Before discussing the CE-LDP, lets explaint “constraint-based routing” term.
“Contraint-based Routing” is the routing which in which the routing process is done according to some constraints. Both QoS-based routing and policy-based routing belong to Contraint-based Routing. As you know these routing include QoS constraints or policy constraints.
CR-LDP (constraint-based LDP) contains extensions for LDP. And with these extensions, Contraint-based Routing is supported on LDP. In other words, Contraint-based Routing brings Traffic Engineering(TE) mechanism to the LDP.
The additional TLV parameters are new for CR-LDP:
For more information about LDP, T-LDP and CR-LDP, check the related following RFCs…
Value Parameter ----- --------- 821 LSPID 822 ResCls 503 Optical Session Parameters 800 Explicit Route 801-804 ER-Hop TLVS 810 Traffic Parameters 820 Preemption 823 Route Pinning 910 Optical Interface Type 920 Optical Trail Desc 930 Optical Label 940 Lambada SetMPLS Label Distribution Protocol, LDP – Part 1 MPLS Label Distribution Protocol, LDP – Part 2 MPLS Label Distribution Protocol, LDP – Part 3 (Configuration on ALU) MPLS Label Distribution Protocol, LDP – Part 4 (ECMP) MPLS Label Distribution Protocol, LDP – Part 5 (Export and Import Policy, Prefix Aggregation) MPLS Label Distribution Protocol, LDP – Part 6 (T-LDP) MPLS Label Distribution Protocol, LDP – Part 7 (CR-LDP)
RFC 5036: LDP Specification RFC 3815: Definitions of Managed Objects for the MPLS,LDP RFC 3478: Graceful Restart Mechanism for Label Distribution Protocol RFC 5443: LDP IGP Synchronization RFC 7307: LDP Extensions for Multi-Topology RFC 7361: LDP Extensions for Optimized MAC Address Withdrawal in a H-VPLS RFC 3212: Constraint-Based LSP Setup using LDP RFC 3213: Applicability Statement for CR-LDP RFC 3214: LSP Modification Using CR-LDP…YOU CAN REACH ALL THE “MPLS” ARTICLES AND CONFIGURATIONS BELOW… MPLS Basics What is MPLS? Enabling MPLS on Cisco Router MPLS Label Distribution Protocol, LDP MPLS Label Distribution Protocol, LDP – Part 1 MPLS Label Distribution Protocol, LDP – Part 2 MPLS Label Distribution Protocol, LDP – Part 3 (Configuration on ALU) MPLS Label Distribution Protocol, LDP – Part 4 (ECMP) MPLS Label Distribution Protocol, LDP – Part 5 (Export and Import Policy, Prefix Aggregation) MPLS Label Distribution Protocol, LDP – Part 6 (T-LDP) MPLS Label Distribution Protocol, LDP – Part 7 (CR-LDP) MPLS, RSVP-TE MPLS, RSVP-TE – Part 1 MPLS, RSVP-TE – Part 2(Alcatel-Lucent Configuration) MPLS Protection And Restoration MPLS Protection and Restoration – Part 1 MPLS Protection and Restoration – Part 2 (End-to-End Protection, Secondary Paths) MPLS Protection and Restoration – Part 3 (Path Diversity in Secondary Paths) MPLS Protection and Restoration – Part 4 (Local Protection, Fast Reroute) MPLS Protection and Restoration – Part 5 (Fast Reroute Protection Types) MPLS Protection and Restoration – Part 6 (RSVP Objects Used for MPLS Fast Reroute) MPLS Protection and Restoration – Part 7 (Verification Commands on Alcatel-Lucent Routers) MPLS Protection and Restoration – Part 8 (Actions After the Failure) MPLS Protection and Restoration – Part 9 (Convergence Factors) MPLS Protection and Restoration – Part 10 (Juniper Configuration Samples) MPLS Protection and Restoration – Part 11 (Juniper Configuration Samples) MPLS Protection and Restoration – Part 12 (Juniper Configuration Samples) MPLS Protection and Restoration – Part 13 (Juniper Configuration Samples)