Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 626)

602 Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide
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IS-IS shortcuts
5
This command sets the relative metric value to -5. The LSP cost is determined by subtracting 5
from the native IGP cost to reach the tunnel destination. Using this example, when the native IGP
cost is 10, the relative metric value -5 sets the LSP cost to 5.
NOTE
The shortcut cost is never a value less than 1. For example, when the native IGP cost is 10 and the
relative metric is -15, the shortcut cost is 1, not -5.
Syntax: [no] shortcuts isis level1 | level2 relative-metric + | – num
Enter the [no] form of the command to return to the default native IGP path metric. IS-IS shortcuts
are still enabled. The [no] form of the command simply removes the relative-metric value from the
configuration.
The + or – sign is required. + denotes a positive number. – denotes a negative number.
For num, enter a value from 1 – 16777215. The default is zero (0).
The metric used in the SPF calculation is displayed in the output of the show isis shortcuts
command. When the LSP tunnel is not used in the SPF calculation, a – (dash) is displayed in the
SPF metric field.
Example configurations
This section includes example configurations and relevant show command outputs both before and
after IS-IS shortcuts are enabled.
The following display shows an IS-IS route configuration before IS-IS shortcuts are installed.
Brocade(config-mpls-lsp-tomu3)# show ip route isis
Type Codes - B:BGP D:Connected I:ISIS O:OSPF R:RIP S:Static; Cost - Dist/Metric
ISIS Codes - L1:Level-1 L2:Level-2
OSPF Codes - i:Inter Area 1:External Type 1 2:External Type 2 s:Sham Link
Destination Gateway Port Cost Type Uptime
1 0.0.0.0/0 10.1.1.2 eth 1/1 115/21 IL2 0m23s
2 10.2.1.0/24 10.1.1.2 eth 1/1 115/20 IL2 0m23s
3 10.3.1.0/24 10.1.1.2 eth 1/1 115/10 IL2 0m23s
4 10.4.1.1/32 10.1.1.2 eth 1/1 115/10 IL2 0m23s
5 10.2.2.2/32 10.1.1.2 eth 1/1 115/10 IL2 0m23s
6 10.1.0.0/16 DIRECT drop 115/10 IL1 3m37s
7 10.2.1.1/32 10.1.1.2 eth 1/1 115/20 IL2 0m23s
.
The following example shows IS-IS shortcut configuration.
Brocade(config-mpls)# lsp tomu3
Brocade(config-mpls-lsp-tomu3)# metric 1
Brocade(config-mpls-lsp-tomu3)# shortcuts isis level2
Brocade(config-mpls-lsp-tomu3)# enable
Connecting signaled LSP tomu3
The following display shows the IS-IS route configuration after the shortcut configuration is applied.
The bold text indicates that the routes are now using shortcuts. Compare this output with the
output generated before the shortcut configuration was applied.