Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two.)（）

• A、It is locally significant.
• B、It is globally significant.
• C、It is needed to identify a unique instance of an OSPF database.
• D、It is an optional parameter required only if multiple OSPF processes are running on the router.
• E、All routers in the same OSPF area must have the same process ID if they are to exchange routing information.