Major network vendors (except Cisco) default to the following modes of Label Distribution Protocol (LDP) operation (as per RFC 5036 LDP Specification):
- Label Distribution (Advertisement): Downstream Unsolicited (section 2.6.3)
- Label Control: Ordered (section 2.6.1)
- Label Retention: Liberal (section 2.6.2)
This topic focuses on Ordered Label Distribution Control procedure to help you better understand when LSR actually assigns labels and initiates transmission of a label mapping.