Supplemental flow control mechanisms are provided to facilitate efficient data exchange between Fibre Channel ports over extended distances. In one implementation, a supplemental buffer mechanism is maintained and managed in part by substituting a locally generated ready indication signal for the remotely generated ready indication signal provided by the Fibre Channel standard. In this way, data flow may be adjusted optimally irrespective of the relatively long propagation time of the ready signals exchanged by the two sides of the link.