Monday, January 20, 2014

OSPF Flooding Reduction


Pic. 1 - Topology Diagram.

Task 1
Remove OSPF configuration applied in the previous lab.

Task2
Point-to-point connection between R4 and R5 is slow. Disable the default LSA flooding triggered every 30 minutes in OSPF area 45.

Questions
Try to answer the following questions:
  1. What does RFC 2328 stipulate regarding the LSA MaxAge?
  2. What is common way to refer to OSPF flooding behavior?
Lab Solution

Solution configuration can be accessed below (if you want to save it, click the link, then go to File-->Download):
https://drive.google.com/file/d/0BwE5C95tpjZOSXFTSFhzMFZyQTg/edit?usp=sharing


Task 1
Remove OSPF configuration applied in the previous lab.

R4 Config:
!
interface Serial0/1
 no ip ospf demand-circuit
!

Task2
Point-to-point connection between R4 and R5 is slow. Disable the default LSA flooding triggered every 30 minutes in OSPF area 45.

R4 Config:
!
interface Serial0/1
 ip address 172.16.45.4 255.255.255.0
 ip ospf flood-reduction
!

R5 Config:
!
interface Serial0/1
 ip address 172.16.45.5 255.255.255.0
 ip ospf flood-reduction
!

Pic. 2 - OSPF Database on R5.



Study Drill

RFC 2328 (OSPF version2) defines the maximum age of LSA (MaxAge). The timer is set to 30 minutes by default after which LSAs time will not be incremented. An OSPF router mus re-flood this LSA as it is a new LSA. This behavior is called 'paranoid' update. This can be disabled using DoNotAge flag in OSPF update.