Redundancy AND loadsharing with two HQ sites

[l.marrone]

Hi all,

I have two HQ sites (HQ1 and HQ2), with CE's advertising SAME network (i.e. 2.2.2.0/24) to their PE (single VPN).

If I would some "spoke" site use HQ1 to reach 2.2.2.0/24 and HQ2 for redundancy, AND another "spoke" site use HQ2 to reach 2.2.2.0/24 and HQ1 for redundancy:

Is it better use 2 VPN ?

How if I use only single VPN ?

Thanks in advance.

[l.marrone]

If I use iBGP multipath on all destination PE's, I'm able to load balance (per destination via CEF) to reach 2.2.2.0/24 but I want redundancy (HQ1 first and HQ2 second) for one half of sites and vice versa for second half of sites.

2 VPN's ?

[suguilian]

you can use one VPN to achieve this. Since ISP's PEs connecting to you run the same routing protocol with you, so you can ask your ISP to modify the metric for your HQ network (2.2.2.0/24)on the PEs which connects to your spokes.

[mheusinger]

The comment is right, one VPN would be sufficient.

There is one requirement though, which has to be met otherwise you do not achieve your goal. A BGP router will only send an update about the best path it has for a certain prefix. In most cases route-reflectors will be implemented in a MPLS VPN environment to distribute bgp updates between PEs. So to allow to choose between HQ1 and HQ2 in your case, the respective VRF have to use different RD values. Otherwise the RR will only send one BGP path (either to HQ1 or to HQ2) and all traffic will end up there.

So: different RD for HQ1 and HQ2, ONE route-target for your VPN and modified metric on "spoke" CE would be the solution - possibly through an import map and the use of communities.

regards

Martin

[l.marrone]

Thank you all for aswers.

With different RD for HQ1 and HQ2, I get on spoke PE's both routes.

But, if on the same spoke PE I would have type-1 sites (HQ1 first and HQ2 bck) and type-2 sites (HQ2 first and HQ1 bck), how can I do ? Policy routing ?

This is my problem.

Thanks in advance

[svibert]

Hi

I have implemented this solution for a customer.

I use eBGP4 redistribution between the SP's PE and my CE.

I would cut the /24 into two /25 subnets, subnet1 and subnet2.

I would configure the BGP MED with a higher cost for subnet1 and a lower cost for subnet2 on HQ1 and vice versa on HQ2.

Therefore I have some sort of load balancing where people wanting to access the subnet will go via a site or another depending if they want to access 2.2.2.0 to 2.2.2.127 or 2.2.2.129 to 2.2.2.254.

Hope this helps.