Cisco ASR 900 Series User Manual

Multi Path” (ECMP). In this scenario, path calculation must use other tiebreakers (such as, node hop
count and path minimum bandwidth) to select one path. Max-fill is a tiebreaker method that selects from
all ECMPs, a path with the least head room, but can still accommodate the path request. This method
has the effect of packing the links. Min-fill is a tiebreaker method that selects from all ECMPs, a path
with the most head room, and which has a load balance effect over time.
• Restore path option – The restore path option signals a restore LSP after the double failure of both,
primary and protect LSPs.
Flex LSP SRLG and Exclude Option for Explicit Path
Use the following commands to configure SRLG on an interface:
Router(config)# interface Ethernet0/1
Router(config-if)# srlg gid <1-4294967295>
SRLG values configured on MPLS TE enabled interfaces are flooded through IGP (IS-IS or OSPF), and are
used by MPLS TE in the following scenarios:
•
Automatically create backup tunnels to avoid SRLGs of their protected interfaces (MPLS TE FRR).
Router(config)# mpls traffic-eng static backup srlg exclude [force | preferred]
•
Restrict protection path to avoid SRLGs of links in the working path.
Router(config)# interface Tunnel100
Router(config-if)# tunnel mpls traffic-eng path-option protect 1 diverse
srlg [node] lockdown
•
Exclude SRLG in IP Explicit Path.
Router(config)# ip explicit-path name EXAMPLE
Router(cfg-ip-expl-path)# exclude-srlg A.B.C.D
The exclude-srlg command specifies an address to get SRLGs from for exclusion.
For bidirectional co-routed LSP, both ends of the tunnel must be configured with the same exclude options
in explicit path. Otherwise, it is considered a configuration error.
Note
Only 32 SRLG values can be configured on an interface. Also, MPLS TE only accepts up to 400 SRLG
values configured on a system.
Note
Configuring Flex LSP SRLG and Exclude Option
On the MPLS-TE enabled interface:
!
interface GigabitEthernet0/3/0
srlg gid 10
srlg gid 20
srlg gid 30
srlg gid 40
srlg gid 50
ip address 102.103.1.1 255.255.255.0
ip ospf 1 area 0
negotiation auto
MPLS Basic Configuration Guide, Cisco IOS XE Everest 16.5.1 (Cisco ASR 900 Series)
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Flex LSP Overview
Flex LSP SRLG and Exclude Option for Explicit Path

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English