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multiple access
Table of content
⚠️ TODO: This page needs to be updated.
As described in the carriers page, OpenSAND groups several carriers in categories.
Each terminal is assigned to one of these categories, and is allowed to use only its carriers.
On a star topology, OpenSAND allows the user to configure, for each carrier of a category on the return link, the access type among the following:
- if the return link standard is DVB-RCS2, DAMA and SCPC;
- if the return link standard is DVB-RCS, DAMA, SALOHA and SCPC. TODO does not exist anymore ?
On a mesh topology, OpenSAND allows the following access types:
- if the return link standard is DVB-RCS2, DAMA;
- if the return link standard is DVB-RCS, DAMA and SALOHA. TODO does not exist anymore ?
Moreover, OpenSAND allows the user to configure the access type used for each QoS FIFO of each terminal. Thus, each packet that a terminal must send with a QoS will be sent using the access type of this QoS. The carrier which will transmit the packet is selected by an internal mechanism of the terminal depending on the access type.
Therefore, a terminal could use multiple access types.
The configuration of the multiple access on the return link on a star topology (uplink on a mesh topology) of a terminal has to be set on each carrier, then on the QoS FIFOs of its terminal.
Every carrier has a specific access type among DAMA, Slotted Aloha and CRDSA and SCPC.
The available access types are automatically updated in function of the global configuraiton.
For more information about the terminal assignment to a specific category, please consult the carriers page.
Every terminal has a specific QoS FIFOs configuration. The access type is one item of this configuration.
The SCPC case is a specific case.
Probes of the acces type are specific to it.
For more information, please consult the dedicated page of each access type.
The multiple access is developed on the block DVB, and is configured with the OpenSAND Manager in the configuration files.
The assignment of the access type to a carrier is implemented in the TerminalCategory class, CarrierGroup class and all their derived classes.
The application of the DAMA and SCPC access types is implemented in the DamaCtrl and DamaAgent classes and in the different schedulers (ReturnScheduling, ScpcScheduling...).
The application of the SALOHA access type is implemented in the SalohaNcc and SalohaTal classes.
These classes are handled on the BlockDvbTal, SpotUpwardTransp, SpotDownwardTransp ans SpotDownwardRegen main classes.