Cisco ASR 900 Series User Manual

Associated Bidirectional Co-routed LSPs: A co-routed bidirectional TE LSP denotes a bidirectional tunnel
where the forward direction LSP and reverse direction LSP must follow the same path, for example, the same
nodes and paths. Here is an illustration.
In the above topology:
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Paths at the top of the figure (in green) indicate working co-routed LSP pairs.
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Paths at the bottom of the figure (in red) indicate protecting co-routed LSP pairs.
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Router 1 sets up working LSP to Router 3 (in red) after performing bidirectional CSPF and sends reverse
explicit route object (ERO) to Router 3. Node Router 3 uses the received reverse ERO to set up reverse
red working LSP to Router 1.
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Router 3 sets up protecting LSP to Router 1 (in green) after performing bidirectional CSPF and sends
reverse ERO to Router 1. Node Router 1 uses the received reverse ERO to set up reverse green protecting
LSP to Router 3.
Restrictions for Flex LSP
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Exp-null over Flex-LSP is not supported.
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Flex-LSP does not support tunnel statistics.
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VC (layer 2 VPN ckts) statistics are not supported.
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It is recommended to configure for the following timers for Flex-LSP deployments:
mpls traffic-eng reoptimize timers frequency 120
mpls traffic-eng reoptimize timers delay installation 30
mpls traffic-eng reoptimize timers delay cleanup 90
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The no mpls ip propagate-tcl command is not recommended with Flex-LSP. The PREC value of BFD
control packet is set to “0”. Therefore, packet prioritization cannot be done at mid-points and BFD flap
can occur with traffic congestions.
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It is recommended to configure BFD timers as 10x3 during cable pull testing or in Flex LSP feature
deployments.
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50 msec convergence is not guaranteed for local shut.
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50 msec convergence is not guaranteed without WRAP protection. WRAP protection is mandatory to
achieve 50 msec convergence for remote failures.
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With scale and multiple other feature mix-up, it is possible to see higher convergence.
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TE NSR and IGP NSR are mandatory for RSP switchover.
MPLS Basic Configuration Guide, Cisco IOS XE Everest 16.5.1 (Cisco ASR 900 Series)
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Flex LSP Overview
Restrictions for Flex LSP

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English