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M4300 switch: port is down after reboot
Hello community. I'm facing the following issue: I have 3x M4300 switches in a circle. After rebooting (reload) one of the switches, some of those ports connecting to the other 2x switches are do...
Hallo Johannes,
A little bit thin insights to provide an answer and discuss in the community.
In case there are 10G/1G SFP+ modules plugged, it's extremely likely these try to establish a 10G link - what might be not reliable when connecting to a DWDM port operating only on 1000M, since there is (different from copper Ethernet) no link negotiation. Suspect more a "random" effect of the "down" and "up".
Strongly recommend to use the appropriate SFP+ module (a pure SFP 1000BASE-FX for this fiber link) , and not to depend on some "auto"magic.
I'd suggest to get in contact with the Netgear ProAVDesign team (with LaurentMa at the helm), refer to this thread please, and chime back on the findings. This team is much nearer to the engineering than the community moderators or other "old crows" like me here.
Grüsse aus der Schweiz,
-Kurt.
One more thing to note:
I was using the "speed 1000 full-duplex" configuration command on several ports. While this config stayed the same on normal ports, it turned into a "no auto-negotiate" on port-channel "lag" ports. I've no idea, why...?!?
The "why" is defined in the IEEE 802.3 standards, Auto Negotiation is specified along with clause 28 when wally brain is right. While classic 10Mb/s Ethernet did not had AN, it became an option in 100 Mb/s Fast Ethernet. This completely changed since 1000Mb/s GbE: Auto Negotiation is mandatory for link speeds of 1 Gb/s and 10 Gb/s, later 2.5 Gb/s and 5 Gb/s was added similar.
"speed 1000 full-duplex" is often seen on networks configured by older crows - however, this is wrong in any aspect, while it's often accepted - it must be auto.
Regards,
-Kurt.
I rejoiced too soon. Unfortunately it's not working on the LAG channels after all. 😞 It works on the single ports, while on the channels the config is discarded after a reboot. What a pity.
Concerning the "it must be auto": setting the speed to 1000 on this Netgear switches, you MUST set either "full-duplex" or "half-duplex". The auto keyword is not available at this point. Any ideas?
Lieber Johannes,
While accepted in the CLI, already "speed 1000" - is wrong from the IEEE standardisation view on a copper port. Auto negotiation does not include the flow control only, it spans also to the speed. So please use "speed auto" instead if you have link speeds of 1000M and up on twisted pair copper connections.
Yes, this can be confusing as "speed [10] | [100] [half-duplex] | [full-duplex]" makes sense as this is in the admin hands (permitting the switch does support these low speeds) on twisted pair Ethernet ports.
Same non-issue on Cisco, HPE, Huawei, Juniper, ... switches supporting CLIs.
Back to the original question of "it's not working". Almost everything I wrote above is specific to copper (twisted pair) Ethernet. Somehow we lost the track a little bit.
In some early screenshots, there is an active 1000SX connection on a lower numbered port, where it apparently works there is also and you wrote about only having 1000M modules in place. Similar, the one in question does also show 1000SX media.
Again IEEE ... there is no auto negotiation on fiber links, never. The link speed is defined by the physical (fiber) module.
To make the reader's confusion complete:
At some point you talk of a LAG, and some ring layout!
A LAG can exist on two or more parallel physical links between the same devices.
A ring layout does require some STP (better RSTP for quicker re-config) which should be useful for your intended primary network usage. Keep in mind that on a ring not all connections can and will remain concurrently active - of course, STP or RSTP will temporarily disable one connection or a LAG to avoid a loop condition on your network.
Along with more details on the SFP modules, fiber connections, please also show us some simple sketch of your intended network layout, including LAG designations, RSTP/STP settings, .... Mark which physical connection (port and/or LAG) will go down.
Further on, I would like to promote using Netgear Engage, a free, local, non-cloud management application for the 4250, 4300, 4350, ... switches. Easy to get a layout from your physical network, easy access without bothering about the device CLI, simplified backup, config changes, firmware updates, .... or to exchange device configs, logs, and more with the Netgear Support, ...
Grüsse
-Kurt.
PS. Das Original-Angebot von ProAV Design Support Service besteht nach wie vor, und ist auch für Deine Switch-Modelle gültig. Die Kollegen helfen gerne aus, aber auf Grund des 24*7 Follow the Sun Dienstes vielleicht einfacher in Englisch. Und füge einen Link zu dieser Diskussion Deiner Anfrage hinzu bitte.
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