When it comes time to dissect a network problem, whether the problem is related to security or performance, a deep look into all the network activity surrounding the incident can be critical to resolving the issue. An intrusion detection system, with its rules for capturing problematic network events, can be of some help, but for real problem diagnosis or forensics, you need more. Network Instruments' GigaStor is designed to meet that need with full traffic capture that extends backward to hours or days. This "keep it all" capability makes the GigaStor a valuable addition to any network for which high performance, security, or regulatory compliance are critical issues. When you need to investigate a network slowdown, a security breach, or anything else that happened on your network, if you know when it happened, then GigaStor can take you there.

The Bottom Line Network Instruments GigaStor Network Instruments, networkinstruments.com Very Good  8.6 criteria score weight Analysis tools 8 20% Performance 9 20% Scalability 9 20% Ease-of-use 9 15% Manageability 8 15% Value 8 10% Cost: Starts at $19,995 (4TB storage, 2 ports); as tested (8TB, 4 ports), $35,000 Platforms: GigaStor appliance based on Windows XP 64; Observer analysis software runs on Windows XP or Windows Server 2003 Bottom Line: GigaStor is Tivo for your network. The ability to play back the traffic from any given time in the observed life of the network is critical for advanced forensics and problem solving. The Observer software puts a long list of analytical tools in the hands of security and network engineers, making life easier for both groups as they work to solve problems on the network. Plan to buy as much storage in the GigaStor as your budget will allow. The system is far from cheap, but its value lies in the data it stores, so more is definitely better. About our Reviews and Scoring Methodology

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GigaStor is, essentially, a large box of great storage capacity (from 4TB to 48TB) with high-speed network interfaces on the outside and the capability to rapidly move data between NIC and disk within. I tested a "small" version of the GigaStor, with 8TB of storage, four Gigabit Interface Converters, and three 10/100/1000Base-T interfaces, and the IO necessary to reach the device, all packaged in a 6U box. All the hardware would be much less useful without software to analyze the data gathered, and Network Instruments does not disappoint: GigaStor includes the company's Observer software (version 12 in this case), which serves as your window into the GigaStor's stored information. In addition to providing analysis from GigaStor, Observer can gather data from multiple GigaStor appliances and perform correlated analysis across all the instances. Network Instruments recommended that we run Observer on a Windows XP or Windows Server 2003 system, with a minimum 2GHz processor and at least 2GB RAM. Our test platform met or exceeded all the recommended specifications.

Interestingly, Observer isn't the only piece of the GigaStor solution that runs on Windows. Whereas most network and security appliances use Linux as the embedded OS, the GigaStor sits on Windows XP 64. When I asked why Network Instruments chose Windows XP 64 as the platform, I was told that it had to do with their developers' experience -- an absolutely valid reason for reaching a decision. In our testing, we had no issues with the device, no concerns about performance, and no problems with the operating system. I give you this information because it's unusual -- not because it was a problem.

The roughest part of installing the GigaStor was picking up the box to install in the rack. After the hard disks were installed in the chassis and various cables plugged in, I moved straight to software setup. I began by discovering the network devices. For the GigaStor system this is a passive activity performed by listening to network traffic, not scanning ports. This is a good thing if you aren't the Tripwire jockey for your network. After I built an accurate description of our test network, I began to set up filters for the activities and the criteria I wanted to set for alarms. The Observer software allows you to include or exclude traffic based on packet type, addresses, address pairs, traffic level, behavioral rules, and most other factors that can reasonably be considered for this kind of task.

Remember that time at 23:49?

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The real power of GigaStor emerges when you begin examining the packets you've captured using some of the embedded analysis and replay tools. The analysis takes place in an Observer main window, using a straightforward tabbed interface. In the control panel tab, you get a graphical display of network activity (a rough activity level line graph) with a timeline across the top. You can click on a range of time (from hours down to milliseconds) and run the expert analysis tool on the network traffic. Here you get a detailed breakdown of the traffic contents and you can reconstruct and replay contents, including VoIP calls, certain streaming media types, Web sessions, and instant messaging, allowing you to listen to phone calls and streamed audio and view Web pages and video just as the user heard and saw them. There are some limitations to the playback capabilities, but they're common-sense restrictions. Observer won't, for example, decode SSL tunnels unless you provide the key.