Network Computing is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Insider: 4-Gig's Successor Uncertain

Sales of 4-Gbit/s Fibre Channel gear are expected to dominate the SAN market for the next five years, but there is a bit of confusion about what will come next, according to the latest Byte and Switch Insider.

The report, 4-Gbit/s Fibre Channel SANs: A Market Update, maintains that the expected move to 8-Gbit/s Fibre Channel as a next step after 4-Gbit/s faces several roadblocks. First, there is a question about whether current standard copper-based twisted-pair cabling can handle the higher transmission rate over more than 25 meters. The move to 8-Gbit/s may require more expensive cabling, which would eliminate one of the biggest drivers of the current transition from 2-Gbit/s to 4-Gbit/s price parity.

"As with most types of cabling, the distance capability tends to decrease as the data transmission rate increases," research analyst Martin Courtney writes. "Single-mode fiber is well equipped to handle long distances, but the higher dispersion rate in thicker multimode fiber can cause problems. It is not yet clear if 8-Gbit/s transmissions can be extended to 100 meters without adding new transceivers, which is likely to push up the cost of 8-Gbit/s components."

Courtney also points out that transmission engineers and cabling standards bodies have time to work out a way to keep costs down. But that's not the only issue regarding a move to 8-Gbit/s Fibre Channel.

The report says the Fibre Channel Industry Association (FCIA) standards group is hedging its bets with two sets of specs. The Base2 Fibre Channel specs double the capacity each time, allowing the jump from 2- to 4- to 8-Gbit/s and so on, while remaining backward compatible. However, the FCIA also has a Base10 specification for 10-Gbit/s Fibre Channel and perhaps 20-Gbit/s down the road.

  • 1