There’s a lot of talk in the industry about network virtualization. VXLAN is one of the encapsulation protocols you can use, and it’s the focus of today’s show.
We’ll discuss why you might want to virtualize your network, and why you’d use an overlay.
If you do go down this road, what are the design considerations you need to keep in mind as you put this system together? We’ll talk about VXLAN use cases, pros and cons, and debate the finer technical points of L2/L3 data center networking.
Three guests join us to delve into VXLAN:
Lukas Krattiger, Technical Marketing Engineer, Cisco Systems
Use Cases – Why does an organization add overlays to their network?
- vMotion between DCs / L2 (contained in the overlay) vs L3 (unique address space between DCs)
- Similar to above, preserving L2 adjacency between services
- Allow mobility for apps
- VXLAN is not for compute virtualization only
- VXLAN is not DCI, but it helps
Components – What are the major elements for this solution?
- It’s just another overlay/encap type
- Understanding the VNID
- Rare that 802.1q 4096 isn’t enough in enterprises
- Multicast “control plane” by default (i.e. no control plane) for VTEPs to learn location of endpoints (aka Flood&Learn)
-Routing protocols are built for transporting routed protocols, now we put Layer 2 overlays on top (new requirements)
-As Layer 2 has (mostly) multi-destination traffic, unicast alone might not be good enough
-Some key requirements for Layer 3 underlay (Unicast, Multicast)
- Interface types
- IPv4, IPv6
- PIM ASM vs. BiDir and RP redundancy/load balancing
-Some key differentiators in regards to the Protocols (OSPF vs, IS-IS vs. EIGRP vs BGP)
-Differences between a Layer-3 Underlay vs. a Layer-3 Fabric (MSDCs)
-What if we put VXLAN on top?
- Unicast and Multicast specifics for VXLAN
- VTEP reachability
- BUM traffic
- Multicast vs. MP-BGP control plane for VXLAN
NSX for vSphere: VXLAN Control Plane modes explained – Dmitri Kalintsev
TCP/IP Over VXLAN Bandwidth Overheads – Steven Iveson