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IAM (Initial Address Message)

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5G & 6G Prime Membership Telecom

IAM (Initial Address Message) is a key message in telecommunication networks that is used to initiate a call or session. It is a signaling message that is used to establish a connection between two devices, such as a telephone or computer, in order to exchange data or voice communications. The IAM message contains important information about the call, such as the called and calling party's numbers, the type of service being requested, and the type of network being used. In this article, we will provide a detailed explanation of IAM, its components, and its significance in telecommunications networks.

IAM Basics

IAM is the first message that is sent by the calling party's device to the network when a call is initiated. It is sent over the Signaling System 7 (SS7) network or over a digital interface such as Primary Rate Interface (PRI) or a Session Initiation Protocol (SIP) trunk. The IAM message contains information that is essential for establishing a connection between the two devices and routing the call to its destination. The message is usually transmitted in a digital format using the ISDN User Part (ISUP) protocol.

IAM Components

The IAM message consists of several components that convey information about the call to the network. These components include:

  1. Nature of Connection Indicators (NCI): The NCI field contains information about the type of call being made, such as voice, data, or fax. It also indicates whether the call is incoming or outgoing.
  2. Calling Party Number (CPN): The CPN field contains the phone number of the calling party. This number is used by the network to identify the calling party and route the call to the correct destination.
  3. Nature of Address Indicators (NAI): The NAI field contains information about the type of address used in the CPN field. For example, it may indicate whether the number is an international number, a national number, or a local number.
  4. Called Party Number (CPC): The CPC field contains the phone number of the called party. This number is used by the network to identify the destination of the call.
  5. Nature of Address Indicators (NAI): The NAI field in the CPC component contains information about the type of address used in the CPC field.
  6. Forward Call Indicators (FCI): The FCI field contains information about the type of call forwarding that is required, such as unconditional or busy call forwarding.
  7. Optional Forward Call Indicators (OFCI): The OFCI field contains additional information about call forwarding, such as the number of times the call has been forwarded.
  8. Original Called Number (OCN): The OCN field contains the original called party number. This is used when a call is forwarded to a different number or destination.
  9. User-to-User Information (UUI): The UUI field is used to transmit additional information between the calling and called parties, such as caller ID or call priority.

Significance of IAM

The IAM message is a critical component of the telecommunication network because it is used to establish a connection between two devices and route the call to its destination. The message contains important information about the call, such as the calling and called party numbers, the type of service being requested, and the type of network being used. Without this information, the network would not be able to establish a connection between the two devices and the call would not be completed.

IAM messages are used in a variety of telecommunication networks, including fixed-line and mobile networks. They are also used in Voice over Internet Protocol (VoIP) networks, which allow voice communications over the internet. In these networks, the IAM message is sent over a Session Initiation Protocol (SIP) trunk.

Conclusion

IAM is an essential message in telecommunication networks that initiates a call or session and provides critical information about the call to the network. It is the first message sent by the calling party's device and contains components such as the nature of connection indicators, calling party number, called party number, forward call indicators, and user-to-user information.

The IAM message is transmitted in a digital format using the ISDN User Part (ISUP) protocol and is sent over the Signaling System 7 (SS7) network or over a digital interface such as Primary Rate Interface (PRI) or a Session Initiation Protocol (SIP) trunk.