3. Extended sequence numbers may be supported. For compatibility with earlier 3GPP it shall be possible to communicate with nodes supporting RFC-2406. See annex E of TS33.210 for main differences. ESP encryption transforms and authentication algorithms marked with "MUST" in RFC 8221 shall be followed. AES-GMAC with AES-128 shall be supported. NULL authentication algorithm is explicitly not allowed for use unless an authenticated encryption algorithm is used. Where random values are needed, RFC 4086 shall be used as guidelines for hardware and software pseudorandom number generators. Internet Key Exchange protocol IKEv2 shall be supported for negotiation of IPsec SAs as defined by RFC 7296 and RFC 6311. For IKE_SA_INIT exchange Following algorithms shall be supported: Confidentiality: AES-GCM with a 16 octet ICV with 128-bit key length Pseudo-random function: PRF_HMAC_SHA2_256 Integrity: AUTH_HMAC_SHA256_128 Diffie-Hellman group 19 (256-bit random ECP group) Following algorithms should be supported: Confidentiality: AES-GCM with a 16 octet ICV with 256-bit key length Pseudo-random function: PRF_HMAC_SHA2_384 Diffie-Hellman group 20 (384-bit random ECP group) For IKE_AUTH exchange: Authentication method 2-Shared Key Message Integrity Code shall be supported. IP addresses and Fully Qualified Domain Names shall be supported for identification. Re-keying of IPsec SAs and IKE SAs shall be supported as specified in RFC. In addition to the requirements defined in RFC 7296, rekeying shall not lead to a noticeable degradation of service. For the CREATE_CHILD_SA - exchange A DH key exchange should be used, and the session keys should be changed frequently. For reauthentication Reauthentication of IKE SAs as specified in RFC 7296 Section 2.8.3 shall be supported. An Network Element (NE) shall proactively initiate reauthentication of IKE SAs, and creation of its Child SAs, that is, the new SAs shall be established before the old ones expire. Chapter 5 System software An NE shall destroy an IKE SA and its Child SAs when the au