SHARIFUL's TECH BLOG

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...

In our previous blog post -  Stacking switches Part - V (Cisco Nexus vPC - Virtual Port Channel) , we have looked at how to configure vPC between two nexus switches. But we were at a huge disadvantage - because of the underlying architecture how vPC/MLAG works. With any MLAG implementation, we are still managing two individual switches, they are just facilitating a LACP aggregation link which is spread throughout the vPC peers. And we are configuring the same things twice - one time in each peer of our vPC domain. There is always risk in such setup that we miss some configuration commands in one of the switch and the vPC interfaces does not comes up. Cisco has implemented a feature called switch-profile which allows configuration syncing to all the vPC peer switches. We just configure a profile in both peer switches, make our configuration changes, then NX-OS validates the configuration and pushes it throughout the vPC domain. The good thing with config-sync is that it ...