Nokia's Session Border Controller (SBC) plays a crucial role in safeguarding signaling and control media as they traverse the boundaries of the IMS network. Positioned at the access network edges, it secures various forms of IP access while facilitating the delivery of all IMS services effectively. Additionally, it is located on the periphery of peering networks, enabling seamless roaming, IMS interconnection, and corporate SIP trunking operations. The SBC encompasses a range of functions, including the encryption and decryption of bearer traffic, firewall capabilities, and topology hiding for enhanced security, as well as media handling, transcoding, SIP interworking, and NAT traversal. It may be implemented as an independent SBC or integrated into Nokia’s VoLTE/VoWiFi framework. For VoIP services aimed at residential and enterprise customers, the SBC is equipped with robust protections against DoS/DDoS attacks, ensures network topology concealment from access points, facilitates NAT traversal, and supports various codecs, notably G.729, G.722, and T.38 Fax. Furthermore, within a VoLTE core network, it regulates access and supports mobility features, offering an EVS codec and compatibility with eSRVCC, VoWiFi, NPLI, S8HR roaming, and additional functionalities, thus enhancing the overall communication experience.