Reference Guide

• The system delays sending the BGP End-of-RIB notification to peers with whom BGP GR has been
negotiated to ensure that the local routes of the system are advertised to the peers, if required by the
configuration.
• If BGP GR is enabled on any peering session, the timeout values used for the BGP hold timer do not
take effect.
Cold Boot Caused by Power Cycling the System
When you perform a power-cycle operation on a system that is configured with the optimized booting
functionality, the system goes through its regular boot sequence even if it is configured for fast boot.
When the system comes up, it is expected that there will be no dynamic ARP or ND database to restore.
The system boot up mode will not be fast boot and
Unexpected Reload of the System
When an unexpected or unplanned reload occurs, such as a reset caused by the software, the system
performs the regular boot sequence even if it is configured for fast boot. When the system comes up,
dynamic ARP or ND database entries are not present or required to be restored. The system boot up
mode will not be fast boot and actions specific to this mode will not be performed.
Software Upgrade
When fast boot is used to upgrade the system to a release that supports fast boot, the system enables the
restoration of dynamic ARP or ND databases that were maintained in the older release from when you
performed the upgrade and the ARP and ND applications identify that the system has been booted using
fast boot.
LACP Fast Switchover
For fast boot, the operation of LACP has been optimized. These LACP optimizations are applicable even
when fast boot is not enabled when a system reload is performed. These enhancements are controlled
using the fast-switchover option that is available with the lacp command in Port Channel Interface
Configuration mode. When LACP ‘fast-switchover’ is enabled on the system, two optimizations are
performed to the LACP behavior:
• The wait-while timer is not started in the ‘waiting’ state of the MUX state machine. The port moves
directly to the ‘attached’ state.
• The local system moves to the ‘collecting’ and ‘distributing’ states on the port in a single step without
waiting for the partner to set the ‘collecting’ bit.
Changes to BGP Multipath
When the system becomes active after a fast-boot restart, a change has been made to the BGP multipath
and ECMP behavior. The system delays the computation and installation of additional paths to a
destination into the BGP routing information base (RIB) and forwarding table for a certain period of time.
Additional paths, if any, are automatically computed and installed without the need for any manual
intervention in any of the following conditions:
• After 30 seconds of the system returning online after a restart
• After all established peers have synchronized with the restarting system
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Flex Hash and Optimized Boot-Up