Redistribution between different or same routing protocols can become a nasty thing when there are 2 or more redistribution points.

In this quiz, I present you the following scenario with redistribution between 2 different OSPF processes on 2 routers (R1 and R2) - see below diagram and configuration:


Although, at first glance, everything looks ok, this scenario poses some problems. Try to think of the problems from the perspective of Net A (
Then reveal the hints below to understand when the problem will come to the surface:

At some moment in time you'll notice that R1 is reaching Net A via the bottom OSPF Area:


Type escape sequence to abort.
Tracing the route to

  1 20 msec 44 msec 16 msec
  2 40 msec 56 msec 20 msec

Why does R1 prefers R2 to reach Net A (lo1 on R3)?

The cable connected to Fa0/0 on R3 gets unplugged. At this moment there is a routing loop in your network:


Type escape sequence to abort.
Tracing the route to

  1 68 msec 20 msec 20 msec
  2 36 msec 48 msec 32 msec
  3 52 msec 32 msec 20 msec
  4 20 msec 56 msec 52 msec
  5 40 msec 60 msec 52 msec
  6 108 msec 44 msec 68 msec
  7 68 msec 96 msec 68 msec  ...and so on...

How would you solve this problem?

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