Traffic Engineering Bandwidth And Bandwidth Pools; Path Option Switchover - Cisco ASR 9000 Series Configuration Manual

Path Option Attributes
In this example, the attribute-set named MYSET is specifying affinity as 0xBEEF. The signalled bandwidth
has not been configured in this MYSET. The tunnel 10, meanwhile, has affinity 0xCAFE configured. LSPs
computed from path-option 1 uses the affinity 0xBEEF/0xBEEF, while LSPs computed from path-option 2
uses the affinity 0xCAFE/0xCAFE. All LSPs computed using any of these path-options use
signalled-bandwidth as 1000, as this is the only value that is specified only at the tunnel level.
The attributes configured in a path option attribute-set template takes precedence over the same attribute
Note
configured under a tunnel. An attribute configured under a tunnel is used only if the equivalent attribute
is not specified by the in-use path option attribute-set template.
Related Topics
Configuring Attributes within a Path-Option Attribute, on page 242

Traffic Engineering Bandwidth and Bandwidth Pools

MPLS traffic engineering allows constraint-based routing (CBR) of IP traffic. One of the constraints satisfied
by CBR is the availability of required bandwidth over a selected path. Regular TE tunnel bandwidth is called
the global pool. The subpool bandwidth is a portion of the global pool. If it is not in use, the subpool
bandwidth is not reserved from the global pool. Therefore, subpool tunnels require a priority higher than that
of non-subpool tunnels.
You can configure the signalled-bandwidth path option attribute to use either the global pool (default) or the
subpool bandwidth. The signalled-bandwidth value for the path option may be any valid value and the pool
does not have to be the same as that which is configured on the tunnel.
When you configure signalled-bandwidth for path options with the signalled-bandwidth bandwidth
Note
[sub-pool | global] kbps command, use either all subpool bandwidths or all global-pool bandwidth values.
Related Topics
Configuring Attributes within a Path-Option Attribute, on page 242

Path Option Switchover

Reoptimization to a particular path option is not possible if the in-use path option and the new path option do
not share the same bandwidth class. The path option switchover operation would fail in such a scenario. Use
this command at the EXEC configuration mode to switchover to a newer path option :
mpls traffic-eng switchover tunnel-xx ID path-option index
The switchover to a newer path option is achieved, in these instances:
• when a lower index path option is available
• when any signalling message or topology update causes the primary LSP to go down
• when a local interface fails on the primary LSP or a path error is received on the primary LSP
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Implementing MPLS Traffic Engineering
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