What are three physical interface properties?（）

多项选择题Which two commands allow you to return to a previous verision of software on the device?（）

A. request sytem software add
B. request sytem software downgrade
C. request sytem software replace
D. request sytem software rollback

单项选择题Which statement is true regarding the Junos OS?（）

A. Each process runs in its own protected memory space ensuring that one process cannot directly interface with another
B. Process share memory space but separate ASICs so that one process cannot directly interfere with another
C. A central processor called the IP2 chip dynamically assings memory as process needs fluctuate
D. The memory management daemon (mmd) is responsible for allocating new memory for process as they request it