u/fagghujjakob

RB5009UG+S+ POE in on eth1 does not work on some POE switches

Router: RB5009UG+S+, RouterOS 7.23.3, connected on ether1, DC adapter

physically disconnected for all tests.

works - Cisco WS-C2960S (802.3at):

  Interface Admin  Oper  Power  Device    Class Max
  Gi1/0/1   auto   on    15.4   Ieee PD   4     30.0

Detected, classified class 4, powered, boots normally.

Fails - Cisco WS-C3850-12X48U (UPOE), IOS-XE 16.12.11:

  Interface: Gi2/0/26
  Inline Power Mode: auto
  Operational status: off
  Device Detected: no
  IEEE Class: n/a
  Absent Counter: 0
  Over Current Counter: 0
  Short Current Counter: 0
  Invalid Signature Counter: 0
  Power Denied Counter: 0

No ILPOWER log entry for this port, ever. Not a rejection - the switch

behaves as if nothing is connected.

Switch and cable are fine:

- Other PoE devices (incl. a TP-Link Omada AP) power on this exact port

with this exact cable

- Three class-4 PDs powered on the same module right now

- 493W of 600W free

- 10cm patch cable, switch straight to router

- Link comes up at 1Gbps, zero CRC errors

Tried on the Cisco side: power inline auto, static max 30000, 2-event,

shut/no shut, multiple ports including mGig.

Interesting detail: on RouterOS 7.22 it wouldn't power from the 2960-S

either. 7.23.3 fixed that, but the 3850 still doesn't see it at all. So

PoE-in behaviour does seem to be firmware-influenced on this board.

Anyone running an RB5009 off a UPOE or 802.3bt switch successfully? Trying

to work out whether this is my unit or the model.

My goal is to power the mikrotik form the switch like i used to do with my 2960 but on the 3850.

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u/fagghujjakob — 5 days ago