topic Re: Does floating static route really goes with dynamic routing? in Routing and SD-WAN

Does floating static route really goes with dynamic routing?

MikeNY85 — Mon, 06 Mar 2023 18:14:26 GMT

Hello professionals,

My question is "why would we configure a floating static route, if we already using a dynamic routing protocol in the network"?. isn't the dynamic routing protocol has the capability to calculate an alternate path in case of link failure?. Of course, a floating static route works best with static routing.. I am just not convinced with the fact that floating static route works also with dynamic routing.

Any help would be much appreciated..

Thanks in advance!

Re: Does floating static route really goes with dynamic routing?

MHM Cisco World — Mon, 06 Mar 2023 20:53:09 GMT

you have Edge router and dual ISP
and you need routing
you can not run routing because not always the ISP side accept run routing with costumer
so the solution is Static route
and if you have dual ISP link then you need floating static route for failover.

so you run routing protocol inside your network and config static between your edge router and ISP.

Re: Does floating static route really goes with dynamic routing?

balaji.bandi — Mon, 06 Mar 2023 19:38:26 GMT

"why would we configure a floating static route, if we already using a dynamic routing protocol in the network"? - Sure its all depends how you configured and use case.

if this not so big network and not many routers in place , simple static routing works.

Re: Does floating static route really goes with dynamic routing?

David Ruess — Mon, 06 Mar 2023 20:45:26 GMT

Hello,

With your specific question a scenario could be you lose your OSPF/EIGRP neighborship (for any of 1000 reasons) but still maintain connectivity. Your floating static route (usually default route) will kick in and at least forward most of your traffic out of your network, or wherever your floating static route points.

Is it likely to happen especially with redundancy, probably not. But its also not hurting anything or really taking up resources as it wont be in use unless that scenario happened.

Reasons you can lose neigborship:

-Key rotation (authentication) misconfigured or not enough overlap

-Misconfiguration change on ISP side

-Change in routing table (network/router churn)

-Jr engineer not fully understanding some configurations (personal experience)

And many more.

-David

Re: Does floating static route really goes with dynamic routing?

Joseph W. Doherty — Mon, 06 Mar 2023 21:13:01 GMT

Possibly the most likely situation where you might see both dynamic routing and static routing especially with a floating static is a case like @MHM Cisco World described.

Basically any case where the "other side" will not or can not do dynamic routing with you.

Re: Does floating static route really goes with dynamic routing?

MikeNY85 — Mon, 06 Mar 2023 23:09:03 GMT

@MHM Cisco World I really appreciate your help a lot and thanks very very very much for your response. It's always good to learn from real world examples and professionals like you!.

Re: Does floating static route really goes with dynamic routing?

MikeNY85 — Mon, 06 Mar 2023 23:13:17 GMT

@David Ruess thanks very much David for you answer and I really appreciate it.

Re: Does floating static route really goes with dynamic routing?

MHM Cisco World — Mon, 06 Mar 2023 23:16:34 GMT

You are so so welcome