Key server
The participants in an MKA instance agree on a key server and are responsible for the following:
deciding on the use of MACsec
cipher suite selection
SAK generation and distribution
SA assignment
identifying the CA when two or more CAs merge
Each participant in an MKA instance uses the key server priority (an 8-bit integer) encoded in each MKPDU to agree on the key server. Each participant selects the live participant advertising the highest priority as its key server whenever the live peers list changes, unless the highest-priority participant has selected another participant as its key server or is unwilling to act as the key server. If a key server cannot be selected, SAKs are not distributed. In the event of a tie for the highest-priority key server, the member with the highest-priority SCI is chosen. For consistency with other uses of the SCI MAC address component as a priority, numerically lower values of the key server priority and SCI are afforded the highest priority.