Brocade Communications Systems ICX 7250 series, Руководство по настройке

Страница: 246 / 483

If the router is an ABR, you can prevent any type 3 and type 4 LSA from being injected into the area. The only exception is that a default
route is injected into the NSSA by the ABR, and strictly as a type 3 LSA.
LSA types for OSPFv3
Communication among OSPFv3 areas is provided by means of link-state advertisements (LSAs). OSPFv3 supports a number of types
of LSAs:
• Router LSAs (Type 1)
• Network LSAs (Type 2)
• Interarea-prefix LSAs for ABRs (Type 3)
• Interarea-router LSAs for ASBRs (Type 4)
• Autonomous system External LSAs (Type 5)
• Group Membership LSAs (Type 6)
• NSSA External LSAs (Type 7)
• Link LSAs (Type 8)
• Intra-area-prefix LSAs (Type 9)
For more information about these LSAs, refer to RFC 5340.
Virtual links
All ABRs must have either a direct or indirect link to an OSPFv3 backbone area (0 or 0.0.0.0). If an ABR does not have a physical link to
a backbone area, you can configure a virtual link from the ABR to another router within the same area that has a physical connection to
the backbone area.
The path for a virtual link is through an area shared by the neighbor ABR (router with a physical backbone connection) and the ABR
requiring a logical connection to the backbone.
In the following figure, a virtual link has been created between ABR1 and ABR2. ABR1 has a direct link to the backbone area, while
ABR2 has an indirect link to the backbone area through Area 1.
Virtual links
Brocade FastIron Layer 3 Routing Configuration Guide
246 53-1003903-04