Extreme Networks ExtremeWare XOS 11.1, Руководство пользователя

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Overview of OSPF
ExtremeWare XOS 11.1 Concepts Guide
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Database Overflow
The OSPF database overflow feature allows you to limit the size of the LSDB and to maintain a
consistent LSDB across all the routers in the domain, which ensures that all routers have a consistent
view of the network.
Consistency is achieved by:
●
Limiting the number of external LSAs in the database of each router.
●
Ensuring that all routers have identical LSAs.
To configure OSPF database overflow, use the following command:
configure ospf ase-limit <number> {timeout <seconds>}
where:
●
<number>
—Specifies the number of external LSAs that the system supports before it goes into
overflow state. A limit value of zero disables the functionality.
When the LSDB size limit is reached, OSPF database overflow flushes LSAs from the LSDB. OSPF
database overflow flushes the same LSAs from all the routers, which maintains consistency.
●
timeout
—Specifies the timeout, in seconds, after which the system ceases to be in overflow state. A
timeout value of zero leaves the system in overflow state until OSPF is disabled and re-enabled.
Opaque LSAs
Opaque LSAs are a generic OSPF mechanism used to carry auxiliary information in the OSPF database.
Opaque LSAs are most commonly used to support OSPF traffic engineering.
Normally, support for opaque LSAs is autonegotiated between OSPF neighbors. In the event that you
experience interoperability problems, you can disable opaque LSAs across the entire system using the
following command:
disable ospf capability opaque-lsa
To re-enable opaque LSAs across the entire system, use the following command:
enable ospf capability opaque-lsa
If your network uses opaque LSAs, Extreme Networks recommends that all routers on your OSPF
network support opaque LSAs. Routers that do not support opaque LSAs do not store or flood them. At
minimum a well interconnected subsection of your OSPF network must support opaque LSAs to
maintain reliability of their transmission.
10 Area scoping—Opaque
11 AS scoping—Opaque
Table 51: LSA type numbers (Continued)
Type Number Description