The Root System Domain (RSD) is the JUNOS software running on a pair of redundant Routing Engines on a T-series routing platform connected to the switch fabric on the JCS 1200 platform. The configuration on these Routing Engines provides:
Because you can connect up to three T-series routing platforms to the JCS 1200 chassis, you can configure up to three RSDs. The PSD identifiers must be unique for each RSD. That is, PSD1 can only belong to RSD1, and not to RSD2 or RSD3.