📖 What is OSPF Dead Interval?
The amount of time an OSPF router will wait to receive a Hello packet from a neighbor before declaring that neighbor down.
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Sensei Says:
"By default, the Dead interval is exactly four times the Hello interval (e.g., 40 seconds on broadcast networks). If you change the Hello timer, the Dead timer adjusts automatically."
📚 Certification: Certified Network Associate (200-301)
🔑 What are the Key Concepts of OSPF Dead Interval?
- ▸ Neighbor timeout
- ▸ Four times hello interval (default)
- ▸ Triggers topology recalculation
🎯 How does OSPF Dead Interval appear on the 200-301 Exam?
Diagnosing network flapping caused by a dead interval that is too short for a congested link.
Adjusting timers on a slow link to prevent false neighbor drops.
❓ Frequently Asked Questions
What happens when the Dead interval expires?
The router declares the neighbor down, flushes its routes from the routing table, and floods new LSAs to notify the network.
Can I manually configure the Dead interval?
Yes, using the 'ip ospf dead-interval' command on the interface.
Related Terms from Certified Network Associate
Ansible
Transmission Control Protocol (TCP)
Default VLAN (VLAN 1)
Dynamic ARP Inspection (DAI)
Overlay Network
Static Route