Technology Brief : VXLAN - Introducing Overlay Networking скачать в хорошем качестве

Technology Brief : VXLAN - Introducing Overlay Networking

The third video in the VXLAN series. More information at www.network-insight.net Overlay/Underlay Essentially, an overlay is either placing Layer 2 or Layer 3 over a Layer 3 Core. The Layer 3 Core is known as the underlay. This removes a lot of the drawbacks and scaling issues which we had with traditional Layer 2 connectivity which uses VLANs. The multi-tenant nature of overlays is designed to get away from these L2 challenges allowing you to build networks at a much larger scale. Layer 2 and layer 3 overlays We have both Layer 2 and Layer 3 overlays. Layer 2 overlays emulate a Layer 2 network and map Layer 2 frames into an IP underlay. If you are emulating a Layer 2 network, you have to somehow emulate Layer 2 flooding behavior. This is the bread and butter how Layer 2 networks work, and that doesn't change just because you decide to create a Layer 2 overlay. While Layer 2 overlays encapsulate Layer 2 frames into IP. Layer 3 overlay maps IP into IP. VXLAN is the most popular overlay types transporting Layer 2 or Layer 3 over Layer 3 IP underlay core. The end hosts are completely oblivious to any Layer 2 or Layer 3 tunneling mechanisms that is taking place and will always simply send an Ethernet Frame. As far as they are concerned nothing has changed and their connectivity models remain. Architecture - simple core and intelligent edge The underlay can consist of any architectural design be it Flat, Hub-Spoke or Ring for example but by far the most popular fabric is a 3. Leaf & Spine architecture. The architecture of the overlay/underlay model pushes the complexity to the edges of the network where the overlay tunnels are created. The core is left alone to forward packets as quickly as possible. There is usually very little complexity in the core and you might only have some basic QoS and VLAN configurations. The idea is to always keep the core configuration as simple as possible. This has proved to be a very efficient way to scale data centers; simple Core and Intelligent edge. Similarly to how the Internet is built. Music from Bensound.