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VXLAN Journey - Part 01 - What is VXLAN and how it works (Cisco Nexus Switch) - Basic data plane learning

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For several years I have worked with Data-Center network based on VXLAN. Anyone suddenly start working with production DC-networks built on top VXLAN - with Spine-Leaf topology and Multi-Site - they will get lost easily. Also lack of good step by step written books from the vendors Cisco, Arista, Juniper etc. make it difficult to understand the technologies/protocols used for VXLAN in DC-network.  Let's try to solve the problem - by building a DC-network from scratch and step by step using Cisco Nexus switches. What is VXLAN? The most common answer is - tunnelling a layer-2 packets over layer-3 network. I define it another way - the whole DC is a fabric. A fabric consists of several switches. With VXLAN, the whole DC-Fabric becomes a single switch (of course - logically). We are eliminating three fundamental problems in DC -  The network core becomes Spanning Tree Protocol (STP) free. All the physical links in the core are used Equal-cost multi-path routing (ECMP). The network...
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Cisco IOS-XE Vrf Route Leaking In Single Router using VASI interfaces

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For a long time I missed one feature in Cisco IOS-XE routers while working with multiple Vrfs. If somehow I could have a logical/virtual point-to-point links connecting two Vrfs. The feature I am talking about exactly same as Fortigate firewalls offer - vdom-links; which connects two vdoms using a virtual p-to-p links. It looks like Cisco has already implemented such feature which is called - VASI (VRF-Aware Software Infrastructure ). With VASI-interfaces we can connect two vrfs (including global vrf); using a logical p-to-p link. One side of a VASI-link will called - vasileft (belongs to a vrf) and another side will be called vasiright (belongs to another vrf). If we assign an IP address to those left/right interfaces; we have connected the two Vrfs. After that we can easily implement route leaking between the vrfs using static routing, dynamic routing protocols (ospf, bgp) etc. Enough theory; lets start configuring our topology which looks like below - 01 - Network Topology Our topol...
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Location: Täby, Sweden
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