AT&T DEFINITY 7200 series - Manual (Page 125)

DISTRIBUTED COMMUNICATIONS SYSTEM (DCS) 6-7
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Figure 6-5. DCIU/PI Linkage in a DCS Cluster
Mixed Link Connections. In reality, most DCS clusters exhibit both direct and minimized linkage. Figure
6-5 shows the signaling links for a 12-switch DCS configuration. This cluster uses some nondirect
signaling links. When a DCIU/PI message (packet) routes through a nondirect signaling link, it hops
through an intermediate node DCIU or PI before reaching its final destination. For example, to send a
message from node C to node L, the message hops through either node J or node K. Each signaling link
has software-assigned logical channels that define the message path (virtual circuit) and make nondirect
paths possible. Every node has a signaling path to every other node with a maximum of two hops in any
signaling path.