Label Distribution And Control - HP 10500 Series Configuration Manual

Figure 15 Dynamically establishing an LSP

Label distribution and control

Label advertisement modes
Figure 16 Label advertisement modes
DU mode
Ingress
DoD mode
LDP advertises label-FEC mappings in one of the following ways:
Downstream Unsolicited (DU) mode—Unsolicitedly distributes FEC-label mappings to the upstream
•
LSR, without waiting for label requests. The device supports only the DU mode.
• Downstream on Demand (DoD) mode—Sends a label request for a FEC to the downstream LSR.
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.
2) Unsolicitely distributes a label
mapping for the FEC to the
upstream.
Transit
1) Sends a label request for a
FEC to the downstream.
4) Distributes a label mapping for
the FEC to the upstream upon
receiving the request.
1) Unsolicitely distributes a label
mapping for a FEC to the upstream.
Egress
2) Sends a label request for the
FEC to the downstream.
3) Distributes a label mapping for
the FEC to the upstream upon
receiving the request.
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