Visara FEP-4600 Planning Guide - Manual (Page 18)

Chapter 1. FEP-4600 Overview
1-10 707117-003
Feature Compatibility
The FEP-4600 is capable of supporting all combinations of features through a single
ESCON or FICON interface, however the host itself may have difficulty mixing different
types of traffic. It is not recommended to mix PU2 and PU4 traffic over the same host
CHPID. When ESCON CHPIDs are attached directly to the FEP-4600 (no ESCON
director in use) then you must separate PU4 traffic from other traffic (PU2 or Non-SNA)
by using more than one ESCON interface. When you are using ESCON directors then
you can direct the traffic into the director through different CHPIDs, but have a single
ESCON out to the FEP-4600.