CRS106-1C-5S

The CRS106-1C-5S is a small switch built around fibre: five 1 Gbit SFP cages and one combo port that can be copper or fibre. It belongs where several fibre runs come together and there is no rack: a meter cupboard in a small commercial building, a plant room, a termination box.

The catalogue files it under switches, with the default configuration switch. That has consequences for the roles you are offered; see below.

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.

The ports

• combo1: one 1 Gbit combo port. A combo port has a copper socket and an SFP cage that exclude each other: you use one of the two. In practice this is your management port or your uplink.
• sfp2 through sfp6: five 1 Gbit SFP cages. This is what the device is for.

There is no PoE-out: the catalogue records no feeding port on this model, so the PoE-out per port field never appears. Anything that wants power over the cable needs an injector here.

The catalogue also records no WAN port, which is right for a switch: in the Switch role nothing is routed and there is no internet side. Which port becomes the trunk is chosen in the VLAN step; by default the role makes the last port a trunk and the rest access ports. See VLANs and Bridge and ports.

What is inside

From the catalogue: MIPSBE and 128 MB of memory. That is above the line where the configurator warns about tight memory, so you will not see that note here. The licence level and the switch chip are not recorded for this model, so this page does not quote them.

hw_vlan is empty, so the warning that bridge VLAN filtering turns hardware offload off does not apply here. 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: bringing a handful of fibre runs together at one point, with VLANs and a management address, in a cabinet with little room.

Where it runs out:

• One copper socket. And even then: combo1 is copper or fibre, not both at once.
• 1 Gbit. No 10 Gbit cages; if you want those, look at the CRS305 or the CRS309.
• Layer 2. In the Switch role nothing is routed; routing between VLANs happens on your router.
• Unverified port names. Check them before you paste.

Which roles fit

Because the catalogue knows this model as a switch, the roles that route are greyed out with the message "This is a switch": Home router, Office router with VLANs, VPN gateway, Router + CAPsMAN and Hotspot. The roles that need a radio are greyed out with "No wifi radio", and LTE / 5G router with "No LTE modem".

What is left:

• Switch: the role for this device. Every port in one bridge with RSTP, a VLAN table through /interface bridge vlan, 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: still technically offered, but that role writes routed interfaces without a bridge. That is not what this device is for.

The quickest route to a working configuration

1. Run /interface print on the device and write the port names down.
2. Pick One device and search for CRS106.
3. Pick the Switch role and walk through the wizard.
4. Watch two things: which port becomes the trunk, and which VLAN is your management VLAN.
5. Fill in the management address and the gateway. That address will be the only way to reach the switch.
6. Set an admin password, reset the device and paste the script. See Using the script.

If this switch sits between a router and a few access points, Multiple devices is faster: you draw the cables on the network board and the cabling decides the trunks.

What trips people up

• Using the combo port twice. Copper and fibre on combo1 exclude each other.
• Empty SFP cages. Without a matching module or DAC there is no link; see SFP port does not link.
• Locking yourself out. After pasting, the switch is only reachable on the management address in the management VLAN; see Switch unreachable.
• The management VLAN untagged on an ordinary port. Send it tagged towards your router.
• Forgetting the trunk on the other side. A VLAN that exists on only one end does not work; see VLAN checks.