H3C S6850 Series User manual

i
Contents
1 Preparing for installation·············································································1
Safety recommendations ···································································································································1
Examining the installation site····························································································································1
Temperature/humidity································································································································2
Cleanliness·················································································································································2
EMI·····························································································································································3
Laser safety················································································································································3
Installation tools ·················································································································································3
2 Installing the switch··················································································2-4
Installing the switch in a 19-inch rack··············································································································2-5
Rack-mounting procedures at a glance ··································································································2-5
Rack-mounting requirements··················································································································2-5
Installation accessories···························································································································2-9
Mounting brackets, chassis rails, and grounding cable installation positions ·······································2-12
Attaching the mounting brackets and chassis rails to the chassis························································2-14
Connecting the grounding cable to the chassis ····················································································2-20
Attaching the slide rails to the rack ·······································································································2-21
Mounting the switch in the rack·············································································································2-22
Grounding the switch ····································································································································2-27
Installing/removing fan trays ·························································································································2-28
Installing a fan tray································································································································2-28
Removing a fan tray······························································································································2-29
Installing/removing power modules···············································································································2-30
Installing a power module ·····················································································································2-30
Removing a power module ···················································································································2-32
Connecting the power cords ·························································································································2-34
Connecting an AC power cord··············································································································2-34
Connecting a DC power cord················································································································2-35
Installing/removing expansion modules········································································································2-35
Installing an expansion module·············································································································2-36
Removing an expansion module···········································································································2-37
Verifying the installation································································································································2-38
3 Accessing the switch for the first time····················································3-39
Setting up the configuration environment ·····································································································3-39
Connecting the console cable·······················································································································3-39
Connecting the mini USB console cable·······································································································3-40
Setting terminal parameters··························································································································3-42
Powering on the switch·································································································································3-42
4 Setting up an IRF fabric·········································································4-44
IRF fabric setup flowchart ·····························································································································4-44
Planning IRF fabric setup······························································································································4-45
Planning IRF fabric size and the installation site···················································································4-45
Identifying the master switch and planning IRF member IDs································································4-45
Planning IRF topology and connections································································································4-46
Identifying physical IRF ports on the member switches········································································4-47
Planning the cabling scheme················································································································4-48
Configuring basic IRF settings······················································································································4-49
Connecting the physical IRF ports················································································································4-49
Accessing the IRF fabric to verify the configuration······················································································4-50
5 Maintenance and troubleshooting··························································5-51
Power module failure ····································································································································5-51
Symptom···············································································································································5-51
Solution·················································································································································5-51

ii
Fan tray failure··············································································································································5-51
Symptom···············································································································································5-51
Solution·················································································································································5-51
Configuration terminal display problems·······································································································5-52
No display ·············································································································································5-52
Garbled display·····································································································································5-52

1
1 Preparing for installation
The H3C S6850 Switch Series and S9850 Switch Series are high-density intelligent 100G access
switches with powerful hardware forwarding capacity and abundant data center features. They are
developed for data centers and high-end campus networks.
The H3C S6850 Switch Series includes the following models:
•
S6850-56HF
•
S6850-2C
The H3C S9850 Switch Series includes the following models:
•
S9850-4C
•
S9850-32H
The switch supports the following ports and FRUs:
•
100G QSFP28 ports, 40G QSFP+ ports, 25GE SFP28 ports, and 10G SFP+ ports.
•
Two 1G management Ethernet ports (one fiber port and one copper port).
•
Removable fan trays in redundancy mode and flexible airflows.
•
Removable power modules in redundancy mode.
Safety recommendations
To avoid any equipment damage or bodily injury caused by incorrect use, read the following safety
recommendations before installation. Note that the recommendations do not cover every possible
hazardous condition.
•
Before cleaning the switch, remove all power cords from the switch. Do not clean the switch
with wet cloth or liquid.
•
Do not place the switch near water or in a damp environment. Prevent water or moisture from
entering the switch chassis.
•
Do not place the switch on an unstable case or desk. The switch might be severely damaged in
case of a fall.
•
Ensure good ventilation of the equipment room and keep the air inlet and outlet vents of the
switch free of obstruction.
•
Connect the yellow-green protection grounding cable before power-on.
•
Make sure the operating voltage is in the required range.
•
To avoid electrical shocks, do not open the chassis while the switch is operating or when the
switch is just powered off.
•
When replacing field replaceable units (FRUs), including power modules and fan trays, wear an
ESD wrist strap to avoid damaging the units.
Examining the installation site
The switch must be used indoors.
Mount your switch in a rack and verify the following items:
•
Adequate clearance is reserved at the air inlet and outlet vents for ventilation.
•
The rack has a good ventilation system.

2
•
Identify the hot aisle and cold aisle at the installation site, and make sure ambient air flows into
the switch from the cold aisle and exhausts to the hot aisle.
•
Identify the airflow designs of neighboring devices, and prevent hot air flowing out of the
neighboring devices from entering the top device.
•
The rack is sturdy enough to support the switch and its accessories.
•
The rack is reliably grounded.
To ensure correct operation and long service life of your switch, install it in an environment that meets
the requirements described in the following subsections.
Temperature/humidity
Maintain appropriate temperature and humidity in the equipment room.
•
Lasting high relative humidity can cause poor insulation, electricity leakage, mechanical
property change of materials, and metal corrosion.
•
Lasting low relative humidity can cause washer contraction and ESD and cause problems
including loose mounting screws and circuit failure.
•
High temperature can accelerate the aging of insulation materials and significantly lower the
reliability and lifespan of the switch.
For the temperature and humidity requirements for the switch, see Hardware Information and
Specifications.
Cleanliness
Dust buildup on the chassis might result in electrostatic adsorption, which causes poor contact of
metal components and contact points. In the worst case, this might shorten the device's lifetime and
even cause communication failure. Table1-1 describes the dust concentration limits in the equipment
room.
Table1-1 Dust concentration limit in the equipment room
Substance Particle diameter Concentration limit
Dust particles ≥0.5 µm ≤3.5 × 106particles/m3
Dust particles ≥5 µm ≤ 3 × 104particles/m3
Dust (suspension) ≤75 µm ≤0.2 mg/m3
Dust (sedimentation) 75 µm to 150 µm ≤1.5 mg/(m2h)
Corrosive gases can accelerate corrosion and aging of metal components. Make sure the corrosive
gases in the equipment room do not exceed the concentration limits as shown in Table1-2.
Table1-2 Harmful gas limits in the equipment room
Gas Average concentration
(mg/m3) Maximum concentration
(mg/m3)
SO20.3 1.0
H2S 0.1 0.5
Cl20.1 0.3
HCI 0.1 0.5
HF 0.01 0.03

3
Gas Average concentration
(mg/m3) Maximum concentration
(mg/m3)
NH31.0 3.0
O30.05 0.1
NOX0.5 1.0
EMI
All electromagnetic interference (EMI) sources, from outside or inside of the switch and application
system, adversely affect the switch in the following ways:
•
A conduction pattern of capacitance coupling.
•
Inductance coupling.
•
Electromagnetic wave radiation.
•
Common impedance (including the grounding system) coupling.
To prevent EMI, use the following guidelines:
•
If AC power is used, use a single-phase three-wire power receptacle with protection earth (PE)
to filter interference from the power grid.
•
Keep the switch far away from radio transmitting stations, radar stations, and high-frequency
devices.
•
Use electromagnetic shielding, for example, shielded interface cables, when necessary.
•
To prevent signal ports from getting damaged by overvoltage or overcurrent caused by lightning
strikes, route interface cables only indoors.
Laser safety
WARNING
!
•
The switch is a Class 1M laser device.
•
Disconnected optical fibers or transceiver modules might emit invisible laser light. Do not stare
into beams or view directly with optical instruments when the switch is operating.
Installation tools
No installation tools are provided with the switch. Prepare the following tools yourself:
•
Phillips screwdriver.
•
ESD wrist strap.
•
Marker.

2-4
2 Installing the switch
CAUTION:
Keep the tamper
-
proof seal on a mounting screw on the chassis cover intact, and if you want to open
the chassis, contact
H3C for permission. Otherwise, H3C shall not be liable for any consequence
caused thereby.
Figure2-1 Hardware installation flow
Start
Install the switch
Ground the switch
Connect power cords
Verify the installation
Turn on the circuit
breakers
Operating correctly? Turn off the circuit
breakers
Troubleshoot the
switch
Install expansion
cards?
Yes
Yes
No
No
Install expansion cards
Operating correctly?
Yes
No
Resolve the
problem
End
Install power modules
Install fan trays

2-5
Installing the switch in a 19-inch rack
Rack-mounting procedures at a glance
Figure2-2 Rack-mounting procedure
NOTE:
If a rack shelf is available, you can put the switch on the rack shelf
and slide the switch to a
position
so that the mounting brackets make close contact with the front rack posts. Then use screws to
secure the mounting brackets to the rack.
Rack-mounting requirements
Figure2-3 S6850-56HF chassis dimensions (mounting brackets installed at the port side,
left-side view)
(1) Power module handle
(2) Mounting bracket
Figure2-4 S6850-56HF chassis dimensions (mounting brackets installed at the power module
side, left-side view)
(1) Power module handle
(2) Mounting bracket
Determine the installation
position (near the power
module side or port side )
for the mounting brackets
Attach the chassis
rails to both sides
of the switch
Connect the
grounding cable to
a grounding point
Attach the mounting
brackets to both
sides of the switch
Attach the slide
rails to the rack Install the switch
in the rack
43.6 mm
(1.72 in)
1
26 mm (1.02 in)
460 mm
(18.11 in)
2
43.6 mm
(1.72 in)
1
26 mm (1.02 in)
460 mm
(18.11 in)
2

2-6
Figure2-5 S6850-2C chassis dimensions (mounting brackets installed at the port side,
left-side view)
(1) Power module handle
(2) Mounting bracket
Figure2-6 S6850-2C chassis dimensions (mounting brackets installed at the power module
side, left-side view)
(1) Power module handle
(2) Mounting bracket
Figure2-7 S9850-4C chassis dimensions (mounting brackets installed at the port side,
left-side view)
(1) Power module handle
(2) Mounting bracket
(3) Cable management bracket
44.2 mm
(1.74 in)
1
26 mm (1.02 in)
660 mm
(25.98 in)
2
44.2 mm
(1.74 in)
1
26 mm (1.02 in)
660 mm
(25.98 in)
2
88.1 mm
(3.47 in)
1
90 mm
(3.54 in)
26 mm (1.02 in)
660 mm
(25.98 in)
3
2

2-7
Figure2-8 S9850-4C chassis dimensions (mounting brackets installed at the power module
side, left-side view)
(1) Cable management bracket
(2) Power module handle
(3) Mounting bracket
Figure2-9 S9850-32H chassis dimensions (mounting brackets installed at the port side,
left-side view)
(1) Power module handle
(2) Mounting bracket
Figure2-10 S9850-32H chassis dimensions (mounting brackets installed at the power module
side, left-side view)
(1) Power module handle
(2) Mounting bracket
Table2-2 Distance requirements between the front and rear rack posts
Switch
model Installation method Chassis dimensions
Distance
between the
front and rear
rack posts
Rack
requirements
S6850-56
HF
Mounting brackets
and long slide rails
(provided)
•Height—43.6 mm
(1.72 in)/1 RU
•Width—440 mm
692 to 853 mm
(27.24 to 33.58
in)
•A minimum of
800 mm (31.50
in) in depth
88.1 mm
(3.47 in)
26 mm (1.02 in)
660 mm
(25.98 in)
90 mm
(3.54 in)
2
1
3
460 mm
(18.11 in)
43.6 mm
(1.72 in)
1 2
26 mm (1.02 in)
43.6 mm
(1.72 in)
460 mm
(18.11 in)
26 mm (1.02 in)
12

2-8
Switch
model Installation method Chassis dimensions
Distance
between the
front and rear
rack posts
Rack
requirements
Mounting brackets
and super-short slide
rails (optional,
chassis rails not
reaching out of the
chassis)
(17.32 in)
•Depth—486 mm
(19.13 in)
460 mm (18.11
in) for the
chassis
26 mm (1.02 in)
for the power
module/fan tray
handles
401 to 565 mm
(15.79 to 22.24
in)
(recommended)
•A minimum of
130 mm (5.12 in)
between the front
rack post and the
front door.
•A minimum of
550 mm (21.65
in) between the
front rack post
and the rear
door.
Mounting brackets
and super-short slide
rails (optional,
chassis rails
reaching out of the
chassis)
499 to 692 mm
(19.65 to 27.24
in)
S6850-2C
Mounting brackets at
the port side •Height—44.2 mm
(1.74 in)/1 RU
•Width—440 mm
(17.32 in)
•Depth—686 mm
(27.01 in)
660 mm (25.98
in) for the
chassis
26 mm (1.02 in)
for the power
module/fan tray
handles
519 to 768 mm
(20.43 to 30.24
in)
•A minimum of
1000 mm (39.37
in) in depth
(recommended)
•A minimum of
130 mm (5.12 in)
between the front
rack post and the
front door.
•A minimum of
750 mm (29.53
in) between the
front rack post
and the rear
door.
Mounting brackets at
the power module
side
S9850-4C
Mounting brackets at
the port side
•Height—88.1 mm
(3.47 in)/2 RU
•Width—440 mm
(17.32 in)
•Depth—776 mm
(33.55 in)
660 mm (25.98
in) for the
chassis
26 mm (1.02 in)
for the power
module/fan tray
handles
90 mm (3.54) for
the mounting
brackets
518 to 923 mm
(20.39 to 36.34
in)
•A minimum of
1000 mm (39.37
in) in depth
(recommended)
•A minimum of
130 mm (5.12 in)
between the front
rack post and the
front door.
•A minimum of
750 mm (29.53
in) between the
front rack post
and the rear
door.
Mounting brackets at
the power module
side
•Height—88.1 mm
(3.47 in)/2 RU
•Width—440 mm
(17.32 in)
•Depth—750 mm
(29.53 in)
660 mm (25.98
in) for the
chassis
90 mm (3.54) for
the mounting
518 to 858 mm
(20.39 to 33.78
in)

2-9
Switch
model Installation method Chassis dimensions
Distance
between the
front and rear
rack posts
Rack
requirements
brackets
S9850-32
H
Mounting brackets
and long slide rails
(provided)
•Height—43.6 mm
(1.72 in)/1 RU
•Width—440 mm
(17.32 in)
•Depth—486 mm
(19.13 in)
460 mm (18.11
in) for the
chassis
26 mm (1.02 in)
for the power
module/fan tray
handles
621 to 853 mm
(24.45 to 33.58
in)
•A minimum of
1000 mm (39.37
in) in depth
(recommended)
•A minimum of
130 mm (5.12 in)
between the front
rack post and the
front door.
•A minimum of
550 mm (21.65
in) between the
front rack post
and the rear
door.
Mounting brackets
and short slide rails
(provided)
401 to 633 mm
(15.79 to 24.92
in)
Installation accessories
Table2-3 Installation accessories
Switch
model
Mounting
brackets
(provided)
Cable
management
brackets Rack mounting rail kit
S6850-56H
F 1U high, one pair. See Figure2-11. N/A
1U high, including one pair of long slide rails and
one pair of chassis rails (provided). See
Figure2-14.
1U high, including one pair of super-short slide
rails and one pair of chassis rails (optional). See
Figure2-16.
S6850-2C 1U high, one pair.
See Figure2-11. N/A 1U high, including one pair of short slide rails and
one pair of chassis rails (provided). See
Figure2-15.
S9850-4C 2U high, one pair.
See Figure2-12.
One pair
(provided). See
Figure2-12.
2U high, including one pair of slide rails and one
pair of chassis rails (provided). See Figure2-17.
S9850-32H 1U high, one pair.
See Figure2-13. N/A
1U high, including one pair of long slide rails and
one pair of chassis rails (provided). See
Figure2-14.
1U high, including one pair of short slide rails and
one pair of chassis rails (optional). See
Figure2-15.

2-10
Figure2-11 Mounting brackets provided with the S6850-56HF and S6850-2C switches
Figure2-12 Mounting brackets provided with the S9850-4C switch
(1) Cable management bracket
(2) Mounting bracket
Figure2-13 Mounting brackets provided with the S9850-32H switch
1 2

2-11
Figure2-14 1U long slide rail and chassis rail
(1) Chassis rail
(2) Long slide rail
Figure2-15 1U short slide rail and chassis rail
Figure2-16 1U super-short slide rail and chassis rail
(1) Chassis rail
(2) Super-short slide rail
Figure2-17 2U slide rail and chassis rail
(1) Chassis rail
(2) Slide rail
12
12
1 2

2-12
Mounting brackets, chassis rails, and grounding cable
installation positions
The switch has one mounting position near the network ports and one mounting position near the
power modules for mounting brackets.
The S6850-56HF switch provides two grounding points: primary grounding point (with a grounding
sign) and auxiliary grounding point, as shown in Figure2-18. The S6850-2C switch provides two
grounding points: primary grounding point (with a grounding sign) and auxiliary grounding point, as
shown in Figure2-19. The S9850-4C switch provides three grounding points: primary grounding
point (with a grounding sign), auxiliary grounding point 1, and auxiliary grounding point 2, as shown
in Figure2-20. The S9850-32H switch provides two grounding points: primary grounding point (with a
grounding sign) and auxiliary grounding point, as shown in Figure2-21.
Select installation positions for the mounting brackets, chassis rails, and grounding cable as
required.
Figure2-18 Mounting brackets and grounding cable installation positions on the S6850-56HF
switch
(1) Power module-side installation position for the mounting bracket
(2) Primary grounding point
(3) Auxiliary grounding point
(4) Port-side installation position for the mounting bracket
1 2 34

2-13
Figure2-19 Mounting brackets and grounding cable installation positions on the S6850-2C
switch
(1) Power module-side installation position for the mounting bracket
(2) Primary grounding point
(3) Auxiliary grounding point
(4) Port-side installation position for the mounting bracket
Figure2-20 Mounting brackets and grounding cable installation positions on the S9850-4C
switch
(1) Auxiliary grounding point 2
(2) Power module-side installation position for the mounting bracket
(3) Primary grounding point
(4) Port-side installation position for the mounting bracket
(5) Auxiliary grounding point 1
1234
12 3
4
1
5

2-14
Figure2-21 Mounting brackets and grounding cable installation positions on the S9850-32H
switch
(1) Power module-side installation position for the mounting bracket
(2) Primary grounding point
(3) Auxiliary grounding point
(4) Port-side installation position for the mounting bracket
Attaching the mounting brackets and chassis rails to the
chassis
1. Place the wide flange of the mounting bracket against the chassis side panel. Align the
mounting bracket installation holes with the appropriate screw holes in the chassis. Use the
provided M4 screws to attach the mounting bracket to the chassis (recommended torque: 12
kgf-cm).
To install the mounting brackets at the port-side mounting position, see Figure2-22,
Figure2-23, Figure2-24, Figure2-28, Figure2-30, and Figure2-32.
Use four installation holes to secure the mounting brackets to the S6850-56HF, S6850-2C,
and S9850-4C switches. Use three installation holes to secure the mounting brackets to the
S9850-32H switch.
To install the mounting brackets at the power module-side mounting position, see
Figure2-25, Figure2-26, Figure2-27, Figure2-29, Figure2-31, and Figure2-33.
Use four installation holes to secure the mounting brackets to the switch.
2. Determine the installation position of the chassis rails based on the position of mounting
brackets and the distance between the front and rear rack posts.
Table2-4 Chassis rail installation position
Switch model Mounting bracket
position Distance between the front and rear rack posts
Chassis rail
installation
position
S6850-56HF
(long slide rails)
Port-side mounting
position, as shown in
Figure2-22
692 to 788 mm (27.24 to 31.02 in) Position a
692 to 853 mm (27.24 to 33.58 in) Position b
Power module-side
mounting position, as
shown in Figure2-25
692 to 788 mm (27.24 to 31.02 in) Position c
692 to 853 mm (27.24 to 33.58 in) Position d
1234

2-15
Switch model Mounting bracket
position Distance between the front and rear rack posts
Chassis rail
installation
position
S6850-56HF
(super-short
slide rails,
chassis rails not
reaching out of
the chassis)
Port-side mounting
position, as shown in
Figure2-23
401 to 500 mm (15.79 to 19.69 in) Position a
457 to 565 mm (17.99 to 22.24 in) Position b
Power module-side
mounting position, as
shown in Figure2-26
401 to 500 mm (15.79 to 19.69 in) Position c
457 to 565 mm (17.99 to 22.24 in) Position d
S6850-56HF
(super-short
slide rails,
chassis rails
reaching out of
the chassis)
Port-side mounting
position, as shown in
Figure2-24
499 to 627 mm (19.65 to 24.69 in) Position a
564 to 692 mm (22.20 to 27.24 in) Position b
Power module-side
mounting position, as
shown in Figure2-27
499 to 627 mm (19.65 to 24.69 in) Position c
564 to 692 mm (22.20 to 27.24 in) Position d
S6850-2C
Port-side mounting
position, as shown in
Figure2-28
519 to 638 mm (20.43 to 25.12 in) Position a
524 to 703 mm (20.63 to 27.68 in) Position b
589 to 768 mm (23.19 to 30.24 in) Position c
654 to 833 mm (25.75 to 32.80 in) Position d
Power module-side
mounting position, as
shown in Figure2-29
589 to 768 mm (23.19 to 30.24 in) Position e
524 to 703 mm (20.63 to 27.68 in) Position f
520 to 638 mm (20.47 to 25.12 in) Position g
S9850-4C
Port-side mounting
position, as shown in
Figure2-30
675 to 923 mm (26.57 to 36.34 in) Position a
611 to 858 mm (24.06 to 33.78 in) Position b
546 to 793 mm (21.50 to 31.22 in) Position c
518 to 728 mm (20.39 to 28.66 in) Position d
Power module-side
mounting position, as
shown in Figure2-31
518 to 728 mm (20.39 to 28.66 in) Position e
546 to 793 mm (21.50 to 31.22 in) Position f
611 to 858 mm (24.06 to 33.78 in) Position g
S9850-32H
(long slide rails)
Port-side mounting
position, as shown
Figure2-32
621 to 788 mm (24.45 to 31.02 in) Position a
621 to 853 mm (24.45 to 33.58 in) Position b
Power module-side
mounting position, as
shown in Figure2-33
621 to 853 mm (24.45 to 33.58 in) Position c
621 to 788 mm (24.45 to 31.02 in) Position d
S9850-32H
(short slide rails)
Port-side mounting
position, as shown in
Figure2-32
401 to 588 mm (15.79 to 23.15 in) Position a
454 to 633 mm (17.87 to 24.92 in) Position b
Power module-side
mounting position, as
shown in Figure2-33
454 to 633 mm (17.87 to 24.92 in) Position c
401 to 568 mm (15.79 to 22.36 in) Position d
3. Place the chassis rail against the chassis side panel. Align the chassis rail installation holes with
the screw holes. Use the provided M4 screws to attach the chassis rail to the chassis
(recommended torque: 12 kgf-cm). See Figure2-22 to Figure2-31.
You can use super-short slide rails and long chassis rails to rack-mount the S6850-56HF switch.
Based on the rack depth, install the long chassis rails with the chassis rails not reaching out of

2-16
the chassis, as shown in Figure2-23 and Figure2-26 or with the chassis rails reaching out of the
chassis, as shown in Figure2-24 and Figure2-27.
Figure2-22 Attaching the mounting brackets and chassis rails to the S6850-56HF switch
(port-side mounting position for the mounting brackets, long slide rails)
Figure2-23 Attaching the mounting brackets and chassis rails to the S6850-56HF switch
(port-side mounting position for the mounting brackets, super-short slide rails, chassis rails
not reaching out of the chassis)
Figure2-24 Attaching the mounting brackets and chassis rails to the S6850-56HF switch
(port-side mounting position for the mounting brackets, super-short slide rails, chassis rails
reaching out of the chassis)
ab
ab
ab

2-17
Figure2-25 Attaching the mounting brackets and chassis rails to the S6850-56HF switch
(power module-side mounting position for the mounting brackets, long slide rails)
Figure2-26 Attaching the mounting brackets and chassis rails to the S6850-56HF switch
(power module-side mounting position for the mounting brackets, super-short slide rails,
chassis rails not reaching out of the chassis)
Figure2-27 Attaching the mounting brackets and chassis rails to the S6850-56HF switch
(power module-side mounting position for the mounting brackets, super-short slide rails,
chassis rails reaching out of the chassis)
cd
cd
cd

2-18
Figure2-28 Attaching the mounting brackets and chassis rails to the S6850-2C switch
(port-side mounting position for the mounting brackets)
Figure2-29 Attaching the mounting brackets and chassis rails to the S6850-2C switch (power
module-side mounting position for the mounting brackets)
Figure2-30 Attaching the mounting brackets and chassis rails to the S9850-4C switch
(port-side mounting position for the mounting brackets)
bcd
b
a
fg
e
abcd