Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 68)

44 Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide
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Auto-bandwidth for RSVP LSPs
1
Brocade(config-mpls-lsp-xyz)# auto-bandwidth
Brocade(config-mpls-lsp-xyz-auto-bandwidth)# min-bandwidth 600
Syntax: [no] min-bandwidth value
The value parameter specifies that the LSP bandwidth can never be lower than this value. The
range is from 0 through 2147483647 kbps. The default value is 0 kbps.
The [no] option sets the corresponding parameter value to the default.
Underflow-limit
Current provision for premature bandwidth adjustment is available only for the case when the
actual traffic rate is found to be consistently greater that the current bandwidth. The opposite case
where the actual traffic rate is much less than the reserved bandwidth is not handled. This may
result in very long periods of over-provisioned bandwidth. In order to avoid this, a new parameter
called the underflow-limit is provided. This parameter can be configured along the same lines as
overflow-limit. This parameter is configurable on an auto-bandwidth template as well as an LSP.
The same inheritance rules as other parameters applies.
Suppose the underflow-limit is set to 10. When 10 consecutive samples of the LSP traffic rate are
found to be lesser than the LSP bandwidth by an amount more than the threshold, a premature
adjustment is triggered setting the LSP bandwidth to the maximum of these 10 consecutive
samples. The sampled-rate chosen as the new bandwidth for the LSP is the maximum of those 10
samples that triggered the underflow. If adjustment-threshold is configured to use the
autobw-threshold-table, the threshold from the auto-bandwidth table is used. Unlike overflow-limit,
the number of underflow counts is not reset after adjustment-interval expiry. This means that out of
the 10 samples that triggered the adjustment, six may be the beginning samples of current
adjustment period while the remaining four may be the last samples of the previous adjustment
period.
Configuring overflow limit to enable premature adjustment
The automatic bandwidth adjustment timer is a periodic timer that is triggered at every adjustment
interval to determine whether any bandwidth adjustments are required on the LSPs. This interval is
configured as a long period of time, usually a number of hours. If, at the end of an adjustment
interval, the change in bandwidth is above an certain adjustment threshold, the LSP is resignaled
with the new bandwidth.
During every adjustment interval, the device samples the average bandwidth utilization of an LSP
and, when this has exceeded the current maximum average bandwidth utilization, the maximum
average bandwidth utilization is updated.
Overflow-limit allows for adjusting the bandwidth without waiting for the adjustment-timer to expire.
When the sampled traffic rate is found to be greater than the current bandwidth and exceeding the
threshold, consecutively, for a number of times configured as overflow-limit, bandwidth adjustment
is triggered using the maximum sampled bandwidth in the current adjustment interval.
To specify a limit on the number of bandwidth overflow samples before triggering an automatic
bandwidth allocation adjustment, enter the following commands.
Brocade(config-mpls-lsp-xyz)# auto-bandwidth
Brocade(config-mpls-lsp-xyz-auto-bandwidth)# overflow limit 5