1. Anoop Ghanwani Linda Dunbar Mike McBride Vinay Bannai Ramki Krishnan
Framework for Application-specific Multicast in NVO3 draft-ghanwani-nvo3-app-mcast-framework-01
Anoop Ghanwani
Linda Dunbar
Mike McBride
Vinay Bannai
Ramki Krishnan
draft-ghanwani-nvo3-app-mcast-framework-01

2. draft-ghanwani-nvo3-app-mcast-framework-01
Overview
Motivation
Types of multicast traffic
Mechanisms for multicast in NVO3
Impact to NVO3 control plane for supporting application-specific multicast
draft-ghanwani-nvo3-app-mcast-framework-01

3. draft-ghanwani-nvo3-app-mcast-framework-01
Motivation
Document various multicast mechanisms in NVO3 networks
The NVO3 underlay may or not deploy IP multicast
Highlight issues and considerations of each mechanism
Discuss impact of application-specific multicast to the NVO3 control plane protocol
draft-ghanwani-nvo3-app-mcast-framework-01

4. Types of Multicast Traffic
ARP/ND
Application multicast
Source-specific multicast (s,G)
Any-source multicast (*,G)
draft-ghanwani-nvo3-app-mcast-framework-01

5. Mechanisms for Multicast in NVO3
No multicast
Replication at the source NVE
Replication at a multicast service node
IP multicast in the underlay
Other methods
Not discussed further in this draft
draft-ghanwani-nvo3-app-mcast-framework-01

6. draft-ghanwani-nvo3-app-mcast-framework-01
No Multicast
Use an NVA to obtain end station information
No ARP/ND
NVE responds to ARP from the TS
Network does not need to be multicast capable
No good way to register non-virtualized hosts
No support for multicast applications
draft-ghanwani-nvo3-app-mcast-framework-01

7. No Multicast Control Plane Impact
NVE must be configured to handle ARP Request/Reply for all hosts/VNs that it participates in
L2 address learning not necessary
Application multicast not supported
draft-ghanwani-nvo3-app-mcast-framework-01

8. Replication at the Source NVE
Source NVE creates copies for all destination NVEs
Copies are delivered by unicast
Network does not need to be multicast capable
Scalability concerns
Forwarding performance of NVE
Redundant copies on shared links
draft-ghanwani-nvo3-app-mcast-framework-01

9. Replication at the Source NVE Control Plane Impact
NVA must configure NVE with addresses of all remote NVEs for each VNI
Unknowns and multicast traffic would be sent to that set of NVEs
NVE may snoop IGMP Joins to optimize multicast
If this is done, then NVEs must be aware when any group member moves
L2 address learning may be used
draft-ghanwani-nvo3-app-mcast-framework-01

10. Replication at a Multicast Service Node
Multicast packets are unicast to replication node
Replication node creates copies and unicasts them to destination NVEs
Network does not need to be multicast capable
Scalability concerns
Forwarding performance of replication node
Redundant copies on shared links from replication node
RPF / MAC address learning
draft-ghanwani-nvo3-app-mcast-framework-01

11. Replication at MSN Control Plane Impact
NVA must configure NVE to send unknown, multicast traffic to MSN in addition to local TSs
MSN can optimize delivery based on knowledge of NVEs participating in a VNI and snooping IGMP messages
MSN must have knowledge of VNI membership and can snoop
MSN could function as IGMP querier
L2 address learning cannot be used
At least not without some hacks
draft-ghanwani-nvo3-app-mcast-framework-01

12. IP Multicast in the Underlay
IP multicast is used in the underlay
PIM-SM
BIDIR PIM
IGMP/MLD Snooping
Ensures optimal delivery
Scalability concerns
Must use a different “outer” multicast address for each tenant multicast address
State in the network for multicast traffic
BIER may help
draft-ghanwani-nvo3-app-mcast-framework-01

13. IP Multicast in the Underlay Control Plane Impact
NVA must configure the NVE with which undelay group address to use for each VNI
To optimize multicast, a separate underlay address would be required for each tenant multicast group
L2 address learning may be used
draft-ghanwani-nvo3-app-mcast-framework-01

14. draft-ghanwani-nvo3-app-mcast-framework-01
Summary & Next Steps
There are many ways to achieve multicast transport in an NVO3 network
All of them have been used in different pre-standard implementations
The mechanisms are described and the pros and cons of each are discussed
Impact to the NVO3 control plane is discussed for each of the mechanisms
Ready to become a WG document?
draft-ghanwani-nvo3-app-mcast-framework-01

15. draft-ghanwani-nvo3-app-mcast-framework-01
Thank you
draft-ghanwani-nvo3-app-mcast-framework-01