Flexible Name-Based Tunnel Constraints - Cisco ASR 9000 Series Configuration Manual

Flexible Name-based Tunnel Constraints

• path-selection ignore overload mid
• path-selection ignore overload tail
• path-selection ignore overload
For more information related to IS-IS overload avoidance related commands, see Cisco ASR 9000 Series
Aggregation Services Router MPLS Command Reference.
Related Topics
Configuring the Ignore Integrated IS-IS Overload Bit Setting in MPLS-TE, on page 182
Configure the Ignore IS-IS Overload Bit Setting in MPLS-TE: Example, on page 254
Flexible Name-based Tunnel Constraints
MPLS-TE Flexible Name-based Tunnel Constraints provides a simplified and more flexible means of
configuring link attributes and path affinities to compute paths for MPLS-TE tunnels.
In the traditional TE scheme, links are configured with attribute-flags that are flooded with TE link-state
parameters using Interior Gateway Protocols (IGPs), such as Open Shortest Path First (OSPF).
MPLS-TE Flexible Name-based Tunnel Constraints lets you assign, or map, up to 32 color names for affinity
and attribute-flag attributes instead of 32-bit hexadecimal numbers. After mappings are defined, the attributes
can be referred to by the corresponding color name in the command-line interface (CLI). Furthermore, you
can define constraints using include, include-strict, exclude, and exclude-all arguments, where each statement
can contain up to 10 colors, and define include constraints in both loose and strict sense.
You can configure affinity constraints using attribute flags or the Flexible Name Based Tunnel Constraints
Note
scheme; however, when configurations for both schemes exist, only the configuration pertaining to the
new scheme is applied.
Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide, Release 4.3.x
126
The tunnels stay up if set-overload-bit is set by IS-IS on the head router. Ignores overload during CSPF
for LSPs originating from an overloaded node. In all other cases (mid, tail, or both), the tunnel stays
down.
The tunnels stay up if set-overload-bit is set by IS-IS on the mid router. Ignores overload during CSPF
for LSPs transiting from an overloaded node. In all other cases (head, tail, or both), the tunnel stays
down.
The tunnels stay up if set-overload-bit is set by IS-IS on the tail router. Ignores overload during CSPF
for LSPs terminating at an overloaded node. In all other cases (head, mid, or both), the tunnel stays
down.
The tunnels stay up irrespective of on which router the set-overload-bit is set by IS-IS.
When you do not select any of the options, including head nodes, mid nodes, and tail
Note
nodes, you get a behavior that is applicable to all nodes. This behavior is backward
compatible in nature.
Implementing MPLS Traffic Engineering
OL-28381-02