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Bug 2042952

Summary: [RFE] Support multicast (IGMP/MLD) in OVN interconnection
Product: Red Hat Enterprise Linux Fast Datapath Reporter: Dumitru Ceara <dceara>
Component: OVNAssignee: Dumitru Ceara <dceara>
Status: CLOSED CURRENTRELEASE QA Contact: ying xu <yinxu>
Severity: medium Docs Contact:
Priority: high    
Version: FDP 21.KCC: ctrautma, dcbw, jiji, jishi
Target Milestone: ---Keywords: FutureFeature
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: ovn22.06-22.06.0-4.el8fdp ovn22.06-22.06.0-4.el9fdp Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2023-03-13 07:16:58 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Dumitru Ceara 2022-01-20 11:49:59 UTC 
Description of problem:

When OVN deployments are interconnected using ovn-ic, if:

(1) IGMP/MLD snooping is enabled within the different AZs

and

(2) the logical routers in each AZ have multicast relay and flooding of the reports towards the transit switch enabled

and

(3) the transit switch has IGMP/MLD snooping enabled

IP multicast traffic with destination G, originated by VIFs in an AZ don't reach VIFs that registered for receiving IP multicast traffic for group G in a different AZ.

Additional info:
A potential solution is to:
(1) fix multicast report static forwarding in the router pipeline (it currently decrements TTL and drops IGMP reports).
(2) for transit switches add another flow in the egress pipeline (executed on the remote AZ) to ensure that IGMP packets are punted to ovn-controller in both the local and remote AZs.
Comment 1 Dan Williams 2022-02-24 20:19:53 UTC 
(1) was accepted upstream: http://patchwork.ozlabs.org/project/ovn/list/?series=281827&state=%2A&archive=both
Comment 2 Dumitru Ceara 2022-02-28 21:11:22 UTC 
Patch posted for review: https://mail.openvswitch.org/pipermail/ovs-dev/2022-February/392083.html
Comment 3 Dumitru Ceara 2022-03-01 13:50:48 UTC 
v1 on patchwork: http://patchwork.ozlabs.org/project/ovn/list/?series=288441&state=*
Comment 4 Dumitru Ceara 2022-03-03 10:08:40 UTC 
v2 on patchwork: http://patchwork.ozlabs.org/project/ovn/list/?series=288742&state=*
Comment 5 Dumitru Ceara 2022-05-19 10:45:40 UTC 
Patch accepted upstream, will be available in the first ovn22.06 release.