Service Manual

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 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:
• The system saves all the dynamic ND cache entries to a database on the flash 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 specific to IPv6 are performed:
• If a database of dynamic ND entries is present on the flash, 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 flushed, if not learnt again). The
database on the flash 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 configured to be as high as necessary. Dell recommends that you configure the
reachable timer to be 90 seconds or longer.
Flex Hash and Optimized Boot-Up 327