Category: Workshop

Last week I explained how layer-2 and layer-3 packet forwarding works in VMware NSX – a solution that closely emulates traditional L2 and L3 networks. Hyper-V Network Virtualization (HNV) is different – it’s almost a layer-3-only solution with only a few ties to layer-2.

In the first Terastream blog post I mentioned Deutsche Telekom decided to use an IPv6-only access network. Does that mean they decided to go down the T-Mobile route and deployed NAT64 + 464XLAT? That combo wouldn’t work well for them, and they couldn’t use MAP-E due to lack of IP address space, so they deployed yet another translation mechanism – Lightweight 4over6.

The easiest way of connecting overlay virtual networks implemented with VMware NSX for vSphere to the outside world is NSX Edge Services Router. It’s a much improved version of vShield Edge and provides way more than just layer-3 forwarding services – it’s also a firewall, load balancer, DHCP server, DNS forwarder, NAT and VPN termination device.

Dan sent me the following question:

I had another read of the ‘Building IPv6 Service Provider Networks’ material and can see the PE routers use site local ipv6 addressing. I’m about to build another small service provider setup and wondered: would you actually use site local for PE loopbacks etc, or would you use ULA or global addressing? I’m thinking ULA would be better from a security point of view?

TR&DR summary: Don’t do that.

Even though I questioned the wisdom of writing your own network programming applications, I know I would immediately jump into those waters if I were 20 years younger. If you’re like my younger self, you might want to keep a few guidelines in mind.

All overlay virtual networking solutions look similar from far away: many provide layer-2 segments, most of them have some sort of distributed layer-3 forwarding, gateways to physical world are ubiquitous, and you might find security features in some products.

The implementation details (usually hidden behind the scenes) vary widely, and I’ll try to document at least some of them in a series of blog posts, starting with VMware NSX.

Traditional data centers are usually built in a very non-scalable fashion: everything goes through a central pair of firewalls (and/or load balancers) with thousands of rules that no one really understands; servers in different security zones are hanging off VLANs connected to the central firewalls.

Some people love to migrate the whole concept intact to a newly built private cloud (which immediately becomes server virtualization on steroids) because it’s easier to retain existing security architecture and firewall rulesets.

The recent Juniper product launch included numerous components, among them: a new series of data center switches (including a badly-needed spine switch), MetaFabric reference architecture (too meta for me at the moment – waiting to see the technical documentation beyond the whitepaper level), and (finally) a leaf-and-spine virtual chassis – Virtual Chassis Fabric.

Every good data center presentation starts with redefining The Problem and my VMware NSX Architecture webinar was no exception – the first section describes Infrastructure-as-a-Service Networking Requirements.

I sprinted through this section during the live session, the video with longer (and more detailed) explanation comes from the Overlay Virtual Networking webinar.

During the final part of the IPv6-only data centers webinar Tore Anderson described his deployment guidelines and answered a few more questions.