For initial switch setup, assigning the switch IP address, and powering
on information, see the switch getting started guide on Cisco.com.
This chapter contains these topics:
This section includes the
basic installation caution and warning statements. Read this section before you
start the installation procedure. Translations of the warning statements appear
in the Regulatory Compliance and Safety Information guide on Cisco.com.
Before working on
equipment that is connected to power lines, remove jewelry (including rings,
necklaces, and watches). Metal objects will heat up when connected to power and
ground and can cause serious burns or weld the metal object to the terminals.
Do not stack the
chassis on any other equipment. If the chassis falls, it can cause severe
bodily injury and equipment damage. Statement 48
must be shielded when used in a central office environment. Statement 171
Do not work on the
system or connect or disconnect cables during periods of lightning activity.
installation instructions before connecting the system to the power source.
Class 1 laser
product. Statement 1008
This unit is
intended for installation in restricted access areas. A restricted access area
can be accessed only through the use of a special tool, lock and key, or other
means of security. Statement 1017
combination must be accessible at all times, because it serves as the main
disconnecting device. Statement 1019
conductors only. Statement 1025
This unit might
have more than one power supply connection. All connections must be removed to
de-energize the unit. Statement 1028
Only trained and
qualified personnel should be allowed to install, replace, or service
this equipment. Statement 1030
of this product should be handled according to all national laws and
regulations. Statement 1040
To prevent the
system from overheating, do not operate it in an area that exceeds the maximum
recommended ambient temperature of:
<113°F (45°C). Statement 1047
the equipment must comply with local and national electrical codes. Statement
To prevent airflow
restriction, allow clearance around the ventilation openings to be at least: 3
inches (7.6 cm). Statement 1076
architecture of this product is DC-isolated (DC-I).
When determining where to
install the switch, verify that these guidelines are met:
Clearance to the switch front
and rear panel meets these conditions:
Front-panel LEDs can be
Access to ports is sufficient
for unrestricted cabling.
AC power cord can reach from
the AC power outlet to the connector on the switch rear panel.
The SFP or SFP+ module
minimum bend radius and connector length is met. See the SFP or SFP+ module
documentation for more information.
Cabling is away from sources
of electrical noise, such as radios, power lines, and fluorescent lighting
fixtures. Make sure that the cabling is safely away from other devices that
might damage the cables.
For switches with the
optional 1100-W power-supply module (PWR-C1-1100WAC=), first rack-mount the
switch before installing the power-supply module.
- Make sure power-supply
modules and fan modules are securely inserted in the chassis before moving the
- When connecting or
disconnecting the power cord on a switch that is installed above or below a
1100-W power supply-equipped switch, you might need to remove the module from
the switch to access the power cord.
Airflow around the switch and
through the vents is unrestricted.
- For copper connections on
Ethernet ports, cable lengths from the switch to connected devices can be up to
328 feet (100 meters).
Temperature around the unit
does not exceed 113°F (45°C). If the switch is installed in a closed or
multirack assembly, the temperature around it might be greater than normal room
Humidity around the switch
does not exceed 95 percent.
Altitude at the installation
site is not greater than 10,000 feet.
Cooling mechanisms, such as
fans and blowers in the switch, can draw dust and other particles causing
contaminant buildup inside the chassis, which can result in system malfunction.
You must install this equipment in an environment as free from dust and foreign
conductive material (such as metal flakes from construction activities) as is
The switch getting started
guide describes the box contents. If any item is missing or damaged, contact
your Cisco representative or reseller for support.
Tools and Equipment
Obtain these necessary tools:
Before you install
the switch in a rack, or on a table or shelf, you should power on the switch
and verify that the switch passes POST. See the “Running Express Setup” section
in the getting started guide for the steps required to connect a PC to the
switch and to run Express Setup.
Powering Off the
After a successful POST,
disconnect the power cord from the switch. Install the switch in a rack, on a
table, or on a shelf as described in
Installing the Switch.
Planning a Switch
Catalyst 3850 switches
can share bandwidth by using data stacking.
The following switch
models do not support StackWise-480:
Switch Stacking and
Power Stacking Guidelines
Before connecting the
switches in a stack, keep in mind these stacking guidelines:
considerations for the following switch models:
If you set up a
stack with these switches, the stack can have a maximum of 8 switches only.
Each of the above switch models have 4 ASIC chips, and the maximum number of
ASIC chips per stack cannot exceed 32.
If you set up a
stack that contains the above switches and other Catalyst 3850 switches, ensure
that the maximum number of ASIC chips is 32.
WS-C3850-48XS switch models do not support power stacking.
Data Stack Cabling
This is an example of a
recommended configuration that uses the supplied 0.5-meter StackWise cable. In
this example, the switches are stacked in a vertical rack or on a table. This
configuration provides redundant connections. The configuration example uses
the supplied 0.5-meter StackWise cable. The example shows the full-ring
configuration that provides redundant connections.
Figure 1. Data Stacking the Switches in
a Rack or on a Table Using the 0.5-meter StackWise Cables
This example shows a
recommended configuration when the switches are mounted side-by-side. Use the
1-meter and the 3-meter StackWise cables to connect the switches. This
configuration provides redundant connections.
Figure 2. Data Stacking in a
Data Stack Bandwidth
and Partitioning Examples
This section provides
examples of data stack bandwidth and possible data stack partitioning. The
figure shows a data stack of switches that provides full bandwidth and
redundant StackWise cable connections.
Figure 3. Example of a Data Stack with
Full Bandwidth Connections
This figure shows an
example of a stack of switches with incomplete StackWise cabling connections.
This stack provides only half bandwidth and does not have redundant
Figure 4. Example of a Data Stack with
Half Bandwidth Connections
The figures below show
data stacks of switches with failover conditions. In this figure, the StackWise
cable is bad in link 2. Therefore, this stack provides only half bandwidth and
does not have redundant connections.
Figure 5. Example of a Data Stack with
a Failover Condition
In this figure, link
2 is bad. Therefore, this stack partitions into two stacks, and the top and
bottom switches become the active switch in the stack. If the bottom switch is
a member (not active or standby switch), it reloads.
Figure 6. Example of a Partitioned Data
Stack with a Failover Condition
Power-On Sequence for Switch Stacks
Consider these guidelines
before you power on the switches in a stack:
The sequence in which the
switches are first powered on might affect the switch that becomes the stack
There are two ways to elect
an active switch:
- If you want a particular
switch to become the active switch, configure it with the highest priority.
Among switches with same priority, the switch with the lowest MAC address
becomes the active switch.
If you want
a particular switch to become the active switch, power on that switch first.
This switch remains the active switch until a reelection is required. After 2
minutes, power on the other switches in the stack. If you have no preference as
to which switch becomes the active switch, power on all the switches in the
stack within 1 minute. These switches participate in the active switch
election. Switches powered on after 2 minutes do not participate in the
If changes are
made to the stack without powering down the switches, the following results can
If two operating partial ring
stacks are connected together using a stack cable, a stack merge can take
place. This situation reloads the whole stack (all switches in the stack).
- If some switches in the stack
are completely separated from the stack, a stack split can occur.
- A stack split can occur on a
full ring stack if:
- More than one running switch
is removed without powering down.
- More than one stack cable is
removed without powering down.
- A stack split can occur in a
partial ring stack if:
- A switch is removed without
- A stack cable is removed
without powering down.
- In a split stack, depending
on where the active and standby switches are located, either two stacks might
be formed (with the standby taking over as the new active switch in the newly
formed stack) or all the members in the newly formed stack might reload.
depend on how the switches are connected. You can remove two or more switches
from the stack without splitting the stack.
For conditions that can cause a stack reelection or to manually elect the active switch, see the stacking software configuration guide on Cisco.com at this URL: http://www.cisco.com/c/en/us/support/switches/catalyst-3850-series-switches/products-installation-and-configuration-guides-list.html.
You can configure a
StackPower stack for either power sharing or redundancy. In power-sharing mode,
the power of all the power supplies in the stack is aggregated and distributed
among the stack members.
In redundant mode,
when the total power budget of the stack is calculated, the wattage of the
largest power supply is not included. That power is held in reserve and used to
maintain power to switches and attached devices when one power supply fails.
Following the failure of a power supply, the StackPower mode becomes power
Power-sharing mode is the recommended configuration for Cisco Catalyst 3850 Series Switches .
For general concepts and management procedures for switch power stacks, see the Software Configuration Guide on Cisco.com.
Before connecting the
switches in a power stack, keep in mind these guidelines:
- A switch power stack can include a maximum of four switches in a ring topology and nine switches in a star topology.
- Size of the switch and any
optional power supply module. The 1100-W power-supply module is 1.5 inches
(3.81 cm) longer than the other modules, and with the attached cable retention
clip, it extends 3 inches (7.62 cm) from the switch chassis. Stacking switches
with the same power-supply modules together makes it easier to cable the
switches. For switch dimensions, see Appendix A, “Technical Specifications.”
- Length of cable. Depending on
the configurations that you have, you might need different-sized cables. If you
do not specify the length of the StackPower cable, the 0.3 meter cable is
supplied. If you need the 1.5 meter cable, you can order it from your Cisco
supplier. For cable part numbers, see
StackPower Cabling Configurations
provides examples of recommended configurations.
- For rack-mounted switch stacks that are members of a data stack and a StackPower stack, see Switch Stacking and Power Stacking Guidelines
describes the recommended cabling configurations for a StackPower stack. There
are two types of StackPower cables.
The cable in the
figure connects a switch to another switch in a power stack or with an XPS.
StackPower cables have color bands on the cable ends:
- The cable end with the green
band can connect only to a switch.
- The cable end with the yellow
band can connect to a switch or an XPS.
The cable is
available in two lengths.
Figure 7. StackPower Cable for Use with Cisco Catalyst 3850 Series Switches
This figure shows
a ring configuration using both of the supplied 0.3-meter StackPower cables and
one 1.5-meter cable. In the examples that follow, the switches are stacked in a
vertical rack or on a table.
Figure 8. StackPower Ring
shows nine switches connected in a star topology.
These figures show StackPower
stacks of switches with failover conditions.
In this figure, the
StackPower cable 2 is faulty. Therefore, this stack does not provide
Figure 9. Example of a StackPower Stack
with a Failover Condition
In this figure,
StackPower port B on the center switch has failed and this stack partitions
into two stacks. The top two switches share power, and the bottom switch is now
a separate stack.
Figure 10. Example of a Partitioned
StackPower Stack with a Failover Condition
Installation in racks other
than 19-inch racks requires a bracket kit not included with the switch.
Figure 11. Rack-Mounting
Brackets. This figure shows
the standard 19-inch brackets and other optional mounting brackets. You can
order the optional brackets from your Cisco sales representative.
To prevent bodily
injury when mounting or servicing this unit in a rack, you must take special
precautions to ensure that the system remains stable. The following guidelines
are provided to ensure your safety:
Extension rails and brackets
for four-point mounting, includes 19-inch brackets. (C3850-4PT-KIT=)
|Use four Phillips flat-head
screws to attach the long side of the bracket to each side of the switch for
the front- or rear-mounting positions.
Figure 12. Attaching Brackets for
19-inch Racks |
Figure 13. Attaching Brackets for
Catalyst WS-C3850-48XS Switches
Number-8 Phillips flat-head
Mounting the Switch
||Use the four
supplied Phillips machine screws to attach the brackets to the rack.
||Use the black
Phillips machine screw to attach the cable guide to the left or right bracket.
machine screw, black
number-10 Phillips machine screws
Installing the Switch on a Table or Shelf
||To install the switch on a
table or shelf, locate the adhesive strip with the rubber feet in the
||Attach the four rubber feet
to the four circular etches on the bottom of the chassis.
||Place the switch on the table
or shelf near an AC power source.
||When you complete the switch installation, see After Switch Installation
for information on switch configuration. |
After Switch Installation
Configure the switch by
running Express Setup to enter the initial switch configuration. See the switch
getting started guide on Cisco.com.
Use the CLI setup program to
enter the initial switch configuration.
Connect to the stack ports.
Connect to the front-panel
Connecting to the
Before You Begin
Before connecting the StackWise cables, review the Planning a Switch Data Stack. Always use a Cisco-approved StackWise cable to connect the switches.
||Remove the dust
covers from the StackWise cables and StackWise ports, and store them for future
cable to the StackWise port on the switch rear panel. Align the connector and
connect the StackWise cable to the StackWise port on the switch rear panel and
finger-tighten the screws (clockwise direction). Make sure the Cisco logo is on
the top side of the connector as shown in the figure.
|| Connect the
other end of the cable to the port on the other switch and finger-tighten the
screws. Avoid overtightening the screws.
Figure 14. Connecting the StackWise Cable in a StackWise Port|
||Removing and installing the StackWise cable can shorten its
useful life. Do not remove and insert the cable more often than is absolutely
necessary (installing and removing it up to 200 times is supported).
When you need to remove the StackWise cable from the connector, make sure to fully unscrew the correct screws. When the connectors are not being used, replace the dust covers.
Connecting to the
Before You Begin
Before connecting the StackPower cables, review Planning a Switch Data Stack. Always use a Cisco-approved StackWise cable to connect the switches. To prevent misconfiguration, the StackPower ports on the switch are keyed and have colored bands that match the keying and bands on the StackPower cable connectors.
||Remove the dust
covers from the StackPower cable connectors.
||Connect the end
of the cable with a green band to either StackPower port on the first switch.
Align the connector correctly, and insert it into a StackPower port on the
switch rear panel.
||Connect the end
of the cable with the yellow band to another switch (to configure StackPower
the captive screws to secure the StackPower cable connectors in place.
||Removing and installing the StackPower cable can shorten its
useful life. Do not remove and insert the cable more often than is absolutely
Installing a Network
Module in the Switch
See these sections for
information on network modules:
Removing SFP, SFP+ and QSFP+ Modules
See these sections for
information on SFP, SFP+ and QSFP+ modules:
to the Ethernet Ports
10/100/1000 Port Connections
The switch 10/100/1000 port
configuration changes to operate at the speed of the attached device. If the
attached ports do not support autonegotiation, you can manually set the speed
and duplex parameters. Connecting devices that do not autonegotiate or that
have the speed and duplex parameters manually set can reduce performance or
result in no linkage.
To maximize performance,
choose one of these methods for configuring the Ethernet ports:
careful when connecting a “snagless” Ethernet cable to port 1 on a 48-port
switch. The protective boot of the cable might inadvertently press the Mode
button, which could cause the switch to erase its startup configuration and
reboot. See this field notice for more information:
This issue does not
occur if you are using Cisco IOS XE Release 3E or later releases.
The autonegotiation and the
auto-MDIX features are enabled by default on the switch.
With autonegotiation, the
switch port configurations change to operate at the speed of the attached
device. If the attached device does not support autonegotiation, you can
manually set the switch interface speed and duplex parameters.
With auto-MDIX, the switch
detects the required cable type for copper Ethernet connections and configures
the interface accordingly.
If auto-MDIX is
disabled, use the guidelines in this table to select the correct cable.
1 100BASE-TX and 1000BASE-T traffic requires twisted four-pair, Category 5 or higher. 10BASE-T traffic can use Category 3 cable or higher.
Table 1 Recommended Ethernet Cables
(When Auto-MDIX is Disabled)
Switch to switch
Switch to hub
Switch to computer or server
Switch to router
Switch to IP phone
PoE+ and Cisco UPOE
The 10/100/1000 PoE+ and
Cisco UPOE ports have the same autonegotiation settings and cabling
requirements that are described in the
10/100/1000 Port Connections.
These ports can provide PoE, PoE+, or Cisco UPOE inline power.
PoE inline power
supports devices compliant with the IEEE 802.3af standard, as well as
prestandard Cisco IP Phones and Cisco Aironet Access Points. Each port can
deliver up to 15.4 W of PoE. PoE+ inline power supports devices compliant with
the IEEE 802.3at standard, by delivering up to 30 W of PoE+ power per port to
all switch ports.
See Power Supply Modules for the power supply modules required to support PoE, PoE+, and Cisco UPOE on 24- and 48-port switches.
present a shock hazard may exist on Power over Ethernet (PoE) circuits if
interconnections are made using uninsulated exposed metal contacts, conductors,
or terminals. Avoid using such interconnection methods, unless the exposed
metal parts are located within a restricted access location and users and
service people who are authorized within the restricted access location are
made aware of the hazard. A restricted access area can be accessed only through
the use of a special tool, lock and key or other means of security. Statement
Voice over IP
(VoIP) service and the emergency calling service do not function if power fails
or is disrupted. After power is restored, you might have to reset or
reconfigure equipment to regain access to VoIP and the emergency calling
service. In the USA, this emergency number is 911. You need to be aware of the
emergency number in your country. Statement 371
Category 5e and Category 6
cables can store high levels of static electricity. Always ground the cables to
a suitable and safe earth ground before connecting them to the switch or other
Noncompliant cabling or powered devices can cause a PoE port
fault. Use only standard-compliant cabling to connect Cisco prestandard IP
Phones and wireless access points, IEEE 802.3af, or 802.3at (PoE+)-compliant
devices. You must remove any cable or device that causes a PoE fault.
Where to Go Next
If the default configuration is satisfactory, the switch does not need further configuration. You can use any of these management options to change the default configuration:
- Start the Network Assistant application, which is described in the getting started guide. Through this GUI, you can configure and monitor a switch cluster or an individual switch.
- Use the CLI to configure the switch as a member of a cluster or as an individual switch from the console.
- Use the Cisco Prime Infrastructure application.