Help with BGP

[Shibu1978]

Dear All,

I am trying to configure BGP on the attached design( first time i am in to BGP). i have already secured ASN & dedicated IP address for this purpose.

I would like to do the following setup,

1) There is two transit 100 Mb links from the same ISP which i need to do Multi homing as Active/standby on the router .

 
2) Link connected to RTR-1 must be always the main traffic path both for Inbound/outbound. during link failure all the inbound/outbound shud flow through RTR-2 using 2nd link.

3) All the 1000 nos IPs should be advertised to all two circuits.

We have been assigned with 1000 nos IP from along with ASN number.

Could you help me on this design part & suitable BGP configuration

Any help will be highly Appreciated 

Thanks

[Jose Jara]

Hi,

configure iBGP between RTR-1 and RTR-2 and then manipulate BGP attributes in order to make RTR-1 the main traffic path:

- Outbound traffic: apply a route-map in the inbound direction towards ISP PE, setting local preference 200.

- Inbound traffic: apply a route-map in the outbound direction towards ISP PE, setting MED to 200.

Hope this helps,

Jose.

[Shibu1978]

Hi,

Thanks for the reply.

Our case we have configured BGP only to these routers and rest all devices under these are operating static routes only & RTR1 & 2 are not sharing the BGP routes between them.

Just to clarify is it required to run iBGP between RTR-1 & 2?  as  Perimeter vlan default route is pointing to the HSRP ip from the firewall & RTR-1 is configured with high priority. tracking the first link other end will achieve the failover right?

.

Could you share any sample configs?

Thanks

[Jose Jara]

Hi,

It is better to configure internal BGP between the devices and, if it´s possible, a back-to-back cable between RTR-1 & 2. Otherwise, you rely on HSRP tracking which may o may not work properly. Also, the design is more robust as it will handle double failures like WAN main link- LAN backup link. 

Regarding the configs, I am sure you can find examples in Cisco website.

Best Regards,

Jose.

[Shibu1978]

Hi,

Thanks,

I have seen many but if it is really appreciable if your could give me a working (already tested and working ) configurations :)

Thanks for your time 

[Shibu1978]

Dear all,

Could some one help me with the config sample pl :)

Thanks in advance

[Jose Jara · Accepted solution]

Route-map to give preference to outbound traffic, applied to Main Router:

route-map MAIN 

set local-preference 200

then, apply it to the ISP neighbor:

neighbor x.x.x.x route-map MAIN in

Route-map to give less preference to inbound traffic, applied to Backup Router:

route-map BACKUP

set metric 200

then, apply it to the ISP neighbor:

neighbor x.x.x.x route-map BACKUP out

iBGP configuration:

Backup Router:

neighbor MAIN remote-as ASN_CPEs

neighbor MAIN next-hop-self

Main Router:

neighbor BACKUP remote-as ASN_CPEs

neighbor BACKUP next-hop-self

[Shibu1978]

Thanks.

Meanwhile we will not be configuring ibgp between routers will go with IP sla tracking . will it work with the config above? if not could you give the suitable config.. Thanks 

[Shibu1978]

Hi Jose jara,

Meanwhile we will not be configuring ibgp between routers will go with IP sla tracking . will it work with the config above? if not could you give the suitable config.. Thanks