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VXLAN Journey - Part 05 - ARP Suppression - optimizing ARP traffic in VXLAN

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What is ARP suppression? ARP suppression is a feature in VXLAN that reduces broadcast traffic by snooping Address Resolution Protocol (ARP) requests and replying from a local cache instead of flooding/broadcasting to the entire network. Let's have a look at out topology again -  01 - Network Topology Currently we have a stretched vlan 101 between our switches. The underlay is using HER/ingress replication for BUM traffic replication. When Vlan-101-Pc-01 tries to communicate with Vlan-101-Pc-02, it will generate ARP request. Leaf-Switch-01 will encapsulate the traffic in a VXLAN packet and forward the packet to all the VXLAN/NVE peers from which it has received a rt-3 (IMET) route for vni 100101. Let's assume we have stretched the vlan 101 to 10 different leaf switches. Then the ingress vtep (Leaf-Sw-01) will create 9 duplicate packets for the ARP request and forward it over the overlay. Now we will try to take a step back and optimize this ARP bum traffic duplication. Because o...
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VXLAN Journey - Part 04 - rt-2 (mac+ip), rt-5 (prefix-route), router-mac, symmetric irb and intra-vrf packet walkthrough

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In Part 03 - we have covered a lot of things related to single-site VXLAN implementation. But several things we have not explained. Let's explain them now. Network Topology Our topology is the same as previous blog - 01 - Network Topology Route-type 2 (mac+ip) We already know about rt-2 with which contains mac address of our connected hosts. Now we are seeing another type of rt-2 (mac+ip) which contains both mac and ip address of our connected hosts. This type of rt-2 will be generated if we have VRF/L3VNI only. Vlan 101 is configured on both Leaf-Sw-01 and Leaf-Sw-02.  But Vlan 102 is configured on Leaf-Sw-02 only.  Leaf-Sw-02 will send both combinations of rt-2 (mac) and rt-2 (mac+ip) to Leaf-Sw-01 for both the vlans. Leaf-Sw-02# show bgp l2vpn evpn neighbors 10.81.0.1 advertised-routes  Peer 10.81.0.1 routes for address family L2VPN EVPN: BGP table version is 426, Local Router ID is 10.81.0.2 Status: s-suppressed, x-deleted, S-stale, d-dampened, h-history, *-valid, ...
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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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