Timers - HPE FlexNetwork HSR6800 Configuration Manual

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Network-LSA—Originated for broadcast and NBMA networks by the Designated Router. This
LSA contains the list of routers connected to the network, and is flooded throughout a single
area only.
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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 AS (an inter-area route).
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Inter-Area-Router-LSA—Originated by ABRs and flooded throughout the LSA's associated
area. Each Inter-Area-Router-LSA describes a route to ASBR (Autonomous System Boundary
Router).
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AS-external-LSA—Originated by ASBRs, and flooded throughout the autonomous system
(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.
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NSSA-external-LSA—Originated by ASBRs in NSSAs (Not-So-Stubby Areas) and flooded
throughout the NSSAs only. NSSA LSAs describe routes to other ASs. A default route can be
described by an NSSA external LSA.
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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.
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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 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.

Timers

OSPFv3 includes the following timers:
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OSPFv3 packet timer
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LSA delay timer
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SPF timer
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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 given period, which is called a "dead
interval," it declares the peer as down.
After sending an LSA to its adjacency, a router waits for an acknowledgment from the adjacency. If
no response is received after the retransmission interval elapses, the router sends the LSA again.
The retransmission interval must be longer than the round-trip time of the LSA.
LSA delay timer
Each LSA has an age in the local link state database (LSDB) (incremented by one per second), but
an LSA does not age on transmission. You must add an LSA delay time into the age time before
transmission, which is important for low-speed networks.
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