Which company owns MAC address prefix A0:21:AA?

MAC address prefix A0:21:AA is registered to China Mobile Group Device Co.,Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:21:AA has a network interface built by China Mobile Group Device Co.,Ltd..

What is the OUI A0:21:AA?

A0:21:AA is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to China Mobile Group Device Co.,Ltd.. It covers every address from A0:21:AA:00:00:00 to A0:21:AA:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-21-AA.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in A0:21:AA:00:00:00 that is A0:21:AA — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.

Where is China Mobile Group Device Co.,Ltd. located?

China Mobile Group Device Co.,Ltd. is listed at 32 Xuanwumen West Street,Xicheng District Beijing CN 100053 in the IEEE OUI registry entry for A0:21:AA. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does China Mobile Group Device Co.,Ltd. own?

China Mobile Group Device Co.,Ltd. holds 76 OUI prefixes in the IEEE registry, of which A0:21:AA is one. A device made by China Mobile Group Device Co.,Ltd. could carry a MAC address from any of them.

China Mobile Group Device Co.,Ltd.

MAC address prefix A0:21:AA is registered to China Mobile Group Device Co.,Ltd. in the IEEE OUI registry. Any device whose MAC address begins with A0:21:AA has a network interface built by China Mobile Group Device Co.,Ltd.. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address — it covers every MAC from A0:21:AA:00:00:00 to A0:21:AA:FF:FF:FF.

OUI prefix: A0:21:AA
Hyphen form: A0-21-AA
MAC range: A0:21:AA:00:00:00 – A0:21:AA:FF:FF:FF
Addresses in block: 16,777,216
Organization: China Mobile Group Device Co.,Ltd.
Address: 32 Xuanwumen West Street,Xicheng District Beijing CN 100053
Source: IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.

Other prefixes from China Mobile Group Device Co.,Ltd.

China Mobile Group Device Co.,Ltd. holds 76 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2024-02-15Assigned to "China Mobile Group Device Co.,Ltd."
archived source →
2026-07-17Assigned to "China Mobile Group Device Co.,Ltd."

Nearby in the registry

The prefixes assigned immediately before and after A0:21:AA:

FAQ

Which company owns MAC address prefix A0:21:AA?: MAC address prefix A0:21:AA is registered to China Mobile Group Device Co.,Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with A0:21:AA has a network interface built by China Mobile Group Device Co.,Ltd..
What is the OUI A0:21:AA?: A0:21:AA is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to China Mobile Group Device Co.,Ltd.. It covers every address from A0:21:AA:00:00:00 to A0:21:AA:FF:FF:FF, or 16,777,216 addresses in total. It is also written A0-21-AA.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in A0:21:AA:00:00:00 that is A0:21:AA — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.
Where is China Mobile Group Device Co.,Ltd. located?: China Mobile Group Device Co.,Ltd. is listed at 32 Xuanwumen West Street,Xicheng District Beijing CN 100053 in the IEEE OUI registry entry for A0:21:AA. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does China Mobile Group Device Co.,Ltd. own?: China Mobile Group Device Co.,Ltd. holds 76 OUI prefixes in the IEEE registry, of which A0:21:AA is one. A device made by China Mobile Group Device Co.,Ltd. could carry a MAC address from any of them.