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Joined: Sat Aug 27, 2022 8:46 pm

RB951G-2HnD & 1G interface speed

Sat Aug 27, 2022 9:15 pm

I'm using RB951G-2HnD (running RouterOS 6.49.6) behind a ISP supplied router (a Pace Plc model 5268AC). Both routers support 1G, auto negotiation is set on both sides. Both are set to advertise 1000BaseT/Full-duplex (and lower).

The RB951G-2HnD will only connect at 100Mbps (and claims only 100M is advertised on both sides, which isn't true).

[admin@host] > interface ethernet monitor 0
name: ether1-gateway
status: link-ok
auto-negotiation: done
rate: 100Mbps
full-duplex: yes
tx-flow-control: no
rx-flow-control: no
advertising: 10M-half,10M-full,100M-half,100M-full
link-partner-advertising: 10M-half,10M-full,100M-half,100M-full

The RB951G-2HnD clearly supports 1G, as seen by a PC connected.

admin@host] > interface ethernet monitor 1
name: ether2-master-local
status: link-ok
auto-negotiation: done
rate: 1Gbps
full-duplex: yes
tx-flow-control: no
rx-flow-control: no
advertising: 10M-half,10M-full,100M-half,100M-full,1000M-half,1000M-full
link-partner-advertising: 10M-half,10M-full,100M-half,100M-full,1000M-half,1000M-full

If I turn off auto negotiation and try to force 1000BaseT/Full-duplex on both sides, I have no connection.

If I disconnect the Mikrotik, and using the same patch cable & port connect a PC (with auto negotiation set on both sides), I connect at 1G.

I've read other posts that are similar, and am wondering if there is a solution now available?
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Joined: Thu Mar 03, 2016 10:23 pm

Re: RB951G-2HnD & 1G interface speed

Sun Aug 28, 2022 9:52 am

1Gbps connection uses all 4 pairs in UTP cable while 100Mbos onky uses 2 pairs. Inability to negotiate 1Gbps can indicate that one of those extra pairs is faulty - either cable is faulty or cotacts in RJ45 port are damaged. Since RB951G worjs @1Gbps when connected to another device (did you use same port?) this might indicate problem with ISP router's port or cable connecting it. RB951G has "cable check" functionality, so you may want to run it to see if anything suspicious pops up.

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