Cisco Switch Catalyst 3850

About the Cisco Catalyst 3850 Series

The Cisco Catalyst 3850 is a stackable, fixed-configuration access switch family that
brought two things together in one chassis: multi-gigabit copper access and 10-Gigabit SFP+
uplinks. It was the first Catalyst access platform in which the wireless controller is
built into the switch itself, so an access layer of 3850s can terminate corporate Wi-Fi
locally instead of tunnelling every access point back to a dedicated controller appliance.

The range covers roughly 12-, 24- and 48-port copper models along with all-SFP variants,
and the platforms are joined by StackWise-480 — a stacking fabric that turns up to
eight switches into a single logical unit with one management address — and by
StackPower, which lets power supplies in the stack be pooled so one switch can feed
another if a PSU fails.

The series carries three software tiers, and the tier is written into the end of the part
number. It determines what the switch can actually do, so it is the first thing to check
before price:

• L — LAN Base. Layer 2 switching with a basic feature set. No wireless controller
  function and no advanced routing. On this tier, StackPower needs an additional cable to
  make full use of the shared-power feature.


• S — IP Base. Adds Layer 3 static and dynamic routing, and enables the built-in
  wireless controller for a small number of access points.


• E — IP Services. The full software set: advanced routing protocols, deeper QoS,
  and scale for a larger wireless deployment.

Two network modules in this category — C3850-NM-2-10G and
C3850-NM-8-10G — replace the fixed uplink module and are the usual way to lift
a 3850 to higher uplink bandwidth without changing the access ports.

How to Choose a Cisco Catalyst 3850

1. Decode the part number first

Every model reads WS-C3850-<ports><type>-<software>:
12S is 12 SFP ports, 12XS is 12 SFP/SFP+ ports at 1G/10G,
24P or 48P is 24 or 48 copper ports with PoE+, 48F is
the 48-port PoE+ model supplied with a 1100 W power supply, 24XU is the
multi-gigabit UPoE variant, and 12X48U is the mixed model that combines a
high-density copper tier with multi-gigabit ports. The trailing -L,
-S or -E is the software tier described above.

2. Pick the software tier by what the switch must do

This is where the money is, and where projects most often overspend:

• LAN Base (L) — pure Layer 2 access. Fine for a wiring closet terminating
  endpoints to a core that does the routing.


• IP Base (S) — the switch needs to route between VLANs at the access layer, or
  you want on-board wireless control for a handful of access points.


• IP Services (E) — full routing protocol support, or a wireless deployment large
  enough to need the higher controller scale.

3. Copper, fibre or multi-gigabit?

• All-SFP (12S, 12XS) — for a distribution or aggregation position where the
  downlinks are fibre rather than copper patch cords. The 12XS model carries SFP/SFP+
  ports at both 1G and 10G.


• Standard copper PoE+ (24P, 48P, 48F) — classic access-closet role: phones,
  cameras and 802.11ac access points on Cat 5e/Cat 6. The 48F variant ships with a
  1100 W power supply for sites with a heavy PoE load.


• Multi-gigabit UPoE (24XU, 12X48U) — where endpoints need more than 1 Gbps over
  existing copper, or where a single port must deliver up to 60 W. This is the variant
  for wave-2 access points, high-end video endpoints and dense IoT closets.

4. Stacking and uplinks

All models in the family stack through StackWise-480, with the fixed uplink module
field-replaceable by the 2-port or 8-port 10G network modules listed below. If you intend to
run a stack on the pooling feature rather than cable-by-cable power redundancy, confirm the
StackPower cabling requirement for the software tier you have chosen — on LAN Base an
additional cable is needed before StackPower is fully functional.

Cisco Catalyst 3850 Model Comparison

Prices are our current selling prices in US dollars, excluding shipping. Click a
model number for the full specification table and availability.

Uplink network modules

The uplink module in a 3850 is field-replaceable, so an existing switch can be lifted to
higher uplink bandwidth without changing its access ports:

Frequently Asked Questions

What do the L, S and E suffixes mean on a Catalyst 3850?

They are the software tiers. L is LAN Base (Layer 2 access, no wireless controller
function), S is IP Base (Layer 3 routing plus the built-in wireless controller at small
scale), and E is IP Services (the full routing and wireless feature set). The tier is
fixed by the part number and is not something that can be switched on later by configuration
alone.

What is the difference between the 12S and the 12XS models?

Both are 12-port SFP platforms, but the 12XS carries SFP/SFP+ ports that run at
either 1 Gbps or 10 Gbps, while the 12S is 1 Gbps SFP only. Choose the 12XS where the
uplink or downlink needs 10G.

Does the Catalyst 3850 have a built-in wireless controller?

Yes — the wireless controller function is integrated into the switch on the IP Base and IP
Services tiers. That is the main reason the 3850 was widely deployed in access layers: access
points can terminate locally instead of tunnelling to a separate controller. LAN Base models
do not provide this function.

What is StackPower and do I need an extra cable?

StackPower pools the power supplies across a stack, so a switch whose PSU fails can draw
power from its neighbours instead of dropping its powered devices. On the LAN Base
models an additional StackPower cable is required before the feature is fully functional —
this is a cabling requirement, not a licence one.

Can I add 10G uplinks to a 3850 I already own?

Yes. The uplink module is field-replaceable and both C3850-NM-2-10G (2 x 10G) and
C3850-NM-8-10G (8 x 10G) fit the platform, so uplink capacity can be raised without
replacing the switch.

Which model should I choose for a 48-port PoE closet?

If the switch only needs to switch at Layer 2, take a -L model. If it must route
between VLANs or run the on-board wireless controller, step up to the 48F-S — the same
48-port PoE+ layout, supplied with a 1100 W power supply for a heavier powered-device load.

Do you supply the stacking cables and power supplies separately?

Yes. Give us the model and the stack you are building and we will quote the StackWise and
StackPower cables, power supplies and transceivers alongside the switches.