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VXLAN Journey - Part 03 - Explanation of Vrf/Multitenancy (L3VNI), RD and RT auto generation (32/64 bit ASN), Anycast Gateway

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We have covered basic VXLAN implementation using BGP-EVPN control plane in Part 02 . We will continue that journey in this blog by having a detail look at - Vrf/Multitenancy ( L3VNI ), RD and RT auto generation ( 32/64 bit ASN ) and Anycast Gateway . We will still continue with just two switches connected back-to-back for simplicity. We need to understand the technology first before scaling up the topology. L3VNI We already know about L2VNI - which are our vlans. Let's assume our switches are gateway/router for two different vlans -  VLAN (101) - L2VNI (100101) - Subnet (10.85.101.0/24) VLAN (102) - L2VNI (100102) - Subnet (10.85.102.0/24) How we are going to route traffic between those subnets? Also vlans can belong to different customers - how we are going to isolate traffic between vlans of different customers? The magic answer is our classic concept of VRFs in a router. With different VRFs we will isolate traffic between different customers. In VXLAN each VRF is allocated a VN...
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VXLAN Journey - Part 02 - What is VXLAN and how it works (Cisco Nexus Switch) - Basic control plane learning

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We have covered some basic theories/concepts regarding VXLAN and implemented a simple topology using data-plane learning in Part 01 . Now we will use the same topology to implement VXLAN using control-plane learning. Why I am calling the topology - control-plane  learning? This time we will use routing protocols - OSPF, BGP etc. to build our VXLAN tunnels dynamically and exchange forwarding information. Let's talk about our routing protocols first. We will use OSPF for underlay unicast routing. For overlay we will use BGP-EVPN address family to exchange forwarding information. BGP EVPN Type-2 routes ( MAC/IP Advertisement Route ) will be used to forward traffic between our clients. BUM traffic will be forwarded using BGP EVPN Type-3 routes . For simplicity we will not use multicast protocol (PIM etc.) for BUM traffic. Instead we will rely on BGP Head-End-Replication (also known as ingress replication ) for BUM traffic forwarding. A little refresher about - RD and RT in BGP...
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