Category: Overlay Networks

After the Designing Private Cloud Infrastructure workshop I had in Slovenia last week (in a packed room of ~60 people), someone approached me with a simple question: “I like the idea of using overlay virtual networks in my private cloud, but where do I start?”

I wrote (and spoke) at length about layer-2 and layer-3 gateways between VLANs and overlay virtual networks, but I still get questions along the lines of “how will you connect legacy servers to the new cloud infrastructure that uses VXLAN?”

There are tons of SDN workshops, academies, and webinars out there, many of them praising the almost-magic properties of the new technologies, or the shininess of vendors’ new gadgets and strategic alliances. Not surprisingly, the dirty details of real-life deployments aren’t their main focus.

As you might expect, my 2-day workshop isn’t one of them.

Brook Reams sent me an interesting tidbit: Brocade is the first vendor that actually shipped a VXLAN VTEP controlled by a VMware NSX controller. It’s amazing to see how Brocade leapfrogged everyone else (they also added tons of other new functionality in NOS releases 4.0 and 4.1).

Not sure I published a link to this video: the overview of VMware NSX Architecture (for additional details watch other videos from the VMware NSX Architecture webinar).

If you plan to attend the Troopers 2014 conference in two weeks, don’t forget to include my full-day SDN workshop on Tuesday in your agenda (the Troopers conference is sold out, but you can still register for the workshop). The topics of the workshop will include:

• Why do we need SDN and what is it?
• OpenFlow, its advantages, drawbacks and scalability challenges;
• Typical OpenFlow and SDN deployment considerations;
• Real-life SDN use cases, both OpenFlow- and non-OpenFlow ones;
• Network function virtualization;
• Software-defined data centers.

For more details, check out the workshop description; for other SDN-related materials visit my SDN Resources page.

The layer-3-only Hyper-V Network Virtualization forwarding model implemented in Windows Server 2012 R2 thoroughly confuses engineers used to deal with traditional layer-2 subnets connected via layer-3 switches.

As always, it helps to take a few steps back, focus on the principles, and the “unexpected” behavior becomes crystal clear.

2014-02-05: HNV routing details updated based on feedback from Praveen Balasubramanian. Thank you!

If you want to implement overlay virtual networking with VMware products today, you have two options: use vCNS 5.5 or NSX for vSphere… and I would be hard pressed to choose one or the other.

During my ExpertExpress engagements with engineers building multi-tenant cloud infrastructure I often get questions along the lines of “How do I integrate my public IaaS cloud with my MPLS/VPN WAN?” Here are a few ideas.

Gordon sent me a whole list of NSX gateway questions:

• Do you need a virtual gateway for each VXLAN segment or can a gateway be the entry/exit point across multiple VXLAN segments?
• Can you setup multiple gateways and specify which VXLAN segments use each gateway?
• Can you cluster gateways together (Active/Active) or do you setup them up as Active/Standby?

The answers obviously depend on whether you’re deploying NSX for multiple hypervisors or NSX for vSphere. Let’s start with the former.