How to configure two ISPs as floating static routes

[goyourmin]

 hello !

There are two ISPs. ISP-1 is the main route and ISP-2 is the backup path.(ISP - Router all eBGP)

Only Static Routing is available, and there are no other options.

I'm trying to use Floating Static Route to set the main route and backup route, but I'm asking if it's possible.

If these methods are not possible, are there any other alternatives?

- Router-1
ip route 0.0.0.0 0.0.0.0 100.100.100.1 (ISP-1 main)
ip route 0.0.0.0 0.0.0.0 200.200.200.1 20 (ISP-2 backup)

- Router-2
ip route 0.0.0.0 0.0.0.0 100.100.100.1 (ISP-1 main)
ip route 0.0.0.0 0.0.0.0 200.200.200.1 20 (ISP-2 backup)

Best regards,

[M02@rt37 · Accepted solution]

Hello @goyourmin,

sorry I don't understant and I need more clarification.

- Router-1
ip route 0.0.0.0 0.0.0.0 100.100.100.1 (ISP-1 main) ----- [1]
ip route 0.0.0.0 0.0.0.0 200.200.200.1 20 (ISP-2 backup) ----- [2]

How Router-1 should have IP ROUTE [2] because the next-hop 200.200.200.1 is not in its side!




It should be ip route 0.0.0.0 0.0.0.0 172.16.0.X 20 (ISP-2 backup towards Router-2)

Then on Router-1:

- Router-1
ip route 0.0.0.0 0.0.0.0 100.100.100.1 (ISP-1 main) 
ip route 0.0.0.0 0.0.0.0 172.16.0.X 20 20 (ISP-2 backup) 

And as concerned Router-2:

- Router-2
ip route 0.0.0.0 0.0.0.0 176.16.0.Y (ISP-1 main towards Router-1)
ip route 0.0.0.0 0.0.0.0 200.200.200.1 20 (ISP-2 backup)

-- You could add ipsla also to force the backup route if MAIN ISP is down.

[paul driver · Accepted solution]

M02@rt37  you would require IPSLA however given the topology presented it would be very adminstrative, best way would to introduce some dynamic routing

[M02@rt37]

Fore sure @paul driver., but "Only Static Routing is available, and there are no other options."

[goyourmin]

I'm sorry. Currently, dynamic routing configuration is not possible for a number of reasons.

[goyourmin]

I wondered if that was possible. now I understand that the static route is only available for

next-hops

Eventually, if ISP-1 fails, I understood that the usual thing I could do was to change the static configuration settings myself.

- Router-1 (Router-1 E0/0 172.16.0.1/30)
ip route 0.0.0.0 0.0.0.0 100.100.100.1 (ISP-1 main)
ip route 0.0.0.0 0.0.0.0 172.16.0.2 20 (ISP-2 backup)

- Router-2 (Router-2 E0/0 172.16.0.2/30)
ip route 0.0.0.0 0.0.0.0 176.16.0.1 (ISP-1 main towards Router-1)
ip route 0.0.0.0 0.0.0.0 200.200.200.1 20 (ISP-2 backup)hops.

[M02@rt37]

Correct  @goyourmin 

That's first step!

[paul driver]

Hello
Incorporating

iplsa

and object tracking would work for you regards the default statics, However looking at your topology are you not receiving a default from the upstream  ISPs?

Do you have IBGP between

rtr 1-2

if so it would be best to introduce some dynamic routing between your wan

rtrs

and the L3 switches (OSPF), and then advertise a default from the wan

rtrs

into your LAN with metrics, (the lower value best preferred) this will provide a more resilient, deterministic and dynamic failover?

[goyourmin]

It is assumed that ISP-1, 2 are different companies and communicate with each other via eBGP. In fact, even in the configuration, Router-1,2 and ISP companies work together with eBGP.