Ospf Area Attribute Configuration; Configuring Ospf Area Attributes - Huawei Quidway S3900 Series Operation Manual

Operation Manual – Routing Protocol
Quidway S3900 Series Ethernet Switches-Release 1510
Note:
The ID of an OSPF process or OSPF multi-instance is unique. That is, the ID of
OSPF multi-instance must be different from any in-use process ID.
One segment can belong to only one area and you must specify each OSPF
interface to belong to a particular area.

4.4 OSPF Area Attribute Configuration

Area partition in OSPF reduces the number of LSAs in the network and enhances
OSPF scalability. To further reduce routing table size and the number of LSAs in some
non-backbone areas on the edge of the AS, you can configure these areas as stub
areas.
A stub area cannot import any external route. For this reason the concept of NSSA
area is introduced. Type7 LSAs can be advertised in an NSSA area. Type7 LSAs are
generated by ASBRs of the NSSA area, and will be transformed into AS-external
LSAs whey reaching ABRs in the NSSA area, which will then be advertised to other
areas.
After area partition, the OSPF route updates between non-backbone areas are
exchanged by way of the backbone area. Therefore, OSPF requires that all the
non-backbone areas should keep connectivity with the backbone area and the
backbone area must keep connectivity in itself.
If the physical connectivity cannot be ensured due to various restrictions, you can
configure OSPF virtual links to satisfy this requirement.
4.4.1 Configuration Prerequisites
Before configuring OSPF area attributes, perform the following tasks:
Configuring the network layer addresses of interfaces so that the adjacent nodes
are reachable to each other at the network layer
Performing basic OSPF configuration

4.4.2 Configuring OSPF Area Attributes

Table 4-3 Configure OSPF area attributes
Enter system view
Enter OSPF view
Enter OSPF area view
Operation
Huawei Technologies Proprietary
Command
system-view
ospf [ process-id
[ router-id router-id ] ]
area area-id
4-12
Chapter 4 OSPF Configuration
Description
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