> What worries me is the situation which I've been working on, where > we want access to the PCS PHYs, and we can't have the PCS PHYs > represented as a phylib PHY because we may have a copper PHY behind > the PCS PHY, and we want to be talking to the copper PHY in the > first instance (the PCS PHY effectivel ybecomes a slave to the > copper PHY.) I guess we need to clarify what KR actually means. If we have a backplane with a MAC on each end, i think modelling it as a PHY could work. If however, we have a MAC connected to a backplane, and on the end of the backplane is a traditional PHY, or an SFP cage, we have problems. As your point out, we cannot have two PHYs in a chain for one MAC. But i agree with Russell. We need a general solution of how we deal with PCSs. Andrew