Design Multisite Network : WAN

[choylee]

Hi,

We can see the main site A with the multi-homing BGP configuration (mode default route with ISP) as attached.

Currently, I don't have IGP on the site A (static route only)

I would like to add the site B in order to have a DR.

I have the private link between the site A and B (Gbic fiber) and I could configure a tunnel GRE over Internet between both sites.

If I decide to add the third router r03 in my AS and I choose the different IP prefix (NRLI) on the site B.

Then, which the best way to add this site ?

Should I add r03 with iBGP ?

Best !

[Jason M.]

Is the site B connection BGP as well?

What are the bandwidth of the ISP connections?

If you have you own block advertised through site A I would just add site B with statics or an IGP. If you have a 1G connection between the sites it's better to use that instead of having site B attract traffic directly anyway. Especially if site A has more internet bandwidth available. The description is not detailed enough to give an accurate assessment though.
 

[choylee]

Hi,

Yes the site B could be connected with ISP C using BGP session. 

I'm used to 90 Mbits/s of Internet bandwith (both ISP A and B)
I don't have limit about bandwith.

As follow the illustration, the bandwidth is :
ISP A  : 50 Mbits/s
ISP B : 40 Mbits/s
ISP C : 1 Gbits/s
LAN_to_LAN (intersite) : 1 Gbits/s 

Thanks

[Jason M.]

Makes sense to use iBGP between the sites and with the site B ISP. May have to adjust your advertisements based on the resulting traffic load but you should have all of your IP blocks advertised to all ISPs.