What is SS7 protocol

Some information about the SS7 protocol:

  1. SS7 was developed in the 1980s by the International Telecommunication Union (ITU) and is now widely used in telephone and cellular networks around the world.
  2. SS7 operates at the network layer of the OSI model and uses out-of-band signaling, which means that it uses a separate network connection from the voice or data traffic. This allows the SS7 signaling traffic to be handled independently from the voice or data traffic, making it more reliable and efficient.
  3. The SS7 protocol defines a variety of messages that are used to control and manage calls and other network services. These messages include, but are not limited to, the following:
    • IAM (Initial Address Message): Used to initiate a call setup between two network elements.
    • ACM (Address Complete Message): Sent by the terminating switch to indicate that it is ready to connect the call to the destination number.
    • ANM (Answer Message): Sent by the terminating switch to indicate that the call has been answered.
    • REL (Release Message): Sent by either party to terminate the call.
    • CPG (Call Progress Message): Used to provide call progress information to the calling party, such as ring-back tones and busy signals.
  4. SS7 is considered to be a secure protocol, but it has been subject to security vulnerabilities and attacks in recent years. These vulnerabilities have been exploited by hackers to perform various types of attacks, such as eavesdropping on calls, intercepting SMS messages, and even remotely controlling cellular devices.
  5. In response to these security concerns, the telecommunications industry has been working to implement new security measures, such as firewalls, intrusion detection systems, and encryption, to protect against SS7-based attacks.

Overall, the SS7 protocol is an important and widely used technology in modern telecommunications networks. Despite some security concerns, it remains a critical component in enabling the reliable and efficient routing of calls and other network services.

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