Company ID (CID)

A CID, like the OUI, is a unique 24-bit identifier. A CID though, cannot be used to generate universally unique MAC addresses. Therefore, the CID is especially applicable in applications where unique MAC addresses are not required. A CID should be applicable in most other cases where an OUI is specified. The CID has been created to reduce the consumption of OUI values.

For more information, please see the tutorial “Guidelines for Use of Extended Unique Identifier (EUI), Organizationally Unique Identifier (OUI), and Company ID (CID)“.

Registration Fees

Product Fees
One Time Fees  
Publicly Registered CID
(Company name & address will be displayed on the IEEE public listing)
US $855
Optional Recurring Fees  
Yearly Confidentiality Renewal Fee*
(Company name & address will NOT be displayed on the IEEE public listing)
US $1,380
* Assignees will also be required to pay an annual fee to maintain confidentiality. Payment options for the renewal fee are credit card, check or wire transfer. IEEE does not accept requests for applicant-specified identifiers.

Application Information

Please search the public listing to determine whether your organization has already been issued an assignment. If so, you may email us to obtain contact information for the assignment.

  1. Log in or create an account in order to apply for an assignment.
  2. A tracking number will be sent via email to the applicant. Any questions regarding your application will be sent via email to the primary email address provided at time of application.
  3. Applications are processed within seven (7) business days from receipt of payment. Be advised that the credit card will be charged once the application is submitted. Assignment details and a Paid Invoice will be available for download once the application is approved.
  4. Unless otherwise noted, applications are valid for 30 days.
  5. Since the public listing is updated once every 24 hours, new assignments will not be immediately viewable on the directory.

Related Standards

The OUI defined in IEEE 802®-2001 can be used to generate 48-bit Universal LAN MAC addresses to uniquely identify Local and Municipal Area Networks stations, and Protocol Identifiers to identify public and private protocols. These are used in LAN and MAN applications. The relevant standards include but not limited to:

  • CSMA/CD (IEEE 802.3™, ISO 8802-3)
  • Token Bus (IEEE 802.4™, ISO 8802-4)
  • Token Ring (IEEE 802.5™, ISO/IEC 8802-5)
  • IEEE 802.6™(ISO/IEC DIS 8802-6) FDDI (ISO 9314-2)
  • WLAN (IEEE 802.11™, ISO/IEC 8802-11)

The ‘company_id’ relevant standards as defined in IEEE 1212™-1991 Control and Status Register (CSR) Architecture referenced by IEEE 896.2™-1991 Futurebus+Physical Layers and Profiles include:

  • IEEE 1596™-1992 Scalable Coherent Interface
  • IEEE 1394™-1995 Serial Bus document. (In this context, the 24-bit company_id value is a portion of the 32-bit Module_Vendor_Id ROM location and related locations, and uniquely identifies hardware vendors and I/O software interface architectures)
  • ANSI X3.230-1994 Fibre Channel Standard

The IEEE Registration Authority will assign an additional OUI to any organization requesting one, providing they submit a letter on company letterhead to the IEEE Registration Authority c/o IEEE Standards Department, stating that their company will not “ship” product in the new block assignment until well after they have reached (shipped) at least 95% of the block assignment, in the context of a specified standard. Your company should ensure that large numbers of derived identifiers are not left unused.

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