Link advertisement doesn't seem to work correctly

shimi · Tue Jan 25, 2022 1:09 pm

Hello folks,

I have connected my Synology NAS to CRS326-24G-2S+ (running ROS 7.1.1) using 10gbe SFP+ module. The connection works normally but the log of the switch is flooded by warnings of too high temperature of the SFP+ module.

I wanted to find out if lowering a link speed could lead to better thermal management, so I set the link speed advertisement to 1, 2.5 and 5 gbps only. The auto negotiation is on. But the rate remains on 10gbps. What am I missing?

set [ find default-name=sfp-sfpplus2 ] advertise=1000M-full,2500M-full,5000M-full \
    name=sfpplus2-syno-10gbe

                               name: sfpplus2-syno-10gbe
                             status: link-ok
                   auto-negotiation: done
                               rate: 10Gbps
                        full-duplex: yes
                    tx-flow-control: no
                    rx-flow-control: no
                        advertising: 10M-half,10M-full,100M-half,100M-full,1000M-half,
                                     1000M-full,10000M-full,2500M-full,5000M-full
           link-partner-advertising: 100M-full,1000M-full,10000M-full,2500M-full,
                                     5000M-full
                 sfp-module-present: yes
                        sfp-rx-loss: no
                       sfp-tx-fault: no
                           sfp-type: SFP-or-SFP+
                 sfp-connector-type: RJ45
  sfp-link-length-copper-active-om4: 1m
                    sfp-vendor-name: MikroTik
             sfp-vendor-part-number: S+RJ10
                sfp-vendor-revision: 2.16
                  sfp-vendor-serial: AF94031____E
             sfp-manufacturing-date: 21-01-13
                    sfp-temperature: 84C
                 sfp-supply-voltage: 3.269V
                sfp-tx-bias-current: 0mA
                    eeprom-checksum: good

mkx · Tue Jan 25, 2022 1:58 pm

Try to restart the link, disconnecting UTP cable for a few seconds should do the trick ... AFAIK link speed re-negotiation only takes place when link is establishing.

shimi · Tue Jan 25, 2022 5:03 pm

Thanks @mkx for your suggestion.

Unfortunately, the problem remains unsolved. I have not only disconnected and reconnected the cable, I have also restarted the switch and the negotiated link speed remains 10 gbps.

Edit:
I have also tried to set auto-negotiation=no and speed=2.5Gbps and after re-establishing the connection the link speed remains at 10Gbps. BTW, there is no way to manually set the link speed to 5Gbps.

kiler129 · Wed Jan 26, 2022 2:44 am

Don't you maybe have two of these modules installed? 10GbE modules are nasty-hot regardless of the brand & model - it's just the limitation of the chips. MT even has a guidance about that: https://wiki.mikrotik.com/wiki/S%2BRJ10 ... l_guidance - you may need to add a fan in your switch if you want to use this module. Many passive switches with SFP specifically don't support RJ45 10Gb modules due to thermals.

shimi · Wed Jan 26, 2022 10:39 am

MT even has a guidance about that: https://wiki.mikrotik.com/wiki/S%2BRJ10 ... l_guidance

I read the article, that's why I installed just one module.

The problem could be that I am apparently using the older revision of the module, which presumably had problems with link speed advertisement (https://mikrotik.com/product/s_rj10).

I am going to add a fan to the switch...

Link advertisement doesn't seem to work correctly

Link advertisement doesn't seem to work correctly

Re: Link advertisement doesn't seem to work correctly

Re: Link advertisement doesn't seem to work correctly

Re: Link advertisement doesn't seem to work correctly

Re: Link advertisement doesn't seem to work correctly

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