Which transport layer protocol is used to form LDP sessions?
Which transport layer protocol is used to form LDP sessions?
The transport layer protocol used to form LDP (Label Distribution Protocol) sessions is TCP. TCP is a connection-oriented protocol that ensures reliable communication, which is essential for maintaining the sessions in LDP. Sessions in LDP involve the exchange of various messages that require guaranteed delivery and proper sequencing, which are characteristics provided by TCP.
Key word here is 'sessions' UDP is connectionless and can be ruled out. TCP is the answer. The other two are just there to throw you off. RDP? really?
"LDP uses User Datagram Protocol (UDP) and TCP to transport the protocol data unit (PDU) that carries LDP messages"
c win this question.
The given answer is correct
Sessions are formed using UDP
Ignore that, UDP are used for the initial hello. Session Establishment After two LSRs exchange LDP discovery Hello messages, they start the process of session establishment, which proceeds in two sequential phases: Transport connection establishment Session initialization The objective of the transport connection establishment phase is to establish a reliable TCP connection between two LDP peers. If both LDP peers initiate an LDP TCP connection, it might result in two concurrent TCP connections. To avoid this situation, an LSR first determines whether it should play the active or passive role in session establishment by comparing its own transport address with the transport address it obtains through the exchange of LDP Hellos. If its address has a higher value, it assumes the active role. Otherwise, it is passive. When an LSR plays the active role, it initiates a TCP connection to the LDP peer on the well-known LDP TCP port 646.
LDP discovery messages uses UDP. Session messages use TCP
C is correct