IEEE 802.1AEbw-2013 PDF
This amendment specifies the optional use of AES-128 (Advanced Encryption Standard-128) and AES-256 GCM (Galois Counter Mode) Cipher Suites that make use of a 64-bit PN (packet number) as part of their IV (Initialization Vector) parameter while retaining the existing MACsec (Media Access Control security) frame format by continuing to communicate only the least significant 32 bits of the PN in the SecTAG (security tag).
This standard specifies the optional use of Cipher Suites that make use of a 64-bit PN to allow more than 2**32 packets to be sent with a single Secure Association Key.
Amendment Standard – Superseded. The optional use of Cipher Suites that make use of a 64-bit (PN) to allow more than 232 MACsec protected frames to be sent with a single Secure Association Key are specified by this amendment.