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Community Member

Image bugs

I recently started upgrading our small business line to image This includes an SG300-20 and five SG300-28P 's.  The first thing I noticed is that the switch applies port power well before the switch has finished booting and is forwarding frames. Image was perfect and waited to add power once the switch was operational on all ports. Definitely not the end of the world and possibly not a bug at all; our IP phones eventually time out and retry and the switch is then operational.

The second thing is that in layer 3 mode, setting a static IP on the managment VLAN address does correctly add 'no ip address dhcp'  to the config file, but NOT the IP address and subnet mask. This must be entered manually from the CLI. I did a copy run start and rebooted a switch, and was left locked out with no choice but to use the console to add the missing information. This happened on two separate 28P 's.

On the second switch that had the missing ip address in VLAN 1 (but did indeed have the  no ip address dhcp entry),  only the first bank of ports had PoE. Removing and restoring AC power brought PoE back to all ports. Out of all strange behaviors, this one worried me the most.

The third problem I noticed was that LLDP no longer gave our Mitel 5330 IP phones VLAN information. Despite rebooting to defaults, resets, etc... Rolled back to image and it suddenly worked again. I have since decided to use DHCP to provide that information to the phones, and turned off auto smartport as I don't like blinking Save all the time, and endless macros to scroll through in the config file. No matter what image you use, LLDP doesn't provide VLAN info on initial switch boot, after a power inline never / auto, and sometimes even after and port shutdown and power inline never/auto. The only way to get it for sure is to unplug and re-plug the phone. This was why I switched to DHCP for that task.

Dismissing these originally as upgrade config incompatibilities, I rebooted to factory defaults and reprogrammed manually. All these problems persisted. I'm currently running half equipment the new image and half  It seems currently image is the best image to use as it is stable and also does not have the MAC table port flooding bug that and below had. does have some nice new features, but I'm too scared to deploy it to switches over 10 miles away from the office.

Everyone's tags (2)

Re: Image bugs

Hello Brayton, I have spent a few minutes labbing the information provided. To summarize what you're saying;

1.) On the UI if you delete the DHCP interface for VLAN 1 or use the command string, the IP information / subnet mask does not display correctly. I have performed the following steps;

set system mode router (layer 3)

switche56e94# configure terminal

switche56e94(config)# interface vlan 1

switche56e94(config-if)#no ip address dhcp

switche56e94(config)#do show run int vlan 1

interface vlan 1

no ip address dhcp


switche56e94(config)#do show ip interface vlan 1 static disable no Valid

I have tested this both on the and the The IP address and subnet mask does not show on the show run interface vlan 1.  However, if you specifically assigned the VLAN interface the IP address, it does show.

On the GUI, the only IP interface that will show will be the static. At no point did I lose access to the switch however.

2.) I have not experienced any POE issues modifying IP address or VLAN information. A few things you can do to see what is going on.

show power inline fastethernet xx  - This will show if you have an absent counter or an invalid signature etc.  If you have an invalid signature the port would go to a shut down state and would require a power inline never/auto command or renegotiation of the port for the POE.

3.) The LLDP MED is no longer feeding VLAN information to your Mitel phone on the initial switch boot.

To prepare the switch I have performed the following;

configure terminal

no cdp run

no cdp appliance-tlv enable

vlan database

vlan 100


voice vlan state disabled

no lldp med network-policy voice auto

lldp med network-policy 1 voice vlan 100 vlan-type tagged up 6 dscp 46

interface fastethernet 2

lldp optional-tlv port-desc sys-name sys-desc sys-cap 802.3-mac-phy 803.3-lag 802.3-max-frame-size

lldp med network-policy add 1

lldp management-address automatic

switchport trunk allowed vlan add 100

do wr mem

do show mac-address table

vlan       mac address     port     type

1        64:9e:f3:77:5e:5d   fa2    dynamic

100    64:9e:f3:77:5e:5d   fa2    dynamic

I have connected a SPA509G telephone running 7.5.1 firmware. The phone correctly picked up the voice vlan 100. After rebooting the switch, it continued to work as expected.  I  did not have to power cycle the phone, shut down a port or suspend the POE.

If you feel you're having some issues with the switch, please call the SBSC support center at 1.866.606.1866 and please ensure you have your CCOID and serial number of the switch. When you speak to the agent, please provide this community forum post.

-Tom Please mark answered for helpful posts
Cisco Employee

Image bugs

Hello Brayton,

Thank you for reporting these issues on the firmware. In order to better assist you and isolate the root cause, can you please reach out to our SBSC team and open a Service Request? Also, if possible, could you please provide the following details for us to analyze and determine the root cause?

For PoE issue,

  • How many POE devices (and what types) were connected to device before reload?
  • Does issue happen every time device has a soft reset (reset via command not via power cable). Or did it happen only once?
  • Did you see this only on one specific SKU or on all switch models?
  • Show power inline when issue occurs.

For LLDP issue,

  • LLDP Packet capture with working version ( and current version ( – to compare behavior.
  • Show LLDP and show LLDP neighbors for both versions when issue occurs.
  • Can you please elaborate on your comment "No matter what image you use, LLDP doesn't provide VLAN info on initial  switch boot, after a power inline never / auto, and sometimes even after  and port shutdown and power inline never/auto"

Thank you.



Community Member

Image bugs

Thanks Thomas and Nagaraja for writing.   In response to Thomas' question about the VLAN1 address, I went to the IPv4 interface in the GUI, clicked on edit, and moved the radio button to Static and hit Apply.  I would then move to the CLI and show run,  and under interface vlan1 there would be 'no ip address dhcp'  but the ip address and subet mask that was previously assiged by DHCP was not written in the config. So when I would copy run start and reboot at that point the switch would come back with a blinking power light and no way to access the switch accept via the RS232 port. I did so and added ip address  to the VLAN interface and all was well after that. I had to do this on three SG300-28P's.

In response to Nagaraja:  7 Mitel 5330 IP phones, class 3 at about 4300 mW peak power usage per phone. This issue happened only once after upgrading to and only one switch, SKU

SRW2024P-K9 V02

The LLDP issue is not a factor any longer as I am now using a DHCP server to provide the VLAN info and DSCP value, but what I mean by my comment was that the Mitel 5330 would ONLY pick up the VLAN and DSCP value if I plugged the phone in when the switch was fully booted. But it NEVER would if I would reboot the switch, unplug the switch, disable and re-enable power, or shutdown and no shutdown a port.  But unplug the phone and plug it in, it would discover it every time. Since switching to DHCP this issue has gone away completely.

I'm running on all switches now and haven't had any serious troubles. I decided that if it works fine, not to mess with things and upset the balance of life.

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