多项选择题
A. 成本低
B. 透明性，传输业务种类多；(Transparent and various types of transmission service)
C. 简单，集成度高；(Simple and highly integrated)
D. 具有保护；(With the protection function)
E. 没有保护；(Without the protection function)
F. 最高速率可达10G (The highest rate can reach 10G)