Label Distribution And Control - HP MSR2000 Configuration Manual

Figure 9 Dynamically establishing an LSP

Label distribution and control

Label advertisement modes
Figure 10 Label advertisement modes
LDP advertises label-FEC mappings in one of the following ways:
Downstream Unsolicited (DU) mode—Distributes FEC-label mappings to the upstream LSR, without
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waiting for label requests. The device supports only the DU mode.
Downstream on Demand (DoD) mode—Sends a label request for an FEC to the downstream LSR.
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After receiving the label request, the downstream LSR distributes the FEC-label mapping for that FEC
to the upstream LSR.
NOTE:
A pair of upstream and downstream LSRs must use the same label advertisement mode. Otherwise, the
LSP cannot be established.
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