Cisco NCS 5500 Series Configuration Guides

The following example shows how to deactivate IS-IS overload bit avoidance:
config
no mpls traffic-eng path-selection ignore overload
Configuring Global Weighted SRLG Protection
A shared risk link group (SRLG) is a set of links sharing a common resource and thus shares the same risk
of failure. The existing loop-free alternate (LFA) implementations in interior gateway protocols (IGPs) support
SRLG protection. However, the existing implementation considers only the directly connected links while
computing the backup path. Hence, SRLG protection may fail if a link that is not directly connected but shares
the same SRLG is included while computing the backup path. Global weighted SRLG protection feature
provides better path selection for the SRLG by associating a weight with the SRLG value and using the weights
of the SRLG values while computing the backup path.
To support global weighted SRLG protection, you need information about SRLGs on all links in the area
topology. You can flood SRLGs for remote links using ISIS or manually configuring SRLGS on remote links.
Configuration Examples: Global Weighted SRLG Protection
There are three types of configurations that are supported for the global weighted SRLG protection feature.
• local SRLG with global weighted SRLG protection
• remote SRLG flooding
• remote SRLG static provisioning
This example shows how to configure the local SRLG with global weighted SRLG protection feature.
RP/0/RP0/CPU0:router(config)# srlg
RP/0/RP0/CPU0:router(config-srlg)# interface TenGigE0/0/0/0
RP/0/RP0/CPU0:router(config-srlg-if)# name group1
RP/0/RP0/CPU0:router(config-srlg-if)# exit
RP/0/RP0/CPU0:router(config-srlg)# interface TenGigE0/0/0/1
RP/0/RP0/CPU0:router(config-srlg-if)# name group1
RP/0/RP0/CPU0:router(config-srlg)# name group value 100
RP/0/RP0/CPU0:router(config)# router isis 1
RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast
RP/0/RP0/CPU0:router(config-isis-if-af)# fast-reroute per-prefix srlg-protection
weighted-global
RP/0/RP0/CPU0:router(config-isis-if-af)# fast-reroute per-prefix tiebreaker srlg-disjoint
index 1
RP/0/RP0/CPU0:router(config-isis)# interface TenGigE0/0/0/0
RP/0/RP0/CPU0:router(config-isis-if)# point-to-point
RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RP0/CPU0:router(config-isis-if-af)# fast-reroute per-prefix
RP/0/RP0/CPU0:router(config-isis-if-af)# fast-reroute per-prefix ti-lfa
RP/0/RP0/CPU0:router(config-isis)# srlg
RP/0/RP0/CPU0:router(config-isis-srlg)# name group1
RP/0/RP0/CPU0:router(config-isis-srlg-name)# admin-weight 5000
This example shows how to configure the global weighted SRLG protection feature with remote SRLG
flooding.The configuration includes local and remote router configuration. On the local router, the global
weighted SRLG protection is enabled by using the fast-reroute per-prefix srlg-protection weighted-global
command. In the remote router configuration, you can control the SRLG value flooding by using the advertise
Routing Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.3.x
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Implementing IS-IS
Configuring Global Weighted SRLG Protection

Cisco NCS 5500 Series Specifications

General

Series	NCS 5500
Category	Network Router
Operating System	Cisco IOS XR
Product Type	Modular Router
Form Factor	Rack-mountable
Purpose	High-performance routing for service providers and large enterprises
Interface Types	Ethernet
Redundancy	Redundant power supplies and fan trays
Port Density	Varies by model; high-density configurations available
Routing Protocols	BGP, OSPF, IS-IS, MPLS
Power Supply Options	AC and DC power supplies available
Management	CLI, SNMP, NETCONF