Verilink AS2000: The Basics (880-502981-001) Product Manual - Manual (Page 20)

System Information
2-4 Verilink Access System 2000: The Basics
ACP Controller
Bus Structure
The ACP can operate on either Data Bus A or C. The MLS 2200
provides up to five islands using bus segments A1-A5, or full shelf
control using bus C. Additionally, you can set up one or two self-
controlled islands on the MLS 2200 A bus, and have the remaining
segments under common control using the C bus. Refer to
Figure
2-3 .
The MLS 2000, QLS 2500, and DLS 2100 can use Bus A or C to
control all the ACP-based modules in the shelf. The ACP controller
bus can be expanded to other shelves with a daisy-chain cable
between the primary and expansion management ports.
Figure 2-3 MLS 2200 Controller Bus Usage
Shelf and Node
Masters
In an ACP-based node, a shelf master uses the ACP controller bus to
poll the other modules in the shelf for configuration and
performance status information. A redundant NCM in the same
shelf becomes the shelf master if the current shelf master fails. If
there is no redundant NCM in the shelf, an ACP application module
in the shelf becomes the shelf master if the NCM fails.
In a multi-shelf node, when the shelf master is polled by the node
master, it transfers the information from its shelf modules to the
node master. If the node master fails, the shelf master with the