Network looping Issue, VOIP Phone Deployment
Posted on 2013-11-01
My company has hired an outside contractor to install and deploy VOIP phones in our office. We've been having some issues with the deployment. I have some networking knowledge but I'm limited in being able to explain and understand the problem fully. Our contractor is giving us the run around; I need a detailed technical explanation of why their installation caused our network to crash completely.
Here is the scenario. When our contractor installed the new VOIP phones our entire network was taken offline. I was able to isolate the issue by identifying which ports on our distribution switches had unusually high traffic. I disabled those ports and the network came back online. Prior to me disabling those interfaces we have 99% CPU utilization on our distribution and core switches.
I believe our contractor introduced a switching loop into our network. I need confirmation and more details before I make this accusation.
The contractor is deploying Grandstream GXP2100 phones. I identified two different "loop?" inducing scenarios (by checking what was connected to the switch ports with unusual traffic). The GXP2100 phones have two ethernet connections, one for PC and one for LAN. I understand the live network feed should connect to the LAN port and the PC port can then be used to connect a PC to the phone. In some rooms, I noticed that our contracted connected two live network feeds to the phone. Both the LAN and the Internet port had live network feeds to the distribution switch. I'm not sure what the switching capability of the phone is, or if it has one MAC or two? Would this potentially cause a network loop and can you please provide details?
Another scenario I encountered in a few other rooms was this. In some rooms we have two phones. They were each connected to the network via the "LAN" port. Then, both phones were connected to each other via their internet ports/jacks. This seems like an obvious misconfiguration to me. Can you please provide details on what would happen in this scenario?
I was unable to perform a packet capture as we require 24.7 up time and as soon as I re-connected the phones the network would crash within a few minutes. I understand that would have been helpful here.
Finally, the contractor is deploying 8-port non-managed switched that do not support VLANs. These switches connect to our distribution switch, and the phones are connected to the 8-Port switch. Will we run into trouble in this scenario (are the phones themselves considered "switches")?
Experts, your thoughts and analysis will be VERY MUCH appreciated. Thank you all and enjoy the weekend!