RIP timers and reality, #3 (HOLDDOWN again)

We’re now going to test a different topology introduced at the end of article #2.

We are now going to test the HOLDDOWN timer of RIP when the backup router send a route with a metric higher than the primary router.

In this series of tests, we’ll see if the HOLDDOWN works in case the route disappears of R100 because of HOLDDOWN timer. Next time, we’ll see if it disappear if R101 advertises a metric 16 for NETWORK.

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RIP timers and reality, #1 (INVALID and FLUSH)

Short article about what really happens with RIP timers. I’ve run some tests putting in situation network advertisements for downlinks and how and when timers react.

The different tests are given in the form of timelines, with the action and reaction at the minute planned. Between brackets you’ll find what should have happened if one of the previous actions was not triggered.

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Cisco IP unnumbered inside

What is IP unnumbered?

In Cisco routers, the ip unnumbered <other_interface> command allows you to borrow the IP address of another interface.

Although the Cisco help page explains in detail how to do it, and to some extent the reasons to do so, let’s go deeper and explain the real howto.

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