Dell Unity™ All Flash and Unity Hybrid Hardware Information Guide

Link control card functions and features

The LCC supports, controls, and monitors the DAE, and is the primary interconnect management element. Each LCC includes connectors for input and output to downstream devices.

The LCCs in a DAE connect to the storage processors and other DAEs. The cables connect the LCCs in a system in a daisy chain topology.

Internally, each DAE LCC uses protocols to emulate a loop; it connects to the drives in its enclosure in a point-to-point fashion through a switch. The LCC independently receives and electrically terminates incoming signals. For traffic from the system's storage processors, the LCC switch passes the signal from the input port to the drive being accessed; the switch then forwards the drive output signal to the port.

Each LCC has four ports marked AA/A and BB/B. The A and B ports are used when connecting (A) or expanding (B) using x4 lane cables. The AA/A and BB/B ports are both used when connecting (AA/A) or expanding (BB/B) using x8 lane cabling.

Each LCC independently monitors the environmental status of the entire enclosure, using a microcomputer-controlled monitor program. The monitor communicates the status to the storage processor, which polls disk enclosure status. LCC firmware also controls the SAS Phys and the disk-module status LEDs.

An enclosure ID, sometimes referred to as the enclosure address (EA), indicator is located on each LCC. Each LCC also includes a bus (back-end port) identification indicator. The SP initializes the bus ID when the operating system is loaded.

NOTE:Some LCCs may not have the enclosure ID display () or back-end bus display (). These LCCs are functionally identical to LCCs with the enclosure ID display and back-end bus display. LCCs with displays always replace LCCs without displays.

3U, 80-drive DAE LCC connectors and LEDs

Each 3U, 80-drive DAE LCC contains the following ports, LEDs, and connectors:

Table 1. 12-Gb/s LCC ports, LEDs and connectors

Location	Description
	12-Gb/s mini SAS ports
	Mini SAS port status LED
	Enclosure ID display
	LCC fault LED
	LCC power LED
	Back-end (BE) bus ID display a
	LCC management port (RJ-12) (not used)

Table 2. 12 Gb/s LCC LEDs

LED	Location	Color	State	Description
Mini SAS port status LED		Blue	On	SAS port linked up
		Green	On	Powered on
		-	Off	No connector in port
LCC fault LED		Amber	On	Fault within the LCC
		-	Off	No fault or powered off
LCC power LED		Green	On	Powered on and no fault
		-	Off	Powered off