ports to be 10-Gigabit Ethernet interfaces and 8 ports as 40-Gigabit Ethernet interfaces. You must configure the switch to operate with anuplink speed of 40 Gigabit Ethernet per second.Interoperation of Applications with Fast Boot andSystem StatesThis functionality is supported on the platform.The following sections describe the application behavior when fast boot functionality is enabled:LACP and IPv4 RoutingPrior 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 additionalactions 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 entriesare 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 arerefreshed (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 thisprocess, 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 (dependingon your network deployment and the scaled parameters or sessions) to enable the connection to be active until the system re-initializes theswitch, causing the links to adjacent devices to go down. If the BGP sessions are disabled before the re-initialization of the switch occursbecause of the peer timing out, traffic disruption occurs from that point onwards, even if the system continues to maintain valid routinginformation in the hardware and is capable of forwarding traffic.LACP and IPv6 RoutingThe 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 DellNetworking OS image is loaded and the corresponding software applications on the system are also activated, the following processesspecific 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 IPv6subsystem as well as the kernel); the entries are installed on the switch as quickly as possible. At the same time, the entries arechanged to an initial (“incomplete”) state so that they are refreshed (and flushed, if not learnt again). The database on the flash is alsodeleted 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 NDcache entries must be configured to be as high as necessary. Dell recommends that you configure the reachable timer to be 90seconds or longer.332 Flex Hash and Optimized Boot-Up
