Which two statements are true about RSVP and the InServ QoS model？（）
- Aa drawback of implementing RSVP is the requirement to migrate to a supporting routing protocol
- BRSVP uses DSCP to signal QoS requirements to routers
- CRSVP is a routing protocol
- DRSVP is an IP protocol that uses IP protocol ID 46， and TCP/UDP ports 3455
- ERSVP specifically provides a level of service for rate-sensitive and delay-sensitive traffic
- Fthe flow-based approach of RSVP is ideal for large， scalable implementations such as the public internet