Outages

[danrhodes]

Hi All,

 

Having some trouble with network outages in one of our buildings.

 

At approx 12:04 - 12:20 everyday the network in one of our buildings dies, not started to look in depth into this yet so just wondering if anybody has any ideas?

 

D

[tmcd35]

Sounds awfully precise in the timing, also sounds like lunch time. Any staff facilities near the switch in question? Either someones plugging in a kettle (or bank of 30 laptops) and tripping the mains. Or Someone is unplugging the switch to plug in a kettle/microwave/hoover/laptop.

 

That'd be my first guess.

[Jamman960]

If its a managed switch I'd check its uptime to see if its power is being cut , if the power is not being cut I'd use wireshark on a machine connected to the switch to see whats going on during the outage.

[markberry]

We had a similar issue once. A student kept plugging a patch cable in to 2 live network sockets. Created a loop and took part of the network down. Took ages to locate the offending cable.

[tmcd35]

We had a similar issue once. A student kept plugging a patch cable in to 2 live network sockets. Created a loop and took part of the network down. Took ages to locate the offending cable.

 

I've had this a few times, which is why I make sure spanning tree is turned on on all my switches (limits the effects of the resulting storm).

 

I'd say if this is the cause you have one mighty kind troublesome student! To cause the loop and then 20 minutes later unplug it again. In my experience when students do this the cable is left like it until one of the technicians find it.

[danrhodes]

ive noticed that shadow copy runs on our PDC and SDC at 12pm could this affect it, ive changed it to run at 12:30 to see if it happens later.

 

Dan

[danrhodes]

Looks like it may have been some excessive jabbering on one of the ports of a switch in ICT. I have heard that this can be cased by EMI has anybody ever heard this before?

 

 

D

[OutToLunch]

Looks like it may have been some excessive jabbering on one of the ports of a switch in ICT. I have heard that this can be cased by EMI has anybody ever heard this before?

 

Far more likely to be misbehaving equipment on the end of the port than it is an interference issue. Did you get as far as using Wireshark to check the actual traffic or just unplugging a lead and finding things worked again?

[danrhodes]

Yeah I use Wireshark and Agilent Network Analyzer Software to monitor traffic.

 

We have a strange pattern at the moment for Multicast traffic, its going from 1/2 to 330/350 every few seconds and then back down again, we do have a fair amount of workstations so it may be some streaming media?

 

D