ESCON CTC with shared and unshared channels
CNC CHPID 50 and CTC CHPID 51 in System A are shared by LP1A, LP2A, LP3A, and LP4A. All partitions in the figure participate in an any-to-any CTC configuration. No redundancy is provided. All the channel paths on System B are unshared. For recommendations for numbering CTC control units and devices to simplify CTC configurations, see the ESCON and FICON Channel-to-Channel Reference, SB10-7034.
Four CTC communications are defined between each LP except for LP4A, which has six connections to
each of the other LPs. See Figure 1.
Note: All shared CTC
examples within a single CPC exclude an LP from communicating with itself. This exclusion is
required for some subsystems (for example, XCF). Other subsystems might not have this restriction
and might support the communication of an LP with itself.
