On Mon, Feb 25, 2013 at 3:23 AM, Glen Kent <glen.kent@gmail.com> wrote:
Yahoo, Google, etc applications are running on one server and each application could be theoretically associated with a unique VXLAN tag. This way service providers will be able to provide QoS per application (by effectively providing QoS to the VXLAN carried in the pkts). So now Youtube for example, can get unique QoS treatment from our desktops to the edge of the network. Form there on core routing will pick up - which remains largely unaffected by VXLANs.
OpenFlow is useful because it provides a common "CLI/SNMP" with which all routers from all vendors can be provisioned and monitored. As an example, VPLS configuration in Juniper, CIsco and AlaLu routers will be very different. So, provisioning a VPLS service in a network that comprises of these 3 vendors would require the admins to know the CLIs of all these routers. If these routers support OpenFlow, then theoretically, one configuration would work on all routers. OpenFlow would like say "Provision a LSP" and each router will internally provision an LSP. The admin remains oblivious to the internal CLIs of these boxes.
The SDN controller is a SW that can again theoretically be made aware of the entire network. It can look at SNMP traps, etc and can figure out the exact topology of the network. Based on the SNMP traps, messages it can determine all failures in the network. It can run routing protocol simulations and figure out the best topology in the network. This can, using OpenFlow, be programmed on all routers. So, all heavy CPU processing task is taken over by the SDN controller. The controller can also take in requests on what network aware applications require and feed that to the routers/switches in the network and thus you have an application aware network provisioned.
Glen
Hi Glen; You've got a bit of "buzzword bingo" going on in those three paragraphs... Perhaps I can steer you in the right direction by categorizing and pointing you to some search topics.: VxLAN -- This is in the category of Overlay Networks. Check out the draft RFC, and search for terms like "VxLAN tutorial" or "VxLAN primer". Think "encapsulation" and "segmentation beyond 4k vlan tags." Don't confuse OpenFlow with VxLAN, although there's more than one use-case where either could theoretically be used. Note that VxLAN is just one of a few OLN protocols out there, and none of them have reached very far beyond the hype curve yet. OpenFlow vs. OpenStack -- The actual OpenStack project documentation is a great place to start here. Orchestration is another category with several competing efforts, so read as much as possible! SDN -- Consider this the broad category, but avoid overly broad terms like "SDN Controller" in favor of "<specific> controller" until you have the big picture filled in. For example, "OpenFlow Controller": There are plenty of docs to read on that specific subject, and there was a stellar tutorial for first-timers at the start of NANOG57. ...and lastly, the "killer apps": Don't bother researching this until you've covered the basics above. There are plenty of vendors and researchers out there doing the legwork on "killer SDN apps", but you'll want to understand all the underlying technologies first. -Jeff