Why cannot an LSP session become Up after a TCP connection is established

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After a TCP connection is established, the two ends of the TCP connection negotiate parameters such as label distribution mode (DU or DoD). If negotiation fails, the LSP session cannot become Up.

Other related questions:
Why is no MPLS LSP generated after an MPLS LDP session is established
After a remote MPLS LDP session is established, the corresponding MPLS LSP cannot be generated if MPLS LDP is disabled on some interfaces. When MPLS LDP is disabled on an interface, the remote LDP session can be established. The LSP labels, however, are allocated hop by hop, which requires that MPLS LDP be enabled on all interfaces along the LSP.

What are the reasons for the static LSP's failure in becoming Up
A static LSP is classified into the common static LSP, static LSP bound to the tunnel, and static CR-LSP bound to the tunnel. Switches of V200R002C00 or later support MPLS TE. Each node checks the command configuration of a common static LSP. The common static LSP fails to be configured in any of the following situations: MPLS is not enabled globally. The static LSP with the same name exists. The static LSP with the same destination address and the same outbound interface (next hop) exists. The static LSP with the same incoming label exists. The configured next hop address is not the actual next hop address in the routing table. Each node checks the command configuration of a static LSP bound to the tunnel. The static LSP bound to the tunnel fails to be configured in any of the following situations: MPLS is not enabled globally. MPLS TE is not enabled globally. On the ingress node, the bound tunnel does not exist or is not configured. The static LSP with the same name exists. The static LSP with the same destination address and the same outbound interface (next hop) exists. The static LSP with the same incoming label exists. The configured next hop address is not the actual next hop address in the routing table. Each node checks the command configuration of a static CR-LSP bound to the tunnel. The static CR-LSP bound to the tunnel fails to be configured in any of the following situations: MPLS is not enabled globally. MPLS TE is not enabled globally. On the ingress node, the bound tunnel does not exist or is not configured. The static LSP with the same name exists. The static LSP with the same destination address and the same outbound interface (next hop) exists. The static LSP with the same incoming label exists. The configured next hop address is not the actual next hop address in the routing table.

Why does a TCP connection fail to be established even if ping succeeds
To establish a TCP connection, the server must have a Listening port and the client must initiate a TCP connection. Run the display tcp status command to check whether a Listening port is configured on the server and the client initiates a TCP connection.

How are the server and client determined for establishing a TCP connection
Check the transport addresses used to establish a TCP connection. The larger address is the active end that initiates the TCP connection. It is the client of the TCP connection. The smaller address is the server of the TCP connection.

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