H3C Technologies H3C S12500 Series Switches - Manual (Page 323)

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OSPFv3 LSA types
OSPFv3 sends routing information in LSAs, which, as defined in RFC 5340, have the following types:
• Router-LSA—Originated by all routers. This LSA describes the collected states of the router's
interfaces to an area. Flooded throughout a single area only.
• Network-LSA—Originated for broadcast and NBMA networks by the Designated Router. This LSA
contains the list of routers connected to the network. Flooded throughout a single area only.
• Inter-Area-Prefix-LSA—Originated by Area Border Routers (ABRs), and flooded throughout the
LSA's associated area. Each Inter-Area-Prefix-LSA describes a route with IPv6 address prefix to a
destination outside the area, yet still inside the Autonomous System (AS), which is an inter-area
route.
• Inter-Area-Router-LSA—Originated by ABRs and flooded throughout the LSA's associated area.
Each Inter-Area-Router-LSA describes a route to the Autonomous System Boundary Router (ASBR).
• AS-external-LSA—Originated by ASBRs, and flooded throughout the AS (except Stub and NSSA
areas). Each AS-external-LSA describes a route to another AS. A default route can be described by
an AS external LSA.
• NSSA-external-LSA—Originated by Not-So-Stubby Area (NSSA) ASBRs and flooded through the
NSSA area. Each NSSA-external-LSA describes a route to another AS. A default route outside the
AS can be described by an NSSA-external-LSA.
• Link-LSA—A router originates a separate Link-LSA for each attached link. Link-LSAs have link-local
flooding scope. Each Link-LSA describes the IPv6 address prefix of the link and Link-local address of
the router.
• Intra-Area-Prefix-LSA—Each Intra-Area-Prefix-LSA contains IPv6 prefix information on a router, stub
area, or transit area information, and has area flooding scope. It was introduced because
Router-LSAs and Network-LSAs contain no address information.
RFC 5187 defines the Grace-LSA. A Grace-LSA is generated by a Graceful Restart (GR) restarter at
reboot and transmitted on the local link. The restarter describes the cause and interval of the reboot in the
Grace-LSA to tell its neighbors that it performs a GR operation.
OSPFv3 timers
OSPFv3 include the following timers:
• OSPFv3 packet timer
• LSA delay timer
• SPF timer
• GR timer
OSPFv3 packet timer
Hello packets are sent periodically between neighboring routers for finding and maintaining neighbor
relationships, or for DR and BDR election. The hello interval must be identical on neighboring interfaces.
The smaller the hello interval, the faster the network convergence speed and the bigger the network load.
If a router receives no hello packet from a neighbor within a period, which is called a "dead interval,"
it will declare the peer is down.