VxLAN | Part 4 - Address Learning

You know that VTEPs encapsulate traffic in VNI’s, to send over an overlay network tunnel. But how does the sending VTEP find the destination VTEP? How are MAC to IP bindings learned?

Let’s start with how Broadcast, Unknown Unicast, and Multicast (BUM) traffic are handled. The two methods are multicast groups and head end (or ingress) replication.

VNI’s can be mapped to multicast groups. When BUM traffic is sent, it will be sent to the group, rather than everywhere. When VTEPs start, they use IGMP to join the correct groups.

With head end replication, the frame is duplicated and sent to each relevant VTEP. This does not scale as well as multicast.

There are two ways to learn about MAC addresses as well. The first is flood-and-learn (AKA data plane learning), which acts like ethernet.

The other is control plane learning, which uses BGP #EVPN to learn MAC addresses before they are needed. This is like learning routes.

#VxLAN address learning Explained! In this video we’ll look at bridging vs routing, head end replication, multicast, and take a deep dive into how control plane and data plane learning work.


I also suggest reading ‘Building Data Centers with VXLAN BGP EVPN’ by Lukas Krattiger
https://click.linksynergy.com/link?id=RL4E*8CmbSY&offerid=145238.2463561&type=2&murl=http%3A%2F%2Fwww.ciscopress.com%2Ftitle%2F9781587144677


Part 1: Fundamentals - An introduction or primer into the basic concepts and terminology. For example, VxLAN vs VLAN, and host vs gateway. https://youtu.be/YNqKDI_bnPM

Part 2: Header Format - Follow the packet flow to see the headers added to a frame. https://youtu.be/jjr8aIIRkYc

Part 3: Spine Leaf Topology - Looks at the hierarchical architecture, and compares it to the newer spine leaf topology. https://youtu.be/x1F-RCW9fqo

Part 4: Address Learning - BUM traffic, data plane or control plane learning, multicast, and ingress replication.

Part 5: Bridging Configuration - A technical deep dive into flood-and-learn (bridging) and multicast configuration on Cisco Nexus 9000 switches.
https://youtu.be/PbklbQCmsbc

Part 6: BGP EVPN Configuration - A technical deep dive into control plane learning (BGP EVPN) and Ingress replication configuration on Cisco Nexus 9000 switches.
https://youtu.be/D9k9_hRdrGc


This video is also helpful in CCNA #DataCenter, CCNP Data Center, and CCIE Data Center.
200-155, DCICT
300-180, DCIT
300-160, DCID
300-165, DCII

https://www.youtube.com/c/networkdirection

https://twitter.com/NetwrkDirection

https://www.patreon.com/NetworkDirection


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