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second ethernet port on R720 not supporting NAS

peter_w_9h7tcet
Contributor II
Hi there.  Have a single ethernet line going to an outbuilding where I have an R720.  As this is the closest I have to "offsite" this is where I want to put my critical data backup NAS.  However, when plugged into the spare ethernet port in the R720, the NAS is not discoverable on my network. The PoE switch powering the R720 has plenty of power budget so this isn't the issue.

Just wondering if I need to change a setting that I am unaware of in my ZD1200 to enable a wired client on my R720.  

Many thanks.
18 REPLIES 18

DarrelRhodes
Valued Contributor
HI Peter,

Can you confirm that your R720 is being powered with 802.3at PoE power (upto 30w)?

If your switch is only sending 802.3af (15w) power, then the R720's second ethernet port will be disabled.

It should be easy to diagnose on the AP itself as the port LEDs won't be lit once you've connected your NAS.

If you have checked the above and your AP is getting enough power, then it might be a MDI/MDIX issue. I experienced this recently with an iMac plugging directly into an AP's second port.  It may be possible to configure this on your NAS or you may need to use a crossover Ethernet cable.

I hope that helps,
Darrel.

peter_w_9h7tcet
Contributor II
I have an ICX 7150 12 port switches - power budget 128W I think.  Each powering just 3 R720s, so I should have the power budget. 

I was wondering if it might be the length of the cable run which is dissipating the power?

If there's no obvious solution I may just put the critical data backup NAS somewhere in the house instead.


Hi Peter,

Great to hear you have the ICX7150 too.  However just because your switch has plenty of power budget (124W) - it doesn't guarantee the port is automatically providing the correct PoE power.  This will depend on the firmware version and whether you're running LLDP, etc.

The ICX switch will provide 30 watts 802.3at power with no issue for upto 100 metres on CAT5e.

You should be able to connect as you want but it looks like you might need a tweak to the config on the switch or your NAS.

Thanks,
Darrel.

syamantakomer
Moderator
Moderator
Hi Peter,

Just to add on what Darrel suggested, try SSH into the AP and check if AP is negotiating to 802.3at power.

get power-mode

if output shows that it is negotiating on 'af' then force the AP to get 'at' power using below command (assuming that your switch supports 802.3at).

set power-mode at

Image_ images_messages_5f91c452135b77e247a226fb_f9aef3aa1cc22292ab4da0fe3cf2a8e3_RackMultipart20200703106571y8a-25589fa1-1dd7-40d1-951c-461a131db885-178991341.png1593792245

Above is the chart from data sheet, which shows Power vs Operation characteristics of R720.

Also run below command to check eth port status, after connecting a device on 2nd port of R720.

get eth

Regards,
Syamantak Omer
Regards,
Syamantak Omer
Official Rep | Staff TSE | CWNA | CCNA | RASZA | RICXI
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