What are two characteristics of dual-ring interconnect in SONET networks? （）(Choose two.)

• A、It protects signals against node failures between rings.
• B、It protects signals against node failure within a single ring.
• C、It allows for traffic to be preempted when a ring switch occurs.
• D、Traffic can be dropped and continued at interconnecting nodes.
• E、It protects preemptible traffic from being dropped when a ring switch occurs.