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 +, 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.
