ask whether having their data travel wirelessly over long distances makes it more vulnerable to cybersecurity breaches. Once the data leaves the enterprise wired network and enters the 4G or 5G wireless network, it relies on the encryption of the wireless network. Let us look at the potential security risks of FMC. Overall, cybersecurity risks for mobile operators are on the rise. In July 2022, the French mobile operator La Poste Mobile experienced a ransomware attack. La Poste Mobile was a victim of the LockBit ransomware operation (see https : / cybersecurityworldconference.com/2022/07/10/french-telephone-operator- la-poste-mobile-suffered-a-ransomware-attack for more details). Since FMC depends on many protocols and technologies, such as SIP and UMA, it is dependent on the underlying security of those technologies. SIP security SIP is vulnerable to cybersecurity attacks if not properly secured. SIP security is based on the following: Authentication Confidentiality Other security functions Securing SIP requires a defense-in-depth strategy. Defense-in-depth This is a cybersecurity concept where several independent layers are used to strengthen overall security. National Institute of Standards and Technology (NIST) defines it as an "Information security strategy integrating people, technology, and operation capabilities to establish variable barriers across multiple layers and missions of the organization." Source:https://csrc.nist.gov/glossary/term/defense_in_depth Secure SIP is one way of securing SIP communication and was first described in SIP RFC 3261 (https://www.ietf.org/rfc/rfc3261.txt).This helps to secure the sending of SIP messages through a Transport Layer Security (TLS) encrypted channel. TLS is commonly used for the security of HTTP sessions. TLS can be used to protect SIP session communications. It can prevent eavesdropping or tampering with SIP messages. Hence, one way to secure SIP communication is to limit the use of SIP devices that support secure SIP. This will improve the overall security of 