What causes route flapping?

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Keyon Marks asked a question: What causes route flapping?
Asked By: Keyon Marks
Date created: Sun, Jun 6, 2021 5:37 AM
Date updated: Thu, Jun 30, 2022 5:45 PM

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Top best answers to the question «What causes route flapping»

Route flapping is caused by pathological conditions (hardware errors, software errors, configuration errors, intermittent errors in communications links, unreliable connections, etc.) ... within the network which cause certain reachability information to be repeatedly advertised and withdrawn.

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The major reasons for route flap are: Hardware errors Software errors Configuration errors (such as misconfigured Channel Service Units) Intermittent errors in communications links Unreliable connections

Route flapping is caused by pathological conditions (hardware errors, software errors, configuration errors, intermittent errors in communications links, unreliable connections, etc.) within the network which cause certain reachability information to be repeatedly advertised and withdrawn.

Route flapping occurs when a router interface alternates rapidly between the up and down states and it can cripple a router with excessive updates and recalculations. However, the summarization configuration prevents the RTC route flapping from affecting any other routers.

This document describes how to troubleshoot flapping Border Gateway Protocol (BGP) routes caused by recursive routing failure. Common symptoms of recursive routing failure in BGP are: Constant deletion and reinsertion of BGP routes into the routing table. Loss of connectivity towards destinations learned through BGP.

Route flapping. Route flapping is caused by pathological conditions (hardware errors, software errors, configuration errors, intermittent errors in communications links, unreliable connections, etc.) within the network which cause certain reachability information to be repeatedly advertised and withdrawn.

Route flapping happens when there are pathological conditions such as hardware, software or configuration errors found in the network that causes certain information to be repeatedly advertised and withdrawn.

When the route timer in the routing table always shows 00:00:00, it doesn't necessarily mean that the router is constantly taking the route out and reinstalling it. It simply means that one of the router's neighbors is constantly updating the router with the route. The neighbor updating the route is not necessarily the best path to the route, but it is one possible path.

What Causes Recursive Routing Failure? These steps describe the cause of recursive routing failures: Refer to the configuration of Rtr-A. In this configuration, a static route 20.20.20.0/24 is configured pointing to the directly connected next-hop 192.168.16.2. With this static route, a BGP session with peer Rtr-B 20.20.20.20 is established.

Also, it would be helpful if you could provide the output of show ip eigrp neighbor and show ip eigrp neighbor detail commands some 10-20 seconds after the neighbors flap and come back up - from both the router and the ASA. It is possible that the flaps are caused by STP topology changes in your network.

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