The Sequencer module detects whether there are any other service orders for the same customer in the provisioning flow. If multiple orders for a customer exist, the module serializes them so that the system is provisioning only one service order per customer. When the current service order reaches a TokenRemover module, the service order at the top of the queue is allowed to continue in the provisioning flow.
Sequencers automatically checkpoint the incoming service orders (see also Checkpointing Service Orders). Therefore, it is never necessary to place a checkpoint module immediately before or after a Sequencer.
TokenRemovers automatically checkpoint the incoming service orders (see also Checkpointing Service Orders). Therefore, it is never necessary to place a checkpoint module immediately before or after a TokenRemover.
