AT&T 7300 series, 7500 series, 7100 series, 2500 series manual Distributed Communications System DCS

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 6-5shows 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.