16. LSDB overload protection in OSPF configuration experiment

1. Experimental Topology

2. Principle analysis

When the number of non-self-generated LSA in the LSDB of R2 reaches 3 (475% LSA 3), the neighbor relationship with the neighbor will be ignored in one minute (ignore-time 1), and the neighbor relationship will be ignored continuously for one minute, and then the neighbor relationship will be rebuilt. If the ignore-count is greater than 3, the neighbor relationship will be permanently ignored. During this period, if the neighbor relationship lasts for 2 minutes, then the ignore-conut will be cleared to zero.

3. Experimental configuration

R1 configuration

Interface Loopback1

Ip address 11.1.1.1 255.255.255.0

Interface Loopback2

Ip address 22.1.1.1 255.255.255.0

Interface Loopback3

Ip address 33.1.1.1 255.255.255.0

Interface Loopback4

Ip address 44.1.1.1 255.255.255.0

Interface Serial0/0

Ip address 12.1.1.1 255.255.255.0

Router ospf 110

Router-id 1.1.1.1

Network 11.1.1.0 0.0.0.255 area 1

Network 12.1.1.0 0.0.0.255 area 0

Network 22.1.1.0 0.0.0.255 area 1

Network 33.1.1.0 0.0.0.255 area 1

Network 44.1.1.0 0.0.0.255 area 1

R2 configuration

Interface Serial0/0

Ip address 12.1.1.2 255.255.255.0

Router ospf 110

Max-lsa 4 ignore-time 1 ignore-count 3 reset-time 2

Network 12.1.1.0 0.0.0.255 area 0

4. Experimental verification.

As you can see, when R2 detects that the number of non-self-generated LSA in the LSDB reaches 3 (4: 75% LSA 3), one minute later (ignore-time 1) ignores the neighbor relationship with the neighbor, and continues to ignore the neighbor relationship for one minute, and then rebuilds the neighbor relationship. After repeating for more than 3, that is, after the ignore-count is greater than 3, the neighbor relationship can no longer be seen.