Manual

CRS320-8P-8B-4S+RM

Sixteen 2.5 Gbit ports with PoE and four 10 Gbit cages, in a rack unit.

The CRS320-8P-8B-4S+RM is a rack switch with sixteen 2.5 Gbit copper ports and four 10 Gbit SFP+ cages. The 2.5 Gbit is the interesting part: it is the speed modern access points ask for, and it runs over cabling that is already there. That makes this the switch for a floor or a building full of access points, cameras and desks.

The catalogue files it under switches with the default configuration switch.

The port layout of this model is not verified in our catalogue. The tool therefore shows the "port layout not verified" note, and the script opens with a line saying the same. Run /interface print on the device and compare the names before you paste. That matters extra here; see the next paragraph.

The ports

  • ether1 through ether16: sixteen 2.5 Gbit copper ports. Our catalogue records PoE-out on all sixteen.
  • sfp-sfpplus1 through sfp-sfpplus4: four 10 Gbit SFP+ cages. The obvious place for your uplink or for an LACP bundle; see Bonding and LACP.

Note: the product code contains 8P-8B, which suggests two groups of eight, while our catalogue entry puts PoE-out on all sixteen ports and marks the port layout as not verified. The tool therefore offers you sixteen ports in the PoE list. Check on the device itself which ports actually feed, with /interface ethernet poe print, before you rely on it.

Because the catalogue records feeding ports, the PoE-out per port field appears, with auto-on, forced-on or off per port. About the power budget the tool knows nothing: not per port, not in total, and not what your supply delivers. Switching sixteen ports on does not mean sixteen devices come up. See PoE-out per port and Cables and PoE in practice.

The catalogue records no WAN port, which is right for a switch. The Switch role makes the last port a trunk by default; here that is sfp-sfpplus4, which usually works out well. See VLANs.

What is inside

From the catalogue: ARM 32bit, 256 MB of memory, licence level 5 and the 98DX226S switch chip. With 256 MB the small-board warning does not appear here.

hw_vlan is empty, so bridge VLAN filtering is the route we take on this model and the note about losing hardware offload stays away. Leave the Hardware offloading (switch chip) toggle under Ports on.

No radios and no modem, so no Wi-Fi package and no Wi-Fi generation in the catalogue entry.

What it is good at, and where it runs out

Good at: powering a lot of access points and cameras at 2.5 Gbit, with four fast cages to the rest of the network. For a building with Wi-Fi everywhere this is the obvious distribution switch; see A guest network at every site and Recipe: Wi-Fi in a warehouse.

Where it runs out:

  • Unverified port layout. Check names and PoE ports on the device.
  • The power budget. Outside the tool's reach.
  • Layer 2. In the Switch role nothing is routed.
  • No Wi-Fi and no modem. All Wi-Fi roles are greyed out with "No wifi radio", LTE / 5G router with "No LTE modem".

Which roles fit

Because the catalogue knows this model as a switch, the roles that route are greyed out with "This is a switch": Home router, Office router with VLANs, VPN gateway, Router + CAPsMAN and Hotspot.

What is left:

  • Switch: the role for this device. Every port in one bridge with RSTP, a VLAN table, a static management address on the management VLAN, no DHCP server, no NAT and no routing.
  • Harden only (baseline): for a switch that is already running.
  • Core router: technically offered, but not what this device is for.

The quickest route to a working configuration

  1. Run /interface print and /interface ethernet poe print on the device and write down what you see.
  2. Pick One device and search for CRS320.
  3. Pick the Switch role and walk through the wizard.
  4. Watch which port becomes the trunk and which VLAN is your management VLAN.
  5. Go to advanced, the Ports section, and switch PoE-out on for the ports you really use, and only where the device says they can feed.
  6. Set an admin password, reset the device and paste the script. See Using the script.

With many access points on it, Multiple devices is handier: the cabling on the network board then decides the trunks and the checks tell you whether the management VLAN reaches everything.

What trips people up

  • Assuming all sixteen ports feed. The catalogue says they do, and it is not verified for this model. Look at the device.
  • Switching PoE on without doing the sums. Add up what you connect.
  • forced-on when in doubt. Voltage without detection can damage equipment that expects no PoE.
  • Expecting 2.5 Gbit from old cabling. If you do not reach the speed, look at the cable first; see Wired speed is lower than expected.
  • Locking yourself out. See Switch unreachable.

Want to try it right away? Open the configurator