Ivan, See my comments inserted below:
> -----Original Message----- > From: Ivan Pepelnjak [mailto:[email protected]] > Sent: Saturday, August 25, 2012 10:23 AM > To: Linda Dunbar > Cc: Black, David; [email protected] > Subject: Let's refocus on real world (was: [nvo3] Comments on Live > Migration and VLAN-IDs) > > On 8/24/12 11:11 PM, Linda Dunbar wrote: > [...] > > > But most, if not all, data centers today don't have the Hypervisors > > which can encapsulate the NVo3 defined header. The deployment to all > > 100% NVo3 header based servers won't happen overnight. One thing for > > sure that you will see data centers with mixed types of servers for > > very long time. > > > > If NVEs are in the ToR, you will see mixed scenario of blade servers, > > servers with simple virtual switches, or even IEEE802.1Qbg's VEPA. So > > it is necessary for NVo3 to deal with the "L2 Site" defined in this > > draft. > > There are two hypothetical ways of implementing NVO3: existing layer-2 > technologies (with well-known scaling properties that prompted the > creation of NVO3 working group) or something-over-IP encapsulation. > > I might be myopic, but from what I see most data centers today (at > least > based on market shares of individual vendors) don't have ToR switches > that would be able to encapsulate MAC frames or IP datagrams in UDP, > GRE > or MPLS envelopes. I am not familiar enough with the commonly used > merchant silicon hardware to understand whether that's a software or > hardware limitation. In any case, I wouldn't expect switch vendors to > roll out NVO3-like something-over-IP solutions any time soon. > [Linda] I have to say this is incorrect. ToR switches are capable of doing VxLAN and GRE encapsulations. > On the hypervisor front, VXLAN is shipping for months, NVGRE is > included > in the next version of Hyper-V and MAC-over-GRE is available (with Open > vSwitch) for both KVM and Xen. Open vSwitch is also part of standard > Linux kernel distribution and thus available to any other Linux-based > hypervisor product. > > So: all major hypervisors have MAC-over-IP solutions, each one using a > proprietary encapsulation because there's no standard way of doing it, > and yet we're spending time discussing and documenting the history of > evolution of virtual networking. Maybe we should be a bit more > forward-looking, acknowledge the world has changed, and come up with a > relevant hypervisor-based solution. > > Furthermore, performing something-in-IP encapsulation in the > hypervisors > greatly simplifies the data center network, removes the need for > bridging (each ToR switch can be a L3 switch) and all associated > bridging kludges (including large-scale bridging solutions). Maybe we > should remember that "Perfection is achieved, not when there is nothing > more to add, but when there is nothing left to take away" along with a > few lessons from RFC 3439. > > I am positive a decade from now we'll see ancient servers still using > VLAN-only hypervisor switches (or untagged interfaces), so there might > definitely be an need for an NVO3-to-VLAN gateway, but we shouldn't > continuously focus our efforts on something that's probably going to be > a rare corner case a few years from now. [Linda] For applications which requires more than one "computing engine" to accomplish a task might need dedicated servers instead of VMs. > > ... or I may be completely wrong. Wouldn't be the first time. > Ivan _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
