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

Tue Mar 20 01:06:05 UTC 2012

> 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

It isn't possible to tag packets in Open vSwitch 1.2.  In 1.4 you can
tag packets, but they aren't respected on ingress.

Ethan

>
> -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
>> > > > >>
>> > > > >>
>> > > > >
>> > >
>
>