Up to seven Flex-Algorithms in the range 128 to 255 can be configured for IS-IS. Use the participate command to configure participation for the specific algorithm. If a locally configured FAD exists, advertise this definition by using the advertise command. A router is not required to advertise a configured FAD to participate in a Flex-Algorithm.
If a router has enabled Flex-Algorithms to participate or advertise the FAD, it is configured and active for all configured IS-IS areas.
Use the following syntax to configure Flex-Algorithms for IS-IS:
config>router>isis
— flexible-algorithms
— [no] flex-algo flex-algo
— advertise fad-name
— no advertise
— [no] loopfree-alternates
— [no] participate
— [no] shutdown
The following is an example configuration output for Flex-Algorithm participation:
isis 0
flexible-algorithms
flex-algo 128
advertise "My128"
participate
exit
no shutdown
exit
The following output is an example of IS-IS router capability when a FAD is advertised:
*A:Dut-B# show router isis database Dut-B.00-00 detail level 2
===============================================================================
Rtr Base ISIS Instance 0 Database (detail)
===============================================================================
Displaying Level 2 database
-------------------------------------------------------------------------------
LSP ID : Dut-B.00-00 Level : L2
Sequence : 0x94 Checksum : 0x4ae0 Lifetime : 969
Version : 1 Pkt Type : 20 Pkt Ver : 1
Attributes: L1L2 Max Area : 3 Alloc Len : 1492
SYS ID : 4900.0000.0002 SysID Len : 6 Used Len : 223
TLVs :
Supp Protocols:
Protocols : IPv4
IS-Hostname : Dut-B
Router ID :
Router ID : 10.20.1.2
Router Cap : 10.20.1.2, D:0, S:0
TE Node Cap : B E M P
SR Cap: IPv4 MPLS-IPv6
SRGB Base:20000, Range:10001
SR Alg: metric based SPF, 128
Node MSD Cap: BMI : 12 ERLD : 15
FAD Sub-Tlv:
Flex-Algorithm : 128
Metric-Type : delay
Calculation-Type : 0
Priority : 100
Flags: M