As VoIP becomes more popular and gets deployed on enterprise networks, the need for QoS (Quality of Service) becomes much more critical. Many enterprises have invested many thousands of dollars in their networking infrastructure, including networking switches, routers, and more, so they are hesitant to throw all that equipment out just to add QoS-enabled network hardware. PowerNOC offers a bandwidth throttling and QoS management product that works in conjunction with your existing legacy network hardware to enable QoS functionality.
Can set guaranteed
Limited prioritization of VoIP traffic
No alerting function
Support for “state” would be good addition
PowerNOC’s Bandwidth Manager comes in two flavors — Basic Version and VoIP/QoS Version (see feature comparison chart). Essentially the two products have nearly an identical feature-set with the main exception being that the VoIP/QoS model also supports prioritization of VoIP packets. For obvious reasons, we decided to check out and test the VoIP/QoS Version due to its more advanced VoIP capabilities.
The Basic version is essentially a simple bandwidth manager that throttles the maximum upload and downloads speeds of any IP based equipment. It utilizes a Web interface to configure all of the speed settings. It works as a bridge, so there is no need to change your current network settings. You simply put the box near the Internet gateway/router and you’re ready to go.
According to their manual, the VoIP/QoS Version has all of the features of the Basic Version plus you can set what types of services, such as VoIP, get a high or low priority (See Figure 1). We should point out, that it doesn’t have to be VoIP — you can set specific ports, such as Web traffic (port 80), or FTP traffic (port 21) to have high or low priority. You can also set a guaranteed bandwidth for each IP addresses and/or services. The product records the traffic usage of every IP address and you can then view a report of everyone’s usage in real-time. Graphs (See Figure 2) are created that show the daily, weekly, monthly, and yearly usage of each IP address. (Graphing is limited to 500 IP addresses.)
When testing the unit we discovered that the Bandwidth Manager doesn’t truly prioritize VoIP traffic. The Bandwidth Manager can only prioritize packets based on the port number or the IP address — it cannot be stateful and monitor SIP or H.323 traffic to determine which RTP ports (usually dynamic UDP ports) are to be given the highest priority during a VoIP call. The RTP traffic is the actual voice traffic and requires prioritization. Since the RTP ports are usually dynamic UDP ports, in order for “true” VoIP QoS, this product would need to be able to maintain “state” and determine which UDP ports are utilized for the RTP voice streams. We should point out however that it can guarantee the QoS for the call setup for SIP; for example, simply by assigning port the common SIP port (5060) a high packet priority.
Of course, if you are using VoIP phones with static IP addresses, then you can use this product to guarantee bandwidth for VoIP calls and ensure QoS for these critical high-priority IP phone devices. But you can just as easily buy the less expensive “PowerNOC Basic version” to do that as well. Alternatively, some VoIP devices do let you specify a range of UDP ports to use and you can then prioritize those port numbers as well.
Room For improvement
Saving the graphs to a .CSV file would be a nice addition. Perhaps an e-mail alert if the device detects a huge spike in network utilization — often an indication of a virus or intruder — would be a nice feature addition. We mentioned earlier that the product doesn’t support maintaining “state.” The ability to maintain “state” would no doubt add a lot of cost to the unit, since it requires much more processor horsepower to ensure timely packet analysis and delivery. Nevertheless, we do feel there is a market for a turnkey, plug-and-play product that can determine VoIP traffic and prioritize it accordingly. So perhaps they should add this to a future version.
The reporting was decent and the Web interface was easy to navigate. The product performs well in doing IP address and service port prioritization and QoS, but it falls short of truly providing QoS for VoIP network devices since it cannot maintain state and determine dynamic ports “on-the-fly.” Nevertheless, if you are looking to perform IP address or service port prioritization, then this product certainly will do the job and do it quite well.
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