Which two statements are true about IS -IS routing?（）
- A Based on the default timers, OSPF d etects a failure faster than IS - IS does.
- B OSPF default timers permit more tuning than IS - IS does.
- C IS - IS is more efficient than OSPF in the use of CPU resources.
- D OSPF is more scalable than IS - IS because of its ability to identify normal, stub, an d NSSA areas.
- E IS - IS and OSPF are both Open Standard, link - state routing protocols which support VLSM.