Administrator Guide
ports to be 10-Gigabit Ethernet interfaces and 8 ports as 40-Gigabit Ethernet interfaces. You must congure 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 ash drive.
A le is generated to indicate that the system is undergoing a fast boot, which is used after the system comes up.
After the Dell 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 ash 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 ushed if not learnt again). The database on the ash 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 conguration is not considered (only during the initial period when the peer comes up).
If you do not congure BGP GR, you must congure 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, trac disruption occurs from that point onwards, even if the system continues to maintain valid routing
information in the hardware and is capable of forwarding trac.
LACP and IPv6 Routing
The following IPv6-related actions are performed during the reload phase:
• The system saves all the dynamic ND cache entries to a database on the ash card. After the system comes back online, and the Dell
Networking OS image is loaded and the corresponding software applications on the system are also activated, the following processes
specic to IPv6 are performed:
• If a database of dynamic ND entries is present on the ash, the information is read and the ND entries are restored (to the IPv6
subsystem as well as the kernel); the entries are installed on the switch as quickly as possible. At the same time, the entries are
changed to an initial (“incomplete”) state so that they are refreshed (and ushed, if not learnt again). The database on the ash is also
deleted immediately.
• To ensure that the adjacent systems do not time out and purge their ND cache entries, the age-out time or the reachable time for ND
cache entries must be congured to be as high as necessary. Dell recommends that you congure the reachable timer to be 90
seconds or longer.
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Flex Hash and Optimized Boot-Up