Setup Guide

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.
Interoperation of Applications with Fast Boot and
System States
This functionality is supported on the platform.
The following sections describe the application behavior when fast boot functionality is enabled:
LACP and IPv4 Routing
Prior to the system restart, the system implements the following changes when you perform a fast boot:
The system saves all dynamic ARP entries to a database on the flash drive.
A file is generated to indicate that the system is undergoing a fast boot, which is used after the system comes up.
After the Dell EMC Networking OS image is loaded and activated, and the appropriate software components come up, the following
additional actions are performed:
• If a database of dynamic ARP entries is present on the flash drive, that information is read and the ARP entries are restored; the
entries are installed on the switch as soon as possible. At the same time, the entries are changed to an initial (“aged out”) state so that
they are refreshed (and flushed if not learnt again). The database on the flash card is also deleted instantaneously.
• The system ensures that local routes known to BGP are imported into BGP and advertised to peers as quickly as possible. In this
process, any advertisement-interval configuration is not considered (only during the initial period when the peer comes up).
If you do not configure BGP GR, you must configure the peering with BGP keepalive and hold timers to be as high as possible (depending
on your network deployment and the scaled parameters or sessions) to enable the connection to be active until the system re-initializes
the switch, causing the links to adjacent devices to go down. If the BGP sessions are disabled before the re-initialization of the switch
occurs because of the peer timing out, traffic disruption occurs from that point onwards, even if the system continues to maintain valid
routing information in the hardware and is capable of forwarding traffic.
LACP and IPv6 Routing
The following IPv6-related actions are performed during the reload phase:
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Flex Hash and Optimized Boot-Up