Free Tools for Network Monitoring and VoIP assessments!
A network assessment and a trouble shooting effort are differentiated only by a matter of time an the level of urgency. Effective network administration means that you are always troubleshooting and always proactively looking for anomalies that can negatively impact the quality of service on your network, trash your voice and video communicates; and compromise the confidentiality and integrity of your data! A network assessment should be a proactive, around the clock activity of monitoring bandwidth utilization, network throughput, jitter, latency and access. This is the process of monitoring the “health” of your network and it is the base line on which we can determine “normal” and set traps and alarms for “abnormal”. Without a base line trend for our network, the only way we would recognize a network problem, is when the users population, beats a path to your door!
When we find an anomaly in our network, a change in the normal trend of traffic and utilization we move into the “who done it” mode. It is no longer useful to know that bandwidth utilization has now exceeded our historically documented level of “normal”. We need to know what protocol is using the bandwidth, what ports are generating the traffic and what is the legitimacy of the traffic. This requires a different set of tools than that which you might use for “health check” related monitoring activities. This is often where we see the difference between “freeware” tools and software solutions that have a hard dollar acquisition cost and a subscription maintenance cost. Bandwidth, Jittery and Latency is one set of measurements. Protocol analysis and simulations an entirely different set of issues.
There are a variety of free tools that can help you setup monitoring for the purpose of “health checks”. Generally, you will want to setup a dedicated “network monitoring” server. Again, there are all kinds of tools on available for this purpose. We recommend that you set up a dedicated monitoring sever, and that you make use of Centos or some other Linux distribution, as most of the serious network tools are written for Unix based machines. For example Cacti, Nagios, Munin and Zabbix are all very powerful health monitoring solutions, with very active community support and software extensions. For those of you who prefer working on Windows platforms, you might consider downloading XAMP for windows! Lets not forget that we have wireless components in our network and we strongly recommend the Xirrus Wifi Inspector be added to your tool kit, though it is only available for Windows.
Most of your key hardware components, including your network switches, routers and firewalls have embedded tools for analysis. For example, seeing that a particular segment of a network is breaching historical bandwidth utilization standards, we can then drill down by inspecting the individual ports of an Ethernet switch. We want to be on the look out for collisions, duplex mismatches, congestion and drop packets! This can be nailed down to a specific network port and that will significantly reduce the scope of our investigation. At this point we want to take a look at what protocols are running on the network and for this we need more specialized tools. We urge you to have WireShark and or Microsoft Network Monitor available and that you be very comfortable in setting it up and also interpreting the information presented. CISCO IOS has a number of advanced tools that can simplify your life. For example, NBAR or network based application recognition, can identify protocols between network segments. Netflow is also a core CISCO analysis tool that many of the freeware programs are built around. Solarwinds will allow you to download and run a fully functioning version of its Netflow analysis tool for 30 days and it covers J-Flow, and other vendor versions of Netflow. Understanding what Protocol is eating up your network bandwidth is an essential debugging step in your network analysis!
Most experienced network administrators will tell you that when it comes to trouble shooting, nothing replaces command line directives. As that great Yogi Berra would say; “ You can observe so much by watching”. Make liberal basic iCMP commands of ping, traceroute and arp and also NetStat for machine specific path analysis. A useful desktop tray tool for machine specific analysis is NetWork also free for the download. On your Unix machines you can run the command line “iftop” which will show bandwidth utilization by IP and port. There are also a number of online network tools and free downloads that can help you trouble shoot issues. These would include IPChicken for determining what IP address you are presenting to the outside world; and angry IP port scanner.
A first time network assessment will looking at all of the above metrics but will also include physical level checks, and simulations of what future VoIP traffic might look like. DrVoIP publishes a VoIP Network Assessment and readiness checklist that is available for free download in your membership portal! Send an email request to DrVoIP and request a sample Statement of Work for a Network VoIP readiness assessment and we will send you one.
At the end of the day, a VoIP deployment will be as good as the network it is build on! It is all about the network!