Which two are characteristics of RSVP?()
A. RSVP itself provides bandwidth and delay guarantees.
B. For RSVP to be end-to-end, all devices must support RSVP.
C. RSVP reservations are maintained by a centralized reservations server.
D. An RSVP compatible QoS mechanism must be used to implement guarantees according to RSVP reservations.
正确答案：参考B, D
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