Alcatel-Lucent 7750 SR OS, Interface Configuration Manual

Page: 154 / 444

Configuring Ports
Page 154 7750 SR OS Interface Configuration Guide
• The published switchover times for bundle protection groups on the 7750 are dependent
on the far end being able to recover from cell loss within that time. To ensure this, the
following recommendations are given:
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The BPGrp link activation timer should be configured to a value small enough to
allow a quick recovery from any IMA failure occurring during the switchover. A
recommended value is 1 second.
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The ADM that terminates APS should support standard APS switchover time
requirements.
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The far end IMA/MLPPP links must be able to tolerate cell loss during APS
switchover without bringing links down. This includes, for example, a combination
of link activation/deactivation and appropriate configuration of TDM/SONET
debounce timers.
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Because of the temporary cell loss during the APS switchover, the far end IMA/
MLPPP will experience a misalignment between individual links within an IMA/
MLPPP group. The far end IMA/MLPPP group must support fast-realignment of
links without having to bring the links down. The 7750 synchronizes the IMA/
MLPPP streams the far end receives between switchovers in an effort to cause the
least amount of misalignment.
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To increase the BPGrp robustness, it is recommended to provision more IMA/MLPPP
links than is required and set the minimum links and max bandwidth parameters to the
number of required links. This type of configuration is required on the far end as well.