A secure storage for an X.509v3 digital certificate is provided (301, 302). Ports of a first and second apparatus (101, 102) are mutually authenticated (303) by using 802.1X based authentication and 802.1AR certificates. Traffic types are divided (304, 305) by an operator-configurable selector function into user plane, control plane, synchronization plane, and management plane traffic types. For Ethernet transport a virtual port is created for each traffic type, and a different MACsec secure connectivity association is created for each virtual port. For Ethernet transport an operator-programmable security policy is maintained for each traffic type. For IP transport an IPsec security association is created for each traffic type, and an operator-programmable security policy is maintained for each security association. For IP transport, TLS support may be enabled for compatibility with network management traffic. A port is repeatedly re-authenticated by an operator-definable timer value.