Managing a VoIP phone system requires a different set of tools and skills than you needed for TDM systems. Likewise, having voice running over your data network requires new tools to have visibility into what havoc these new protocols may be wreaking on your LAN or WAN. Let’s take a look at a low-cost set of tools that will help you manage this new environment.
You Need Analysis
Network analysis is way easier today than it used to be. Back in the 90’s we had to lug around a Network General Sniffer. You had to have the right transceiver to connect to the type of network cable being used. (Anyone remember vampire connectors for thicknet?) In the late 90’s an open source project named Ethereal was started to allow the use of PCs for network analysis. In 2006, the project changed its name from Ethereal to Wireshark. Today, Wireshark is a mature, stable and feature-rich network analyzer. It is powerful enough to be your general-purpose network analyzer, but also has the specialized VoIP features you will need for troubleshooting voice on your network. Wireshark shows you all of the call setup/tear-down SIP messages so you can monitor call progress real-time. It has graphical displays to help you make sense of the call progress. It also monitors the RTP traffic and can record and play back the audio so you can track down call quality issues. This should be the primary tool in your VoIP toolbox.
The Hub of Activity
A good, old-fashioned Ethernet Hub
Yep. In a switched Ethernet network environment, traffic from an individual device is not visible everywhere. So when you want to use Wireshark, you typically have to set up a mirroring port for whatever port you want to analyze. Modern VoIP phone systems may also provide a mirrored port at the IPPBX. But these solutions require administration, require you to be in that central location and in the heat of battle, it may just be easier to unplug a cable at the phone, insert a hub and get on with it. Fortunately, there are lots of old hubs sitting around - you may be able to find one on a shelf somewhere. An old un-managed 4- or 8-port 10/100 hub works fine and easily stows away in your laptop case or toolkit.
Plotting Your Revenge
Don’t let the name fool you. Two of the primary enemies of good VoIP voice quality are latency and jitter. PingPlotter is the ideal tool for tracking down either of these problems. PingPlotter gives you a graphic display of the route your data takes between client and server. It allows you to track a route over a long period of time, so you can characterize a path (LAN or WAN or both) and identify when/where problems are occurring. There are three versions of PingPlotter - the freeware version, the standard version and the pro version. The pro version allows you to track multiple targets simultaneously, runs as a windows service and has lots of other features that make it worth the (low) price.
Have you tried these or other tools? What tools do you use on a regular basis? What could you recommend to our readers? Share your thoughts in the comments.