Verilink NCM 2000 (880-502623-001) Product Manual - Manual (Page 13)

NCM Overview
Verilink NCM 2000 1-3
NOTE: B ecause the database resides in the NCM module, an NCM moved to
a different node without having its database first cleared, will
reconfigure the new node. Take care not to cause unintended
configuration effects when swapping or moving NCMs.
Management
Redundancy
Two NCM modules may be placed in a node in order for one to
serve as a redundant backup for the other. The in-service NCM will
synchronize the database of all card configurations and circuits in
the standby NCM. If the primary NCM fails or is removed, the
standby NCM will take over management of the node using the
same MAC and IP addresses.
The primary NCM is the one with the greater running time and/or
in the lower numbered shelf and slot. NCMs must be able to
communicate with each other. If a standby NCM is in a different
shelf than the primary NCM, the shelves must be connected using
ACP-type daisy-chain cables. See
Figure 1-6 in the section “Daisy-
Chaining AS2000 Shelves”.
Figure 1-1 shows an application using two NCMs in a node and
three Node Manager software installations, all connected to an
Ethernet LAN.
NCM as a
Gateway
The primary NCM is responsible for managing all the slots within
the node. All communication between the NCM and the slots uses
the ACP or TABS bus. Additionally, the primary NCM acts as a
gateway for management traffic passing between the slots and the
optional Node Manager software package. Node Manager is a
Windows-based, SNMP-compatible network management program
that features a Graphical User Interface (GUI).
The primary and secondary NCMs communicate with each other. If
the primary NCM detects that there is no secondary NCM, the
primary NCM sets an alarm and then continues normal operations.
If the secondary NCM detects that there is no primary NCM, it
becomes the primary NCM. Every 15 minutes, the primary NCM
updates the database in the secondary NCM.