SG500 Port up and down

[Hubsi-Smith]

Hello,
we have an old Cisco SG500 Switch and there is one port a trouble-maker.

The environment looks like: AP <-> Cisco PoE Injector <-> SG500

The log file contains permanently up/down´s on the port with the AP/Injector is connected.

The Port goes up... 10 minutes later the port goes down and comes up again within 5 seconds. Then it is up for 8 minutes and goes down again... and so on...

I checked the mac address-table and the AP has no entry there. I can´t reach the device with its ip-address during the port is up.

the AP is located in our Field Office 600km away.

Could it be a cable problem if the port is up over several minutes? Does the switchport show connected when port is up on the PoE Injector or AP. Is the PoE injector invisible for the switch?

Could it be that the AP falls back to factory reset... but even with the default ip, the AP sends frames to the switch and the mac address table will show that device. But in my case no entry in the mac address-table.

I am a bit confused and what do you think should I check first?

[marce1000]

   - Check the  logs on the access point when this happens.

 M.

[balaji.bandi]

There are many reasons, Maybe AP try to Join the controller Failing? 

Is this worked before and failed?

1. Does the switch has enough power to boot AP?

2. what AP model is this?

3. Does anyone local confirm is the AP shows any lights?

4. how is this connected to WLC ? (wherre is WLC?)

5. Any other AP on the site and working ?

[Hubsi-Smith]

1. Does the switch has enough power to boot AP?

 -> between Switch and AP is an Cisco AIR-PWRINJ6

2. what AP model is this?

 -> we provide only the network infrastructure. AP self is managed by third company

3. Does anyone local confirm is the AP shows any lights?

 -> there is a camera wall mounted. I can see on the LAN connectore are blinking the orange and green leds. AP is only a 10/100 mbit device

4. how is this connected to WLC ? (wherre is WLC?)

 -> standalone device

5. Any other AP on the site and working ?

 -> only device connected on the switch

When switchport is up, does it show connection to the PoE Injector or the AP? Does the PoE Injector only do a pass-through?

Btw, when LAN port on the AP are blinking/flashing orange and green, could it be a wire/cable issue?

[balaji.bandi · Accepted solution]

STAT (port status)	Off	No link, or port was administratively shut down.
	Green	Link present.
	Blinking green	Activity. Port is sending or receiving data.
	Alternating green-amber	Link fault. Error frames can affect connectivity, and errors such as excessive collisions, cyclic redundancy check (CRC) errors, and alignment and jabber errors are monitored for a link-fault indication.
	Amber	Port is blocked by Spanning Tree Protocol (STP) and is not forwarding data. Note After a port is reconfigured, the port LED can remain amber for up to 30 seconds as STP checks the network topology for possible loops.
	Blinking amber	Port is blocked by STP and is not sending or receiving packets.

[Hubsi-Smith]

Hello,

here the solution, the AP had a malfunction. New one works flawless