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Guillaume ZussyFlag for France asked on

Does the BGP protocol provide solution for a default route redundancy system ?

Hello,

I've tested the command "ip sla". I've tracked objects to redirect a trafic either in a default route or another. But I'm wondering if another solution exists. A solution that use a BGP command or something else like that.

FAI
|
|
|
Router BGP
|
|
|                            WAN
6509 ----------------------------------- 6509

The 6509 has a default route to the BGP router. The BGP router has a default route to the FAI. If the route to the FAI is down, the trafic has to be redirected through the WAN link to another Internet connexion.

If the router BGP see that its route to the FAI is down, can he provides a "new" route for the trafic to be redirected through the WAN link ?
Or, another solution, BGP says to EIGRP : "My route is down, please redirect the traffic through the WAN". But in this case, does EIGRP provides a tools to do that ?

Thanks for your answers !

Networking Hardware-OtherRouters

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Guillaume Zussy

8/22/2022 - Mon
ASKER CERTIFIED SOLUTION
ngravatt

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ASKER
Guillaume Zussy

Thanks. Do you have a example of what you say ?

I don't know if this solution is really as simple as you says... And if it really works.

Because the primary route would be the next hop FAI. But the secondary route has to come back through the 6509 and the WAN to be redirected to the other connexion in the other site.
ngravatt

i assume the 6509 has a default route statement in it, right?

the 'router BGP' will inject that default route into your 6509, with an administrative distance of 200 and a weight of 0.

here is the output from my router:

B*   0.0.0.0/0 [200/0] via 206.xxx.xxx.4,

add a static route in your 6509 with an admin distance of 201

'You can modify the administrative distance of a protocol through the distance command in the routing process subconfiguration mode'

I ASSUME your ISP advertises the BGP default route to your 'router BGP' then it is advertised to your 6509?

check this by going into the 6509 and typing 'show ip route'
ASKER
Guillaume Zussy

In fact I have a firewall between the 6509 and the router BGP. The default route for the 6509 is the firewall. The BGP routing is static not dynamic.

But your solution seems to be good...
If we put the BGP routing dynamic, then we redistribute the BGP route into EIGRP. We put two different route in the 6509, 1 through BGP and 1 through the WAN with another weight. If the BGp route goes down, the 6509 know that and can redirect the traffic through the WAN.

But what about the firewall in the middle ?

Thanks for your help !
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ngravatt

hmmm.

firewalls are usually not supposed to be used as routers, so this may not work.  You may need to get one more router and put it between the firewall and the 2 BGP and WAN router.
ngravatt

read this, i just found it:

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a008009487d.shtml

its an article on how to connect two ISPs through a Cisco Firewall.

ASKER
Guillaume Zussy

I will study your solution with two routes. But don't you think that the two different routes with two different metrics will provide load balancing ? Because, I don't want this thing. I want to have "active/passive" default route.
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ASKER
Guillaume Zussy

Will two different routes with two different metrics provide load balancing ? Or, "active/passive" route.

Thanks for your response.
ASKER
Guillaume Zussy

I've tested 2 default route with 2 metrics. This does not provide load balancing. It's a failover configuration.

Thanks for your help.
ASKER
Guillaume Zussy

Thanks for your help
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