IOI (Inter-operator identifier)

An Inter-operator identifier (IOI) is a unique identification code used in the telecommunications industry to identify a specific operator or network. IOIs are primarily used in signaling messages exchanged between different operators to facilitate call routing and other network functions.

IOIs are critical for ensuring the proper routing of voice, data, and signaling traffic between operators. They allow operators to identify each other, exchange routing information, and route traffic to the appropriate destination. IOIs are used in various telecommunications protocols, including Signaling System 7 (SS7), Session Initiation Protocol (SIP), and Diameter.

In this article, we will delve deeper into the topic of IOIs and cover the following aspects:

1. What is an IOI?
2. How are IOIs used in telecommunications networks?
3. How are IOIs assigned and managed?
4. Examples of IOIs used in different regions and countries.

What is an IOI?

An IOI is a unique identifier used to identify a specific operator or network. It is typically a short alphanumeric code consisting of three to five characters. IOIs are used in signaling messages exchanged between operators to identify the originating or terminating network and to route traffic to the appropriate destination.

For example, when a user initiates a call from a mobile phone on one network to a mobile phone on another network, the two networks exchange signaling messages to establish the call. These signaling messages include IOIs to identify the originating and terminating networks. The IOIs are used by the signaling network to route the call to the appropriate destination.

IOIs can also be used for other purposes, such as identifying the type of service or equipment being used, identifying the location of the user, or identifying the billing entity responsible for the call.

How are IOIs used in telecommunications networks?

IOIs are used in various telecommunications protocols to identify operators and networks and to facilitate call routing and other network functions. Some of the protocols that use IOIs include:

1. Signaling System 7 (SS7) – SS7 is a protocol used for signaling and call setup in the public switched telephone network (PSTN) and other telecommunications networks. IOIs are used in SS7 signaling messages to identify the originating or terminating network and to route traffic to the appropriate destination.
2. Session Initiation Protocol (SIP) – SIP is a protocol used for initiating, modifying, and terminating real-time sessions, such as voice and video calls, over IP networks. IOIs are used in SIP messages to identify the originating or terminating network and to route traffic to the appropriate destination.
3. Diameter – Diameter is a protocol used for authentication, authorization, and accounting (AAA) in 4G and 5G mobile networks. IOIs are used in Diameter messages to identify the operator or network that is requesting the service and to route traffic to the appropriate destination.

In addition to call routing, IOIs are also used for other purposes in telecommunications networks, such as:

1. Network management – IOIs are used to identify the operators and networks involved in a call or transaction, which can be useful for network management and troubleshooting.
2. Fraud prevention – IOIs can be used to identify fraudulent activity, such as call spoofing or call hijacking, by detecting anomalies in the IOIs or other signaling information.
3. Roaming – IOIs are used to identify the home and visited networks of a roaming subscriber, which is important for billing and other network functions.

How are IOIs assigned and managed?

IOIs are assigned and managed by various organizations, depending on the region and country. In some cases, IOIs are assigned by telecommunications regulators or industry associations, while in other cases they are assigned by individual operators or network providers.

In North America, IOIs are assigned by the North American Numbering Plan Administration (NANPA), which is a neutral third-party organization responsible for administering the numbering plan for the North American Numbering Plan (NANP). The NANP covers the United States, Canada, and various Caribbean countries.

In Europe, IOIs are assigned by the European Telecommunications Standards Institute (ETSI), which is a standardization organization that develops standards for telecommunications networks and services in Europe. ETSI assigns IOIs through its Numbering and Addressing (NA) committee, which is responsible for managing the European numbering plan.

In other regions, IOIs may be assigned by national telecommunications regulators or industry associations. For example, in Japan, IOIs are assigned by the Telecommunications Carriers Association (TCA), which is an industry association representing the major telecommunications operators in Japan.

IOIs are typically assigned based on a set of rules and guidelines that ensure their uniqueness and consistency. For example, IOIs may be assigned based on geographical location, operator type, or other factors. The rules and guidelines for IOI assignment may vary by region and country.

Once assigned, IOIs are typically managed by the operator or network provider to which they are assigned. This includes ensuring that the IOIs are used appropriately in signaling messages and other network functions, and that they are not duplicated or used by unauthorized parties.

Examples of IOIs used in different regions and countries

IOIs are used in various regions and countries around the world. Some examples of IOIs used in different regions include:

1. North America – In the United States and Canada, IOIs typically consist of three digits and are assigned by the NANPA. For example, the IOI for Verizon Wireless is 310-004.
2. Europe – In Europe, IOIs typically consist of three to five digits and are assigned by ETSI. For example, the IOI for Orange in France is 208-01.
3. Japan – In Japan, IOIs typically consist of four digits and are assigned by the TCA. For example, the IOI for NTT Docomo is 440-10.
4. Australia – In Australia, IOIs typically consist of five digits and are assigned by the Australian Communications and Media Authority (ACMA). For example, the IOI for Telstra is 50501.

Conclusion

In summary, an Inter-operator identifier (IOI) is a unique identification code used in the telecommunications industry to identify a specific operator or network. IOIs are critical for ensuring the proper routing of voice, data, and signaling traffic between operators. They are used in various telecommunications protocols, including SS7, SIP, and Diameter, and are assigned and managed by various organizations, depending on the region and country. By understanding IOIs and how they are used, we can gain a better understanding of how telecommunications networks operate and how they are interconnected.