Which two statements are correct about RSVP path messages? (Choose two.)
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A. B. C. D.BC
RSVP (Resource Reservation Protocol) is a signaling protocol used by routers to establish a path for traffic in a Multiprotocol Label Switching (MPLS) network. RSVP uses Path messages and Reservation messages to establish and maintain the LSPs (Label Switched Paths) used to forward the traffic.
Regarding the RSVP path messages, the correct statements are:
A. They are sent by the egress router upstream: This statement is incorrect. RSVP Path messages are sent by the ingress router downstream to the egress router. The Path message contains the characteristics of the traffic flow and the required resources, and it is used to request the establishment of an LSP from the ingress router to the egress router.
B. They are sent by the ingress router downstream: This statement is correct. RSVP Path messages are sent by the ingress router downstream towards the egress router. The Path message is used to reserve the resources for the LSP and to establish the label-switched path.
C. They are used to create an LSP: This statement is partially correct. The RSVP Path message is used to request the establishment of an LSP, but it is not used to create the LSP. The LSP is created when the Path message reaches the egress router and a corresponding Reservation message is sent back to the ingress router.
D. They are used to reserve resources for an LSP: This statement is correct. The RSVP Path message is used to request the reservation of resources for the LSP, such as bandwidth, delay, and jitter, based on the QoS (Quality of Service) requirements of the traffic flow. The Reservation message sent back by the egress router confirms the reservation of resources and establishes the LSP.
In summary, the correct statements about RSVP Path messages are: