Token Passing: IEEE802.5 standard
max token holding time: 10 ms, limiting frame length
- SD, ED mark start, end of packet
- AC: access control byte:
- token bit: value 0 means token can be seized, value 1 means data follows FC
- priority bits: priority of packet
- reservation bits: station can write these bits to prevent stations with lower priority packet from seizing token after token becomes free