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BGP Failover concern

Sravan Bhargav
Level 1
Level 1

Hi,

We have a situation here. We need to configure BGP fail-over. We have two ISP links (ISP1 & ISP2) from two different locations which is connected to our remote site.

And we have already configured BGP on remote site with another ISP(ISP3). AS is 1. Is it possible to configure BGP fail over for the above situation on our router 3845.

Please revert back if you need any further info from myside.                   

Thanks,

Sravan

10 Replies 10

Sravan Bhargav
Level 1
Level 1

Really I need help on this....:(

Is it possible??? Is there any fluctuations on network??? because this should be carried out in prod network.

Hi Sravan

Would be really great help, if you can explain your scenarion in details, here are you talking about BGP Fall-over or some bgp fail-over scenario ?

Regards,

Sandip

Hi Sandip,

I'm talking about bgp fail-over scenario.

We are having three locations. A, B and C(remote site).

We are getting routes from A(ISP1) loaction and B(ISP2) location on C location router. BGP Failover should be configured on C. All of them are having internal AS 1. All Provider IP's are private series.

And we have already configured BGP on remote site with another ISP(ISP3).

Let me know if you want any additional information from me.

Thanks,

Sravan

Hi Sravan,

is the remote site directly connected or providing a layer two circuit? In this case you could simply use BFD. very easy to configure , reliable and very fast to detect failures. BFD will register the above protocols (BGP in your case) with the bgp fall-over bfd command.

If you described how you are connected to remote site (P2P, layer 2 circuit, X AS far away neighbor etc..) we could help more. BFD is the way to go if the scenario will let you.

Alessio

      

PS: if not feasible BFD (best choice ) go and read this: https://supportforums.cisco.com/thread/43354

Hi Sravan,

If I understood correctly, you are receiving same routes on Location C from Location A & B, and you want some mechanisam on Location C in case of failure of Location A or B, correct ?

If this is the case, I am assuming you are receving same routes from both location A and B on Location C

For example you are advertising 10/24 from Location A and Location to Location C

Now, you need to tune BGP parameter to make one of the Location is prefered.

On Location C router, you can use LP for outgoing traffic or any other attribut like MED or AS Path Prepend for Incoming traffic.

By doing this your one of the location will be preferred, and once preferred location goes down, traffic will automatically switchover to secondary location

One thing you need to make sure on Router C, you must see prefxes in BGP table from both Location A and B.

For fast failover you can use BFD or tune BGP timers etc.

Please let me know if you need more information

Regards,

Sandip

Hi Alessio,

All 3 links are point to point links which is connected to remote site.

Thanks,

Sravan


Hi Sandip,

My Requirement is when ISP3 to the remote site(C) is down. Either of ISP1 from location A or location B ISP2 should go up. For that I want to configure BGP on remote site. Will it possible?

Thanks,

Sravan

Hi Sravan

It would be great, if you can explain your current scenario in details with diagram / topology and what you need ?

Regards,

Sandip

Hi Sandip,

Sure I'll be sending you the topology within 2 days. Please give me some time :-(

And sorry for delayed reply..kind of busy with migration :-)

Thanks.