Users Guide

Type 11—Grace
LSA (OSPFv3)
Link-local opaque LSA for OSPFv3 only is sent during a graceful restart by an OSPFv3 router.
The LSA header is common to LSA types. Its size is 20 bytes. One of the fields of the LSA header is the link-state ID. Each
router link is defined as one of four types—type 1, 2, 3, or 4. The LSA includes a link ID field that identifies the object this link
connects to, by the network number and mask. Depending on the type, the link ID has different meanings.
1 Point-to-point connection to another router or neighboring router
2 Connection to a transit network IP address of the DR
3 Connection to a stub network IP network or subnet number
4 Virtual link neighboring router ID
Router priority
Router priority determines the designated router for the network. The default router priority is 1. When two routers attach to a
network, both attempt to become the DR. The router with the higher router priority takes precedence. If there is a tie, the
router with the higher router ID takes precedence. A router with a router priority set to zero cannot become the DR or BDR.
If not assigned, the system selects the router with the highest priority as the DR. The second highest priority is the BDR.
Priority rates from 0 to 255, with 255 as the highest number with the highest priority.
OSPF route limit
OS10 supports up to 16,000 OSPF routes. Within this range, the only restriction is on intra-area routes that scale only up to
1000 routes. Other OSPF routes can scale up to 16 K.
Shortest path first throttling
Use shortest path first (SPF) throttling to delay SPF calculations during periods of network instability. In an OSPF network, a
topology change event triggers an SPF calculation that is performed after a start time. When the start timer finishes, a hold
time can delay the next SPF calculation for an additional time.
When the hold timer is running:
● Each time a topology change occurs, the SPF calculation delays for double the configured hold time up to maximum wait
time.
● If no topology change occurs, an SPF calculation is performed and the hold timer is reset to its configured value.
Set the start, hold, and wait timers according to the stability of the OSPF network topology. Enter the values in milliseconds
(ms). If you do not specify a start-time, hold-time, or max-wait value, the default values are used.
OSPFv2 and OSPFv3 instances support SPF throttling. By default, SPF timers are disabled in an OSPF instance. Enter the no
version of this command to remove the configured SPF timers and disable SPF throttling.
Layer 3
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