Back to: FC (Fibre Channel) fundamentals
FC (Fibre Channel) data transfer can operate in three modes based on how data flows between devices:
1. Simplex Mode
- Data flows in only one direction at a time.
- There is no simultaneous transmission and reception.
- Typically used in one-way communication setups.
- Example: A unidirectional link where a sender transmits data, but the receiver does not send anything back.
2. Half-Duplex Mode
- Data can flow in both directions, but only one direction at a time.
- Devices take turns transmitting and receiving.
- Slower than full-duplex as it introduces waiting times for switching directions.
- Example: Walkie-talkies, where only one person speaks at a time.
3. Full-Duplex Mode
- Data flows in both directions simultaneously.
- Offers the highest efficiency as there is no waiting time.
- Most modern Fibre Channel networks use full-duplex mode to maximize performance.
- Example: A telephone conversation where both people can speak and listen at the same time.
FC and Duplex Modes in SAN
- Modern Fibre Channel SANs (Storage Area Networks) primarily operate in full-duplex mode, allowing high-speed data transfers with minimal latency.
- Full-duplex doubles the effective bandwidth since data is sent and received simultaneously over separate fibers.
- Older FC implementations or certain FC Arbitrated Loop (FC-AL) environments may use half-duplex due to protocol limitations.