[ovs-discuss] openvswitch-2.5.0 IGMP-SNOOPING question
my_ovs_discuss at yahoo.com
my_ovs_discuss at yahoo.com
Thu Oct 27 22:03:37 UTC 2016
Haven't gotten any response for this so far.
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From: "my_ovs_discuss at yahoo.com" <my_ovs_discuss at yahoo.com>
To: Thadeu Lima de Souza Cascardo <cascardo at redhat.com>
Cc: Discuss <discuss at openvswitch.org>
Sent: Monday, October 3, 2016 3:56 PM
Subject: Re: [ovs-discuss] openvswitch-2.5.0 IGMP-SNOOPING question
Yes, Linux bridge querier.
Topology is attached in the pdf.
-Thanks.
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From: Thadeu Lima de Souza Cascardo <cascardo at redhat.com>
To: my_ovs_discuss at yahoo.com
Cc: Discuss <discuss at openvswitch.org>
Sent: Monday, October 3, 2016 3:41 PM
Subject: Re: [ovs-discuss] openvswitch-2.5.0 IGMP-SNOOPING question
On Mon, Oct 03, 2016 at 09:17:00PM +0000, my_ovs_discuss at yahoo.com wrote:
> Thanks Cascardo for the response.
> The problem is IGMP querier in Linux kernel sends queries with source IP 0.0.0.0 and this is being ignored by OVS.Since the current implementation of mcast-snooping in OVS isn't really tracking the source IP of queriers, can we relax this source IP 0.0.0.0check for queries?
> Thanks
>
Do you mean the Linux bridge querier? What is your topology? Do you want OVS to
forward the queries from Linux bridge or something like that?
Cascardo.
>
>
>
> Sent from Yahoo Mail. Get the app
>
> From: Thadeu Lima de Souza Cascardo <cascardo at redhat.com>
> To: my_ovs_discuss at yahoo.com
> Cc: Discuss <discuss at openvswitch.org>
> Sent: Monday, October 3, 2016 7:20 AM
> Subject: Re: [ovs-discuss] openvswitch-2.5.0 IGMP-SNOOPING question
>
> On Fri, Sep 30, 2016 at 01:25:08AM +0000, my_ovs_discuss at yahoo.com wrote:
> > Hi, openvswitch-2.5.0 seems to ignore IGMP queries with source IP 0.0.0.0
> > But, RFC seems to say the following: Highlighted in red.
> > That switches shouldn't drop queries with source IP 0.0.0.0.
>
> The highlighted section mentions IGMP *MEMBERSHIP REPORTS*, not queries. That
> section refers to switches that implement proxy reporting, which OVS doesn't.
> OVS, however, does not add to the list of multicast routers the ports where IGMP
> queries with source address 0.0.0.0 arrives (unless queries with other source
> addresses arrive, that is). That is in complicance with this same quote, see
> item B below.
>
> Did you mean that queries with source address 0.0.0.0 are not forwarded? In that
> case, OVS will look at the destination address and send only to those ports that
> belong to that multicast group. If it's a membership report, OVS will send only
> to ports belonging to multicast routers.
>
> Does this behavior you see cause any real problem? Like some multicast traffic
> not reaching some destinations?
>
> Regards.
> Cascardo.
>
> >
> > RFC 4541 IGMP and MLD Snooping Switches Considerations May 2006
> >
> >
> > This is not a problem in an IGMPv3-only network because there is
> > no suppression of IGMP Membership reports.
> >
> > The administrative control allows IGMP Membership Report messages
> > to be processed by network monitoring equipment such as packet
> > analyzers or port replicators.
> >
> > The switch supporting IGMP snooping must maintain a list of
> > multicast routers and the ports on which they are attached. This
> > list can be constructed in any combination of the following ways:
> >
> > a) This list should be built by the snooping switch sending
> > Multicast Router Solicitation messages as described in IGMP
> > Multicast Router Discovery [MRDISC]. It may also snoop
> > Multicast Router Advertisement messages sent by and to other
> > nodes.
> >
> > b) The arrival port for IGMP Queries (sent by multicast routers)
> > where the source address is not 0.0.0.0.
> >
> > The 0.0.0.0 address represents a special case where the switch
> > is proxying IGMP Queries for faster network convergence, but is
> > not itself the Querier. The switch does not use its own IP
> > address (even if it has one), because this would cause the
> > Queries to be seen as coming from a newly elected Querier. The
> > 0.0.0.0 address is used to indicate that the Query packets are
> > NOT from a multicast router.
> >
> > c) Ports explicitly configured by management to be IGMP-forwarding
> > ports, in addition to or instead of any of the above methods to
> > detect router ports.
> >
> > 2) IGMP networks may also include devices that implement "proxy-
> > reporting", in which reports received from downstream hosts are
> > summarized and used to build internal membership states. Such
> > proxy-reporting devices may use the all-zeros IP Source-Address
> > when forwarding any summarized reports upstream. For this reason,
> > IGMP membership reports received by the snooping switch must not
> > be rejected because the source IP address is set to 0.0.0.0.
> >
> > -Thanks
>
> > _______________________________________________
> > discuss mailing list
> > discuss at openvswitch.org
> > http://openvswitch.org/mailman/listinfo/discuss
>
>
>
>
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