Overview
The MBSTF can use either Object distribution method or Packet distribution method for providing streams of packets sent to multicast/broadcast services. So far we have implemented several Object distribution method based operating modes, which implement object based FLUTE sessions.
The Packet distribution method is used to push data to streams based on UDP packets by either forwarding encapsulated packets or by proxying application layer UDP data.
For both packet operating modes the processing of the packets passes through a similar processing chain:
TS 26.502 Figure 4.3.3.3-1: MBSTF architecture overview for Packet Distribution Method
Forward-only mode
In this mode packets are ingested at reference point Nmb8 as encapsulated multicast/broadcast UDP packets inside unicast UDP packets.
The encapsulated packets may then be optionally modified to add FEC.
The resulting multicast packets are scheduled for transmission down the UPF UDP tunnel at reference point Nmb9 as encapsulated packets.
- Packet ingester - This provides a unicast listening port for accepting encapsulated UDP packets.
- Application Layer FEC - This is optional and may modify the encapsulated IP and UDP headers in order to add FEC, the encapsulated UDP payload is left unmodified.
- Packetisation - This does nothing but pass through the packet (with FEC if applicable).
- Packet scheduling - This schedules the encapsulated packet using the MBR provided in the Distribution Session.
Proxy mode
In this mode unicast or multicast UDP packets are ingested at reference point Nmb8:
- Unicast ingest: MBSTF provides an endpoint to which the packets sent by the Application Provider.
- Multicast ingest: MBSTF subscribes to the multicast provided by the Application Provider).
In all cases:
- The IP and UDP header of ingested packets are replaced with values configured for the Distribution Session at Nmb2.
- FEC is optionally added.
The resulting multicast packets are scheduled for transmission down the UPF UDP tunnel at reference point Nmb9 as encapsulated packets.
- Packet ingester - This provides a unicast listening port for accepting UDP payloads or subscribes to a multicast session to receive the UDP payloads.
- Application Layer FEC - This is optional and may supplement the payload with FEC.
- Packetisation - This adds an IP and UDP header to form an encapsulated UDP packet.
- Packet scheduling - This schedules the encapsulated packet using the MBR provided in the Distribution Session.
Overview
The MBSTF can use either Object distribution method or Packet distribution method for providing streams of packets sent to multicast/broadcast services. So far we have implemented several Object distribution method based operating modes, which implement object based FLUTE sessions.
The Packet distribution method is used to push data to streams based on UDP packets by either forwarding encapsulated packets or by proxying application layer UDP data.
For both packet operating modes the processing of the packets passes through a similar processing chain:
TS 26.502 Figure 4.3.3.3-1: MBSTF architecture overview for Packet Distribution Method
Forward-only mode
In this mode packets are ingested at reference point Nmb8 as encapsulated multicast/broadcast UDP packets inside unicast UDP packets.
The encapsulated packets may then be optionally modified to add FEC.
The resulting multicast packets are scheduled for transmission down the UPF UDP tunnel at reference point Nmb9 as encapsulated packets.
Proxy mode
In this mode unicast or multicast UDP packets are ingested at reference point Nmb8:
In all cases:
The resulting multicast packets are scheduled for transmission down the UPF UDP tunnel at reference point Nmb9 as encapsulated packets.