I understand the stack as follows:
iStack and CSS are two different virtual technologies. CSS is generally used for frame-shaped devices, such as S12704 CE12804, and iStack is generally used for case-shaped devices, such as S5720 CE6650. Of course, their configurations are not same.
A simple configuration example is as follows，I hope you like:
#
#configure the stack S5720LI-1
stack slot 0 renumber 1
stack slot 0 priority 200
#
interface stack-port 0/1
port interface gigabitethernet 0/0/21 to gigabitethernet 0/0/24 enable
quit
#
#configure the stackS5720HI-2
stack slot 0 renumber 2
stack slot 0 priority 100
#
interface stack-port 0/2
port interface gigabitethernet 0/0/21 to gigabitethernet 0/0/24 enable
quit
#
#3. save the configuration and reboot the device
#4. Connect stack cables to set up a stack
#
#
# On CE6850-01, set the stack member ID to 1, priority 150 and stack domain ID to 10.
system-view
sysname DC-TOR-01
commit
stack
stack member 1 priority 150
stack member 1 domain 10
quit
commit
interface stack-port 1/1
port member-group interface 40ge 1/0/5 to 1/0/6
y
quit
commit
quit
#
# On CE6850-02, set the stack member ID to 2 and stack domain ID to 10.
system-view
sysname DC-TOR-02
commit
stack
stack member 1 priority 120
stack member 1 domain 10
stack member 1 renumber 2 inherit-config
y
quit
commit
interface stack-port 1/2
port member-group interface 40ge1/0/5 to 1/0/6
y
quit
commit
quit
#Save the configurations of CE6800-1 and CE6800-2, power off CE6800-1 and CE6800-2, connect the stack link, and power on CE6800-1 and CE6800-2.
#
#
#CSS configuration
configure the CSS
1. Connect CSS cables
2. S12704-01
#
system-view
sysname S12704-01
set css mode css-card
set css id 1
set css priority 100
#
3. S12704-02
system-view
sysname S12704-02
set css mode css-card
set css id 2
set css priority 10
#
4. Run the Command css enable and the device will automatically restart.
[S12704-01]css enable
[S12704-02]css enable
#
#
#
sysname DC_R1&R2_CS_S12704
#
interface gigabitethernet 1/1/0/47
mad detect mode direct
y
quit
#
interface gigabitethernet 2/1/0/47
mad detect mode direct
y
quit
#
#
.
