SG300-10MP stops

[alexpons123]

I have a SG300-10Mp with 8 WAP attached, the switch is behind a router and two additional switches. I all comes up and I get wireless Internet at all WAP, but all of a sudden it stops working, the Internet is not longer accessible and its connected to the network, but not Internet access. In fact, the system that was originally connect, indicates no connectivity.

Does anyone have any suggestions on why this would occur, once it has been working for a few minutes?

Thank in advance

Alex

[David Hornstein]

Hi Alex,

it's a interesting mystery novel at the moment, but you have left some unanswered questions.

• Sure would be interesting to see a simple network diagram.
• Are other PC's on other switches still able to get out to the internet ?

Maybe caused by a Wireless loop

• I wonder what the port statistics are showing for the port that is 'uplinked' to the router ?
  • be very interesting to see a screen capture of broadcast statistics on the uplink.
• I wonder if the router or switch thinks there is a spanning tree loop
  • be interesting to see screen capture of the STP state of ports forwarding or blocking ?
  • Is there a broadcast storm in the switch caused maybe by a wireless device creating a broadcast storm ?
  • could be most interesting to see a attached wireshark capture of a few seconds of the switch traffic when the switch goes into a non forwarding state.
• I wonder if by removing a wireless AP one at a time, if  the switch eventually goes back into a forwarding behaviour to the internet ?
  • try removing all AP's from the SG300  and see if after a minute you can get out to the internet ?

switch security

• I wonder if MAC address limits are set or some sort of port security is  set on the SG300 switch ?
  • A copy of the switch configuration would be useful as a attached file so it could be loaded on a switch..

[alexpons123]

Hi david,

Thanks for responding. I am new at this so can you explain what is a wireless loop and a spanning tree loop. You are right about one thing as I remove WAPs the switch begins to forward from the internet. In fact, it works well until, I add WAP 3 (WAP1 and WAP2 working fine) which creates the problem. I will try and get some more information.

Thanks

[David Hornstein]

Hi Alex,

By removing one of the APs the 'storm' within the switch and wireless devices has stopped, only temporarily.

But I would hazard a guess that a configuration option within one of the wireless AP is incorrectly set between maybe two or more AP's.

It may be easier to just reset the AP's back to factory default and only set them up for PC clients only.  It sure sounds from your response that some AP's are bridging some ethernet frames between themselves on the same LAN network segment and causing a broadcast storm within the network segment.

Wireless AP should not create loops between themselves,  unless you configured something called wireless bridging between the AP's  or WDS.

The red line in the picture below,  probably depicts the packet flow of the ethernet frames within the switch.

Packets are moving around the switch and the wireless network, so that there isn't any room for AP wireless clients to get out of the switch to the internet.

One of the symptoms of a broadcast storm could be that the whole local area network or network segment is un-usable, due to the storm condition.

There is a way within these wonderful new switches  to limit the damage caused by a broadcast storm or multicast storm.  But, you really have to fix the configuration issue within your wireless network that is causing a ethernet loop and hence storm or flood of packets. 

Have a chat to your wireless vendor, if you need help identifying the wireless configuration issue,  as i cannot see how the switch is causing this issue.

maybe even point them to this posting.

Have a great festive season with a quiet LAN segment.

regards Dave

[alexpons123]

David, thanks for the response and the great explanation.

This is what the network looks like.

internet-->Netgear wireless router-->Linksys wireless router--->fireBox--------->sg300-10MP

                                     |    |    |                |    |          |    |    |  |

                                    PC1  PC2  PC3              PC4  PC5        AP1  AP2  AP3 AP4

All access points are about 75 feet from each other down a hallway with rooms along each side (concrete walls on either side).

All AP (WAP200) are set as APs (not bridges or repeaters) channel 9 and WPA-personal security, SSID is Tropical for all AP.

I changed the AP's IP to 192.168.1.231--192.168.1.234  respectively and passwords

and the sg300-10 switch to 192.168.1.230.

When I connect the uplink to the switch I cannot access any of these devices, I have to place a static IP on the interface PC (192.168.1.25) and disconnect the uplink to gain access.

I think the access points are configured correctly, everything else is defaults.

And the switch other than the IP and password are default.

What happens is that the uplink becomes inaccessible from the sg300 switch even if I connect directly (wired) to the switch. Starts working and I get an IP address (dyanmic) but all of a sudden it just stops seeing the internet.

Please help.