IPT problems with VLANs on 3650 on IOS 16.6.4a

[rasmus.elmholt]

Hi

I have a strange problem with some IP Phones after I upgraded a 3650 switch to IOS version 16.6.4a.

I have 7 phones connected to port on the switch and after the upgrade the phones loses connectivity after a day or 2.

When the phones connect they get an IP in the Voice VLAN, but after some time they drop the connection to the PBX.

To me it seems like the phones move from the tagget voice vlan to the untagged data vlan on the switch but not completely.

Port config:

interface GigabitEthernet2/0/15
 description <User/voice port>
 switchport access vlan 548
 switchport mode access
 switchport voice vlan 549
 switchport port-security maximum 2
 switchport port-security aging time 10
 switchport port-security
 spanning-tree portfast
end

I can see the MAC of the phone on the data VLAN, but the IP is in the VOICE vlan scope, and it replies to a ping.

SW-1#show mac address-table | inc 0/15
 548    0008.5d92.2fd8    STATIC      Gi2/0/15 
 548    4439.c48d.332f    STATIC      Gi2/0/15 
SW-1#show ip arp | inc 0008.5d92.2fd
Internet  10.60.49.13             0   0008.5d92.2fda  ARPA   Vlan549
SW-1#ping 10.60.49.13
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.60.49.13, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
SW-1#show mac add
SW-1#show mac address-table | inc 0008.5d92.2fd8
 548    0008.5d92.2fd8    STATIC      Gi2/0/15 

This problem started a week after i upgraded the 3650 switch and we have had the setup for 2 years without problems before that.

Have anyone seen anything like this?

[Georg Pauwen]

Hello,

try to default the port (default interface GigabitEthernet2/0/15), and then reapply the entire configuration...

[rasmus.elmholt]

Have you experienced the same and solved it with reapplying the configuration or is it just a guess?

[rasmus.elmholt]

After some tshooting the phones wasn't configured to use a voice VLAN, and just sent all traffic untagged/native.
But they still have problems with losing IP connectivity.

[Leo Laohoo]

Try upgrading the firmware of the switch/stack. The version currently being used is a "rebuild".

[rasmus.elmholt]

What version would you recommend then? 16.6.4a is the suggested version and everything below 16.6.4 is hitting the PoE Bug?

[Leo Laohoo]

---

@rasmus.elmholt wrote:
16.6.4a is the suggested version

---

16.6.5 was released on December 2018.

[rasmus.elmholt]

Just updated to 16.6.5 yesterday. Same problem.
**bleep** this is some buggy code.

[Leo Laohoo]

When the phones "drop", they don't lose power, do they?

[rasmus.elmholt]

No they don't. And the computer behind the phone is working as well.
I can see the MAC address of the phone in the CAM table.
I cannot ping the phone or see it in the arp table.
Not even a monitor capture on the port showed me any traffic to or from the phone.
I have tried with both tagged and untagged phone traffic. But none of it worked.

I have just downgraded to 16.3.7 and It have now been stable for half a day.