On Wed, Jan 21, 2015 at 12:22 PM, Ronald van der Pol < ronald.vander...@rvdp.org> wrote:
> On Mon, Jan 19, 2015 at 22:55:04 +0000, Dave Bell wrote: > > > "http://www.rvdp.org/presentations/SC11-SRS-8021ag.pdf" > > The 802.1ag code used is open source and available on: > https://svn.surfnet.nl/trac/dot1ag-utils/ > > > Of course if you want fast failover, you need to send packets very > > rapidly. Every 250ms is not unreasonable. This is going to cause the > > control plane to get very chatty. Typically on high end routers, > > processes such as BFD are actually ran on line cards as opposed to on > > the routing engine. When a failure is detected this reports up into > > the control plane to trigger a reconvergence event. I see no reason > > why this couldn't occur using SDN. > > Exactly. This is something you want to do in hardware, especially > if you want to do fast reroute with the OpenFlow group table. > Problem is that many 1U OpenFlow switches do not support 802.1ag. > We made the propotype mentioned above to show and investigate the > benefits of OAM. The closed "open" networking foundation is supposed > to be working on this, but I don't know the status because their > mailing lists are closed. > > In SDN/OpenFlow I think a couple of things are needed: > - configure 802.1ag on the interfaces (via ofconfig?) > - configure OpenFlow paths (e.g. primary and backup) and also create > forwarding entries for 802.1ag datagrams along those paths > - configure fast reroute with the group table (ofconfig?) > Fast reroute (in the form of fast failover) is supported in the OF spec (1.3+), using Group Tables. > By doing this detection and failover are handled in hardware. > > rvdp > Data plane reachability could be performed in SDN/OpenFlow networks using BFD/ Ethernet CFM (802.1ag), Y.1731, preferably on silicon if there is support (which i believe every silicon vendor should work on). It would not be ideal if these OAM frames are forwarded to a central controller. Today - I think it is done on some form of software layer (ovs, sdks) that reside on these OF switches.