Describes maximum LSP lifetime values and refresh interval settings, clarifying how to configure and manage these parameters to ensure proper LSP operation and stability.
A maximum LSP lifetime and refresh interval are IS-IS protocol settings that
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determine how frequently the router refreshes link-state packets (LSPs) in the IS-IS database
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define how long LSPs remain valid in a device’s database before removal, and
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ensure routing stability by periodically refreshing LSPs and deleting outdated entries.
Default values
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By default, the router sends a periodic LSP refresh every 15 minutes.
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LSPs remain in the database for 20 minutes by default.
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If LSPs are not refreshed within their lifetime, they are deleted.
Configuration options
You can configure both the LSP refresh interval and the maximum lifetime.
Setting relationships
The refresh interval should always be less than the maximum lifetime; otherwise, LSPs might be deleted before they are refreshed.
Automatic adjustment
If no refresh interval is configured, the software automatically adjusts the interval as necessary to prevent premature LSP expiration.