Hi Experts,
We are planning to have a CLOS Fabirc (VXLAN EVPN) up and I am finding it difficult when trying to optimize routing. I have attached a diagram for better understanding. We have multiple VRFs (tenants) We are peering with and upstream service provider for Internet. They are sending us the default route. External connections for Internet is physically terminated in the Border Leaf. As per the agreement with ISP we cannot use the standby links unless there is a failure on the primary link, therefor we are trying to enhance the routing. Each Border Leaf is peering with ISP router 01 and router 02. Both ISP routers are sending a default route. Our requirement is as below; 1. If traffic reaches to Border Leaf 01 - It should exit to ISP router 01 preferably. This we can control using local preference and to avoid asymmetric routing we can use AS path prepend. 2. If the traffic reaches Border Leaf 02 - It should exit to Border Leaf 01 and then from Border Leaf 01 to ISP router 01. We understand that we can use a VLAN with /30 subnet and use that to build a iBGP between the Border Leaf switches. This new VLAN will be allowed over the VPC peer link.
We would like to know that
- Allowing the VLAN's used for iBGP over the VPC peer links are recommended design? Or do we need to have a dedicated Layer 3 link between Border Leaf switches?
- Is there any other way to achieve this requirement using VXLAN EVPN manipulation?
- Does the system nve infra vlan scenario help us here to achieve the same requirement without using iBGP? https://www.cisco.com/c/en/us/support/docs/switches/nexus-9000-series-switches/214624-configure-system-nve-infra-vlans-in-vxla.html
