An important goal is to avoid isolating any nodes when provisioning area addresses and Level 2 routers remotely. Isolating a node may require craft dispatch to the isolated node to recover. To avoid isolating nodes, the sequence for remote provisioning is established with respect to the local node to which the WaveStar® CIT is connected or the TL1–GNE through which OMS is connected. Typically, the local node or TL1–GNE 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 or TL1–GNE are provisioned first.
Work back toward the local node or TL1–GNE's sub-tending ring.
If OMS is part of the network via an OSI LAN or WAN interface, provision the area address for the OMS.
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.
Both DRI and dual-homed rings are designed to protect against a failure of an interconnecting facility or a failure of the node at which the interconnection occurs. The choice of DRI or dual-homing is driven by the network topology. To provide protection when connecting between two UPSRs, use DRI. To provide protection when connecting between a UPSR and a single NE, use dual homing.
Another important goal is to provision the network in such a way that OSI communications disruption is minimized. Changing a node's area address and/or enabling a node as a Level 2 router causes the node to reset its controller. The reset is immediate and is part of the completion of the command. In addition to temporarily disrupting OSI communications, controller resets temporarily disable automatic transmission protection switching.
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.
Changing a node's area address and enabling a node as a Level 2 router, if appropriate, should usually both be done with a single command per node.
| November 2011 | Copyright © 2011 Alcatel-Lucent. All rights reserved. |