Avoid isolating any nodes when provisioning area addresses and Level 2 routers remotely. It may be necessary to dispatch a craft technician to recover an isolated node.
To avoid isolating nodes, a sequence for remote provisioning is established with respect to the local node to which the WaveStar® CIT is connected. Typically, the local node is provisioned to be a Level 2 router first, but its area address is not changed initially. This general sequence can be modified in networks with redundant OSI LAN or DCC connectivity between and within areas.
The nodes and sub-tending rings that are furthest away from this local node are provisioned first.
Work back toward the local node's sub-tending ring.
Provision the local node's sub-tending ring.
Provision the local node last.
Important!
Before assigning area addresses and Level 2 routers in a network, be sure no alarms (especially DCC failure alarms) exist; otherwise, even the recommended remote provisioning sequence might result in isolated nodes. To confirm the network alarm status, it is recommended that a centralized maintenance center with TL1 OS support be consulted.
Always provision new area addresses for a sub-tending ring by starting with a node that is adjacent to the node that connects this sub-tending ring to the rest of the network, and then provision the area address for each sequential adjacent node going around the sub-tending ring. Provision the area address of the connecting node last, especially if the connecting node supports multiple sub-tending rings.
For single-homed sub-tending rings, provision the node that will be the Level 2 router node last; otherwise, nodes in its area could be isolated. For dual-homed rings, provision one of the nodes that will be Level 2 router first, so that OSI connectivity is established with provisioned nodes as soon as they complete their controller resets.
Another important goal is to provision the network in such a way that OSI communications disruption is minimized. Changing a node's area address or enabling a node as a Level 2 router causes the node to reset its controller. The reset is immediate upon completion of the command. In addition to temporarily disrupting OSI communications, controller resets temporarily disable automatic transmission protection switching.
If a node's area address and Level 2 routing status are both being changed, both changes should be made with a single command.
As one node is undergoing a controller reset in an area, the next adjacent node should be provisioned to minimize the overall time required to provision the nodes in an area and minimize the time that OSI communications with the nodes in the area are lost.
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