MPLS addition router between 2 sites

[louis0001]

Hi,

we have 2 sites that we would like to link together for redundancy using BGP

The two sites are also connected (R1 & R2) to an ISP provide private MPLS network to our other 50 remote sites.

We would like to add a bit of redundancy between SITE A & SITE B (R3 & R4) so we're not 100% reliant on the ISP provided network.

Do we just add the routers into the same site AS eg R1 & R3 = AS 61000 and R2 & R4 = AS 61001 or create another private AS for each router and add them like that? Do we need to specify each as a neigbor and do we need to use route reflectors etc?

We would like all the remote sites to be aware of the new routers so that if the ISP link to SITE A failed, remote sites could reach SITE A via SITE B

Any pointers or BGP config example would be appreciated.

Thank you

[rais]

All you need is an eBGP connection between the two new routers/link R3 and R4.

R1 and R2 need to advertise other site's prefixes to ISP as well.

HTH.

[louis0001]

Hi,

thanks for reply. So, would it go something like below?

R1 (SITE A)

router bgp 61000

network 10.1.1.0 mask 255.255.255.0   <<< SITE A Lan

neigbour 10.190.0.2 remote-as 11111   <<< ISP

R2 (SITE B)

router bgp 61001

network 10.2.1.0 mask 255.255.255.0   <<< SITE B Lan

neigbour 10.190.0.6 remote-as 11111   <<< ISP

R3 (SITE A)

router bgp 61000

network 10.1.1.0 mask 255.255.255.0   <<< SITE A Lan

neigbour 192.168.1.2 remote-as 61001   <<< SITE B (R4)

R4 (SITE B)

router bgp 61001

network 10.2.1.0 mask 255.255.255.0   <<< SITE B Lan

neigbour 192.168.1.1 remote-as 61000   <<< SITE A (R3)

[rais]

Correct.

Also, you need iBGP between R1-R3 and R2-R4.

Regards.

[louis0001]

Hi,

I've not setup iBGP before. Would it be as simple as adding the other router in the same AS as a neigbor?

eg

R1 (SITE A)

router bgp 61000

network 10.1.1.0 mask 255.255.255.0   <<< SITE A Lan

neigbour 10.190.0.2 remote-as 11111   <<< ISP

neigbour 10.1.1.1 remote-as 61000   <<< R3

R3 (SITE A)

router bgp 61000

network 10.1.1.0 mask 255.255.255.0   <<< SITE A Lan

neigbour 192.168.1.2 remote-as 61001   <<< SITE B (R4)

neigbour 10.1.1.2 remote-as 61000   <<< R1

Is there anything to look out for here? eg route reflectors etc?

[rais · Accepted solution]

That's correct. No need for route reflectors.