Network not available for PC connected behind cisco 7800 after long idle

[iantra123]

Hello,

I experience this problem: Each morning most of our PC have to be disconnected and reconnected manually to  with the IPPhone or have to be restarted so that it can connect to the network.

Explanation : 

We have Cisco 7800 series (7821, 7841, 7861), and there are many PC (HP brand) that are connected in the PC port of the IPPhone. During the whole day, there is no disconnection of the PC. Then people leave the office, and the next morning when they come back the PC is disconnected. the LED on the network are blinking but there is no network.

PCs that are connected directly to the switches doesn't present this problem. Only the PC that are connected with the IPPhone presents this problem.

Is there any solution for this? How to overcome this issue?

Regards,

Antra

[Nithin Eluvathingal]

Please check EnergyWise setting on the phone. 

[Jonathan Schulenberg]

Does the access layer switch have 802.1x configured? An ISE/RADIUS issue could easily explain why traffic isn’t being permitted; rebooting or reconnecting the cable would trigger a new authentication.

[iantra123]

Hello,

Yes, 802.1x is activated on the Meraki switch. It is activated for the data vlan, not for the IPPhones.

EnergyWise disabled.

Regards

[pobcisco1]

Did you ever find a fix for this issue? We're having the same issue.

[punchy]

Same issue here.  We have a TAC case open currently and have made very little progress.  If anyone has found a solution, please share!

[chris-doro]

Same issue here in March 2025.

[chris-doro]

We've the same issue with some of our 7861 and maybe 7841 (not sure).
We already had this problem before we started to use 802.1x.
Just simple basic voice configuration with voice VLAN tagged and data VLAN untagged.
The clients are working for weeks (months) but suddenly the have no longer network connection.
Restarting the telephone and rebooting the client does NOT solve the issue.
But the MAC addresses of client and phone are still shown on switchboard in the correct VLANs.
The only way to repair it, to connect the client to switch without the phone.

[punchy]

We just recently resolved this issue.  It was a massive headache for us and took a long time to get resolved.  I'm not sure of the exact technical details, but for us it had to do with ARP traffic from the PC attached to the phone being reflected back from the switch.  Essentially, the phone was receiving an ARP packet with the MAC of the PC coming FROM the switch, which confused the phone and broke things.  Very long story short, Cisco TAC ultimately found this issue, which ended up being with the Aruba switches.  They developed a patch, which we tested, and has now been rolled into their latest switch firmware.  We recently completed the rollout and to my knowledge, we have not seen the issue since.  

[chris-doro]

But we use Cisco switches C9200 and C9300, and we also seen this issue on Cisco 2960. 
So it's the full Cisco stuff, Cisco phones, Cisco switches...
We can not replace them with Aruba switches.