Which two statements are true about DPT/RPR?

A.
DPT/RPR uses a bi-directional ring consisting of two symmetric counter rotating fibre rings.

B.
DPT/RPR is defined in the IEEE 802.17 standard and it uses Token Bucket system to avoid
collisions on the fiber.

C.
DPT/RPR can be deployed in the Core of the SP networks where point-to-point POS links are
used to make best use of the Bandwidth.

D.
In DPT/RPR rings, data packets can be sent in one direction (downstream) and the
corresponding control packets in the opposite direction (upstream), thus using both fibres
concurrently to maximize bandwidth.

Explanation:
• SONET/SDH is the accepted transport architecture.
• The key building block is the twin optical fiber ring forming point-to-point connections that are
“nailed up” between several SONET/SDH add-drop multiplexers (ADM).
• The twin fiber rings in SONET/SDH ring run in parallel, one is the working ring carrying the
communication traffic. The other is the protection ring acting as a backup in the event of cable
failure or failure of an ADM node.
• SONET/SDH provides good quality performance monitoring and failure protection information
which also travel along the ring.
• The exclusive use of one ring for data and the other for protection means one ring is fully utilized

and the other ring is virtually redundant, awaiting the unlikely event of a failure.
This, of course, is not the most efficient use of fiber, especially given the considerable cost to lay
fiber.