Advertising TE Link Information

Context

Nodes on an MPLS network use OSPF TE to exchange TE link attributes such as bandwidth and colors to generate TEDBs. TEDB information is used by CSPF to calculate paths for MPLS TE tunnels. Current, the device can use two methods to advertise TE information to generate TEDBs.

OSPF TE

OSPF TE is an OSPF extension used on an MPLS TE network. LSRs on the MPLS area exchange Opaque Type 10 LSAs that carry TE link information to generate TEDBs for CSPF calculation.

OSPF areas do not support TE by default. The OSPF Opaque capability must be enabled to support OSPF TE, and a node can generate Opaque Type 10 LSAs only if at least one OSPF neighbor is in the Full state.

If OSPF TE is disabled, no Opaque Type 10 LSA is generated or exchanged by nodes to generate TEDBs. On an OSPF TE-incapable network, CR-LSPs are established using OSPF routes but not CSPF calculation results.
IS-IS TE

IS-IS TE is an IS-IS extension used on an MPLS TE network. IS-IS TE defines a new TLV in Link State Packets (LSPs) and IS-IS TE-enabled nodes send these LSPs to flood and synchronize TE link information. IS-IS TE extracts TE link information from LSPs and then transmits the TE link information to the CSPF module for calculating tunnel paths.

Use the mode in which TE information is advertised according to the IGP used on the backbone network. Perform the following operations on each node of an MPLS TE tunnel.

Procedure

Configure OSPF TE.
1. Run system-view
  The system view is displayed.
2. Run ospf [ process-id ]
  The OSPF view is displayed.
3. Run opaque-capability enable
  The OSPF Opaque capability is enabled.
4. (Optional) Run advertise mpls-lsr-id
  The node is enabled to advertise an MPLS LSR ID to multiple OSPF areas.
  
  This step is performed only on an area border router (ABR) connected to multiple OSPF areas.
5. Run area area-id
  The OSPF area view is displayed.
6. Run mpls-te enable [ standard-complying ]
  MPLS TE is enabled in the OSPF area.
Configure IS-IS TE.
1. Run system-view
  The system view is displayed.
2. Run isis [ process-id ]
  The IS-IS view is displayed.
3. Run cost-style { compatible [ relax-spf-limit ] | wide | wide-compatible }
  The IS-IS wide metric function is enabled.
  
  IS-IS TE uses sub-TLVs of the IS reachability TLV (type 22) to carry TE link information. The IS-IS wide metric must be configured to support the IS reachability TLV. The IS-IS wide metric supports the wide, compatible, and wide-compatible metric types. By default, IS-IS sends and receives LSPs with narrow metric values.
4. Run traffic-eng [ level-1 | level-2 | level-1-2 ]
  IS-IS TE is enabled.
  
  By default, TE is not enabled for IS-IS processes.
  
  If no IS-IS level is specified, the node is a Level-1-2 device that can generate two TEDBs for communicating with Level-1 and Level-2 devices.