multicast considerations for gateway initiated dual-stack lite...
DESCRIPTION
IP-Multicast Deployment with GI-DS-lite GI-DS-lite only applies to IPv4-Unicast traffic: IPv4-Multicast forwarding does not change –If Gateway loses IPv4-Multicast connectivity while deploying GI-DS-lite: Establish a tunnel between Gateway and appropriate IP-Multicast router –Switching to AFTR as first-hop router (e.g. in case Gateway has only IPv6 connectivity) would change multicast forwarding on Gateway and challenge AFTR & network scalability GI-DS-lite allows for overlapping IPv4 addresses on Access-Devices –Typically no additional considerations required, e.g. architectures like BBF TR-101 even contain IGMP proxies, where IGMP packets are sourced with –For deployments with IGMPv3 and a requirement for explicit tracking, an identifier other than the Source-IPv4 address of the IGMP packets needs to be used (see also I-D.ietf-multimob-pmipv6-base-solution) Access Device IGMP Proxy Gateway Access Device IPv4-Multicast Network IP-Multicast Source AFTR Only IPv4-Unicast Deployment exampleTRANSCRIPT
Multicast Considerations for Gateway Initiated Dual-Stack lite
(draft-brockners-softwire-mcast-gi-ds-lite-00)
Authors:Frank Brockners ([email protected]), Yiu L. Lee ([email protected])
IETF 79, Beijing
OverviewMulticast in Subscriber Access Networks
• Architectural Characteristics / Assumptions– Access Devices receive, but do not source IP-Multicast traffic– Gateway is first hop IP-Multicast router for Access Devices– Multicast and unicast forwarding paths in the access network (Access-Device to Gateway)
can differ (e.g. due to use of “Multicast VLAN”)– Access network can contain IGMP proxies (to optimize Layer-2 multicast delivery)– Multicast NAT is not considered
AccessDevice
IGMPProxy
GatewayAccessDevice
AccessDevice
IPv4-MulticastNetwork
IPv4-Multicast Source
IPv4-Multicast Source
Deployment example
IP-Multicast Deployment with GI-DS-lite
• GI-DS-lite only applies to IPv4-Unicast traffic: IPv4-Multicast forwarding does not change
– If Gateway loses IPv4-Multicast connectivity while deploying GI-DS-lite: Establish a tunnel between Gateway and appropriate IP-Multicast router
– Switching to AFTR as first-hop router (e.g. in case Gateway has only IPv6 connectivity)would change multicast forwarding on Gateway and challenge AFTR & network scalability
• GI-DS-lite allows for overlapping IPv4 addresses on Access-Devices– Typically no additional considerations required, e.g. architectures like BBF TR-101 even contain IGMP proxies, where IGMP packets are sourced with 0.0.0.0.– For deployments with IGMPv3 and a requirement for explicit tracking, an identifier other than the Source-IPv4 address of the IGMP packets needs to be
used (see also I-D.ietf-multimob-pmipv6-base-solution)
AccessDevice
IGMPProxy
GatewayAccessDevice
AccessDevice
IPv4-MulticastNetwork
IP-Multicast Source
IP-Multicast Source
AFTR
Only IPv4-Unicast
Deployment example
Next steps
• More feedback is much appreciated• Adopt as a WG draft?