Alcatel-Lucent 1643 AMS User's Operation Manual page 98

Management communication setup
Routing management data
The following scenario describes routing management data in a divisioned network.
Suppose a node A wants to send messages to another node. If this node is in its own
area (determined by the Area Id part in the Area Address field), the messages from A
to this particular node (B) are routed directly using the Level 1 Intermediate System.
(See previous figure)
Alternatively, if the required destination is in a different area (C), the messages are sent
to a second, higher level (Level 2) Intermediate System. This Intermediate System
routes the messages coming from node A to other Level 2 Intermediate Systems until
they reach a Level 2 Intermediate System attached to the destination area of C. From
there it is routed within the area using Level 1 Intermediate Systems to node C.
Notice that in both of the above cases the ES-ES communication between nodes in the
same or in different areas is still possible.
OSI-DCN networks types
In general the OSI-DCN network can be classified in three types:
• Undivided
• IS-IS Clustered
• IS-IS Area Divided network
The three types are illustrated in the figure below:
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4-8 Alcatel-Lucent - Proprietary
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DCN configurations
365-312-807R7.2
Issue 4, May 2007