

I have a use case where I need to determine whether two MAC addresses belong to the same router with dual band connection 2.4 GHz and 5 GHz.

When I did some study, I found that the MAC address of all WiFi APs serving 2.4 GHz and that of 5 GHz differ only by 2 in their last digits.

Example:

2.4 GHz MAC: aa:bb:cc:dd:ee:53
5 GHz MAC: aa:bb:cc:dd:ee:55

So is there any standard for dual band routers, that makes them follow this rule ? Also, if not this, is there any other way I can know whether the two MAC addresses are of the same router, but with different bands.

4

A company will register with the IEEE to get an OUI (Organizationally Unique Identifier). Beyond that, the company is free to assign MAC addresses within the OUI as it sees fit. There are no outside standards or requirements for how a company assigns MAC addresses within its OUI.

What you are asking can vary from manufacturer to manufacturer. There is nothing to which you can refer that explains it for all WAPs.

2

As the answers say, there's nothing official.

But in practice if two responding addresses differ by such a small amount then either they are a) identical units sequentially taken from the production line, or b) the same device, such as several interfaces on a router, bridge, switch, AP, etc.

So unless the situation is one where there's something covert going on ...

Situation A is in general pretty unlikely, it's only occasional even when you're fitting out factories or office floors. Situation B happens all the time,

So if you can use any kind of context you might be able to have a good guess about it. Does your need require the answer to be certain?

Do your devices send CDP or LLDP? Or answer SNMP? Those are all good ways to identify different ports of the same device.

0

I think the number that you are seeing that it changes is the part of the MAC that it up to the vendor, this number is the last 3 octets of the MAC address this and is regularly increased by one if the vendor Card or divice have more than one interface, this is up to the vendor MAC address allocation, I think this number changes by one by management because they need to know which MAC address is assigned to each device that they sell

MAC address composition

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