WAN link fail-over

[Debabrata Majhi]

We have a two link which is terminated in two different router in branch.Now we want to do fail over between two link.Both the link is running BGP

One link will be act as primary.Once the primary link goes down entire local traffic will shift to Link2.

Can any one share suggestion

[ulrickfr2001]

Set local-preference of the first link higher than the second one to influence outband traffic and use as-path prepend on second link to influence inbound traffic (assuming the provider is not changing the attribute). And then apply iBGP between both branch routers.

[Debabrata Majhi]

Hi

Thanks.

Local branch end HSRP is running.Can we use weight attribute to fulfill our requirement

awaiting for your response

thanks

[ulrickfr2001]

Yes you can use weight but is not recommanded because it will only influence routes on the router where the weight is set. The secondary router will not know about the weight set in the primary router. So you will need to configure the weight on each router then. But you still need iBGP between both routers.

[ParthaSarathi]

When  We talk of traffic diversion we have to take two  things into account inbound /outbound  For inbound  MED / As path prepending is the best way . Talking about outbound , its highly depends on the technology we are using .If  you have both the router connected to l2 switch hsrp is the best option . If you  have l3 device there on LAN and using IGP such as ospf,  eigrp  and  doing  mutual redistribution  , you can influence outbound traffic by manipulating redistribution  metric . All last but not the least if u are using iBGP  towards LAN local preference  is the best option .

[Debabrata Majhi]

Hi Parha

Thanks for guideline.

I need some clarification

Scenario is-Both the router is connected on L2 mode and HSRP is running.Now suppose In DC end Both the link up and working.Now I want to shift traffic manualy from branch through link2(Consider link1 is primary).What will be the best option for me to configure the router in BGP

Thanks in advance

[ulrickfr2001 · Accepted solution]

Hi Debabrata,

As Partha said you need to clarify which traffic you want to shift. Because in BGP traffic engineering is separate when you want to influence inbound or outbound traffic.
If you talk about inbound traffic, you need to discuss it with your Service Provider.

Assuming you are talking about outbound, as you are using HSRP and both Links are UP and running, no need to configure BGP. Just modify the hsrp configuration (setting higher priority on link2 router and activate preempt for example) will do the stuff.