Geneve: Generic Network Virtualization Encapsulation

Earlier this year, VMware, Microsoft, Red Hat and Intel published an IETF draft on Generic Network Virtualization Encapsulation (Geneve). This draft (first published on Valentine’s Day no less) includes authors from the each of the first generation encapsulation protocols — VXLAN, NVGRE, and STT. However, beyond the obvious appeal of unification across hypervisor platforms, the salient feature of Geneve is that it was designed from the ground up to be flexible. Nobody wants an endless cycle of new encapsulation formats as network virtualization designs and controllers mature, certainly not the vendors that have to support the ever growing list of acronyms and RFCs.

Of course press releases, standards bodies and predictions about the future mean little without actual implementations, which is why it is important to consider the “ecosystem” from the beginning of the process. This includes software and silicon implementations in both commercial and open source varieties. This always takes time but since Geneve was designed to accommodate a wide variety of use cases it has seen a relatively quick uptake. Unsurprisingly, the first implementations that landed were open source software — including switches such as Open vSwitch and networking troubleshooting tools like Wireshark. Today the first hardware implementation has arrived, in the form of the 40 Gbps Intel XL710 NIC, previously known as Fortville.

Why is hardware support important? Performance. Everyone likes flexibility, of course, but most of the time that comes with a cost. In the case of a NIC, hardware acceleration enables us to have our cake and eat it too by offloading expensive operations while retaining software control in the CPU. These NICs add encapsulation awareness for classic operations like checksum and TCP segmentation offload to bring Geneve tunnels to performance parity with traditional traffic. For good measure, they also add in support for a few additional Geneve-specific features as well.

Of course, this is just the beginning — it is still only six months after publication of the Geneve specification and much more is still to come. Expect to see further announcements coming soon for both NIC and switch silicon and of course new software to take advantage of the advanced capabilities. Until then, a discussion session as well as a live demo will be at Intel Developer Forum this week to provide a first glimpse of Geneve in action.

转自http://networkheresy.com/2014/09/08/geneve-ecosystem-support-has-arrived/