Users Guide

Pre-Configuring a Stack Unit Slot
You may also pre-configure an empty stack unit slot with a logical stack unit.
To pre-configure an empty stack unit slot, use the following command.
• Pre-configure an empty stack unit slot with a logical stack unit.
CONFIGURATION mode
stack-unit unit_id provision S4820T
Example of Viewing a Logical Configuration of a Pre-Configured Stack Unit
After creating the logical stack unit, you can configure the interfaces on the stack unit as if it is present.
Dell#show system stack-unit 1
-- Unit 1 --
Unit Type : Member Unit
Status : not present
Dell#con
Dell(conf)#stack-unit 1 provision S4820T
Dell(conf)#end
Dell#show system stack-unit 1
-- Unit 1 --
Unit Type : Member Unit
Status : not present
Required Type : S4820T - 52-port GE/TE/FG (SE)
Dell#
Dell(conf)#interface tengigabitethernet 1/0
Dell(conf-if-te-1/0)#
Removing a Provisioned Logical Stack Unit
To remove the line card configuration, use the following command.
• To remove a logical stack-unit configuration, use the following command:
CONFIGURATION mode
no stack-unit unit_id provision
Hitless Behavior
Hitless is a protocol-based system behavior that makes a stack unit failover on the local system transparent to remote systems.
The system synchronizes protocol information on the Management and Standby stack units such that, in the event of a stack
unit failover, it is not necessary to notify the remote systems of a local state change.
Hitless behavior is defined in the context of a stack unit failover only.
• Only failovers via the CLI are hitless. The system is not hitless in any other scenario.
Hitless protocols are compatible with other hitless and graceful restart protocols. For example, if hitless open shortest path first
(OSPF) is configured over hitless the link aggregation control protocol (LACP) link aggregation groups (LAGs), both features
work seamlessly to deliver a hitless OSPF-LACP result. However, to achieve a hitless end result, if the hitless behavior involves
multiple protocols, all protocols must be hitless. For example, if OSPF is hitless but bidirectional forwarding detection (BFD) is
not, OSPF operates hitlessly and BFD flaps upon an RPM failover.
The following protocols are hitless:
High Availability (HA) 342