Users Guide

from Release 9.3(0.0) to an earlier release that does not support the fast boot functionality because the
system behavior is unexpected and undefined.
• Fast boot uses the Symmetric Multiprocessing (SMP) utility that is enabled on the Intel CPU on the
device to enhance the speed of the system startup. SMP is supported on the device.
For the fast boot feature to reduce the traffic disruption significantly, the following conditions apply:
1 When LACP is used between the ToR switch and the adjacent devices, LACP is configured on these
adjacent devices with a timeout value of 90 seconds or longer.
2 BGP timers between the ToR switch and adjacent devices are set to high values (for example, a hold
timeout of 180 seconds) unless BGP graceful restart is used.
3 Before performing the planned reload, we recommend that the IPv6 Neighbor Discovery (ND) reachable
timer is increased to a value of 300 seconds or longer on the adjacent devices to prevent the ND cache
entries from becoming stale and being removed while the ToR goes through a CPU reset. This timer can
be restored to its prior value after the ToR has completed its planned reload.
4 The BGP protocol on the adjacent devices responds to network (link-state) changes and route
advertisements quickly and propagates these further up the network quickly. You might need to adjust
the BGP timers on these devices.
5 Note that fast boot will operate even if some of the preceding conditions are not met. However, the
duration of traffic loss might be longer.
6 Warm boot is supported because it enables faster convergence and reduced traffic loss.
7 BGP graceful restart must be configured with GR time left to default (120 seconds) or higher. The BGP
hold timer should be configured as 10 seconds.
8 You must configure the LACP long timeout, which is the amount of time that a LAG interface waits for a
PDU from the remote system before bringing the LACP session down, to be higher than the default
value.
9 Traffic from North-South and South-North nodes are of line rate type.
10 Traffic outage for a planned reboot is less than 30 seconds for 4000 routes of IPv4 and IPv6 traffic for all
of the following traffic directions.
• South-North
• North-South
• East-West
• West-East
To the south of ToR switch, 96 servers can be linked. Up to 8 Multiprocotol BGP (MP-BGP) sessions to the
servers are established. You can configure a minimum of 2 MP-BGP sessions and a maximum of 8 MP-BGP
sessions.
To the north of the ToR switch, up to 8 leaf nodes are connected. Up to 8 EBGP sessions for IPv4 and IPv6 for
each leaf node are configured. LACP is enabled between the ToR and leaf nodes, and the LACP long timer is
set to the default value. You must configure 96 ports to be 10-Gigabit Ethernet interfaces and 8 ports as 40-
Gigabit Ethernet interfaces. You must configure the switch to operate with an uplink speed of 40 Gigabit
Ethernet per second.
Flex Hash and Optimized Boot-Up 357