[ovs-discuss] Interval /transmission timer for particular MPs in CFM

Ben Pfaff blp at nicira.com
Mon Mar 19 16:49:13 UTC 2012


Oh.  Perhaps Ethan can help you.  I've forgotten how CFM worked in
1.2.

On Mon, Mar 19, 2012 at 01:16:56PM +0530, edward wilson wrote:
> Hi,
> 
> I am using OVS 1.2.2 which is requiring cfm_remote_mpid value.
> there is no cfm_remote_mpid(s) parameter in this.
> 
> now cfm working between 2 physical machine but when I am giving vlan tag 2
> on first machine physical interface and vlan tag 3 on second machine
> physical interface then also CCM packets are communicating without any
> issue.RDI is 0
> 
> -Ed
> 
> On Sun, Mar 18, 2012 at 10:19 PM, Ben Pfaff <blp at nicira.com> wrote:
> 
> > CFM works on the basis of an interface.  Configuring CFM on br0 is not
> > useful because the CFM packets transmitted on br0 do not go anywhere.
> >
> > There are various ways that you could avoid using two physical machines
> > to set up CFM, but CFM is more useful in the presence of two (or more)
> > physical machines.
> >
> > I do not see cfm_remote_mpid mentioned in ovs-vsctl(8).  Please let me
> > know where you saw this recommendation, so that we can correct the
> > documentation.
> >
> > OVS will place the remote MPs for which it receives CFM packets in
> > cfm_remote_mpids, for a manager to read.
> >
> > On Sun, Mar 18, 2012 at 09:03:02PM +0530, edward wilson wrote:
> > > Hi,
> > >
> > > After installing and configuring OVS, br0 will be there.
> > > 1. is that mean I have to use its physical interface with which br0
> > > attached like eth0.
> > > 2. is that mean I have to use 2 physical OVS machines at least for cfm
> > > set-up.
> > > 3. configuration of cfm_remote_mpid ,I got from ovs-vsctl config book. so
> > > my command would be now:-
> > > ovs-vsctl set Interface br0 cfm_mpid=1
> > > then how a machine will identify its remote MPs.
> > >
> > > -Ed
> > >
> > >
> > >
> > > On Sat, Mar 17, 2012 at 2:30 AM, Ben Pfaff <blp at nicira.com> wrote:
> > >
> > > > cfm_remote_mpids (note the "s") is not a column that you as a user
> > > > write.  It is a column that ovs-vswitchd writes.
> > > >
> > > > Ordinarily one would configure CFM on a physical interface or a
> > > > tunnel.  br0 is an internal interface.
> > > >
> > > > On Fri, Mar 16, 2012 at 09:19:44AM +0530, edward wilson wrote:
> > > > > OVS version 1.2.2
> > > > >
> > > > > following commands run on machine-
> > > > >
> > > > > first mahine-
> > > > > ovs-vsctl set Interface br0 cfm_mpid=1 cfm_remote_mpid=2
> > > > >
> > > > > second machine--
> > > > >  ovs-vsctl set Interface br0 cfm_mpid=2 cfm_remote_mpid=1
> > > >  >
> > > > > -Ed
> > > > >
> > > > >
> > > > >
> > > > > On Fri, Mar 16, 2012 at 8:53 AM, edward wilson
> > > > > <edward.wilson2601 at gmail.com>wrote:
> > > > >
> > > > > >
> > > > > >
> > > > > > First machine-
> > > > > >
> > > > > > ovs-appctl cfm/show br0
> > > > > >
> > > > > > MPID 1: fault recv_fault
> > > > > >
> > > > > >                  Interval: 1000ms
> > > > > >
> > > > > >                 Next CCM tx: 403ms
> > > > > >
> > > > > >                 Next fault check: 2744ms
> > > > > >
> > > > > >
> > > > > >
> > > > > > Remote MPID 2: fault
> > > > > >
> > > > > >                 Recv since check: false
> > > > > >
> > > > > >
> > > > > >
> > > > > > Second machime-
> > > > > >
> > > > > > ovs-appctl cfm/show br0
> > > > > >
> > > > > > MPID 2: fault recv_fault
> > > > > >
> > > > > >                  Interval: 1000ms
> > > > > >
> > > > > >                 Next CCM tx: 403ms
> > > > > >
> > > > > >                 Next fault check: 2744ms
> > > > > >
> > > > > >
> > > > > >
> > > > > > Remote MPID 1: fault
> > > > > >
> > > > > >                 Recv since check: false
> > > > > >
> > > > > > -Ed
> > > > > >
> > > > > >  On Thu, Mar 15, 2012 at 10:12 PM, Ben Pfaff <blp at nicira.com>
> > wrote:
> > > > > >
> > > > > >> Maybe you should show us your configuration.  It seems likely that
> > > > > >> there is just some misunderstanding.
> > > > > >>
> > > > > >> On Thu, Mar 15, 2012 at 05:30:19PM +0530, edward wilson wrote:
> > > > > >> > when I am creating cfm between two ovs ( one physical and other
> > VM
> > > > on
> > > > > >> same
> > > > > >> > machine) , CCM packet are with RDI bit set.
> > > > > >> > connection is not making between MPs.
> > > > > >> > both are on same bradcast domain.
> > > > > >> >
> > > > > >> > tried with two physical machines with OVS by giving same vlan
> > id,
> > > > but
> > > > > >> > result is same.
> > > > > >> >
> > > > > >> > -ed
> > > > > >> >
> > > > > >> > On Sat, Feb 18, 2012 at 2:27 AM, Ethan Jackson <
> > ethan at nicira.com>
> > > > > >> wrote:
> > > > > >> >
> > > > > >> > >   > Ed- same broadcast domain , you mean- I have to assign all
> > > > MPs in
> > > > > >> one
> > > > > >> > > vlan
> > > > > >> > > > or same network should be provided.
> > > > > >> > >
> > > > > >> > > The CFM module sends multicast CCMs on the interface upon
> > which
> > > > it's
> > > > > >> > > configured.  Presumably, multicast/broadcasts packets
> > egressing
> > > > this
> > > > > >> > > interface can reach some set of other hosts on the network.
> >  This
> > > > set
> > > > > >> > > can be restricted by using VLANs or other strategies.  How
> > this is
> > > > > >> > > done precisely, is out of the scope of the CFM module.  The
> > > > important
> > > > > >> > > thing is, when the CFM module broadcasts CCMs, all other MPs
> > that
> > > > > >> > > these CCMs reach need to have the same transmission interval.
> > > > > >> > >
> > > > > >> > > >> > 2) along with that I want to know how can I see the
> > current
> > > > timer
> > > > > >> > > value
> > > > > >> > > >> > by
> > > > > >> > > >> > any show command for particular MPids, I didn' tfind any
> > > > command
> > > > > >> for
> > > > > >> > > >> > this.
> > > > > >> > > >>
> > > > > >> > > >> ovs-appctl cfm/show will give you information about
> > currently
> > > > > >> configured
> > > > > >> > > >> CFM.
> > > > > >> > >
> > > > > >> > > The CFM module doesn't maintain a separate timer for each
> > remote
> > > > MP.
> > > > > >> > > Instead it maintains one timer that triggers at an interval
> > of 3.5
> > > > > >> > > times the transmission interval.  When the CFM module
> > receives a
> > > > CCM
> > > > > >> > > from a remote MP, it sets a flag for this remote MP
> > indicating the
> > > > > >> > > reception.   When the timer triggers, any MPs which are not
> > > > flagged
> > > > > >> > > are considered unreachable and removed.  All of this
> > information
> > > > (the
> > > > > >> > > timers, the set of reachable MPs, the reception flag) is
> > available
> > > > > >> > > from the ovs-appctl cfm/show command.
> > > > > >> > >
> > > > > >> > > It's also worth noting that we don't implement the full
> > 802.1ag
> > > > > >> > > specification.  We implement a much simplified version which
> > > > maintains
> > > > > >> > > the packet format, but is quite a bit less sophisticated than
> > the
> > > > > >> > > standard.
> > > > > >> > >
> > > > > >> > > Ethan
> > > > > >> > >
> > > > > >> > >
> > > > > >> > >
> > > > > >> > > >
> > > > > >> > > >
> > > > > >> > > > Ed- this command shows the configured CFM,my doubt was when
> > CCM
> > > > > >> received
> > > > > >> > > > then timer gets restarted then how can I check /verfiy this
> > that
> > > > > >> timer
> > > > > >> > > has
> > > > > >> > > > been restarted for a MP or MPs
> > > > > >> > > >>
> > > > > >> > > >>
> > > > > >> > > >> Ethan
> > > > > >> > > >>
> > > > > >> > > >>
> > > > > >> > > >>
> > > > > >> > > >> >
> > > > > >> > > >> > Regards,
> > > > > >> > > >> > Ed
> > > > > >> > > >> >
> > > > > >> > > >> > _______________________________________________
> > > > > >> > > >> > discuss mailing list
> > > > > >> > > >> > discuss at openvswitch.org
> > > > > >> > > >> > http://openvswitch.org/mailman/listinfo/discuss
> > > > > >> > > >> >
> > > > > >> > > >
> > > > > >> > > >
> > > > > >> > >
> > > > > >>
> > > > > >> > _______________________________________________
> > > > > >> > discuss mailing list
> > > > > >> > discuss at openvswitch.org
> > > > > >> > http://openvswitch.org/mailman/listinfo/discuss
> > > > > >>
> > > > > >>
> > > > > >
> > > >
> >



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