The Itheon Network Emulator (INE) is something we’ve come across before at Techworld (we reviewed the previous version last July). Back then, this was the only emulator product in the range and, although it was very powerful, we moaned that it was a bit pricey.
The INE range has now expanded considerably. The previous model is now just one part of the range, and is called the INE Enterprise. The new range also includes INE for Windows (which, as it sounds, is a software package that you install on your Windows machine) and the new beast we’re looking at here, the INE Compact.
The purpose of a network emulator is simple: to mimic the behaviour of a real-world network, generally a WAN, simulating data rates, delays and errors, without the need to invest in the actual network connections. Emulation is ideal for organisations that want to try out new systems and applications without letting them loose on the corporate WAN; similarly it’s useful to those that want to install a WAN but want to quantify the required links properly instead of simply guesstimating what they need.
INE Compact is a small black Intel-based chassis that comes pre-installed with Windows XP Home Edition and the INE software. You can connect a screen, keyboard and mouse if you wish, but we (and Itheon, for that matter) reckon most people will run it “headless”, choosing to manage it via VNC (which is pre-installed) or Itheon’s own INE Console application. The unit’s not rack-mountable, but this is a good thing since although some people might want to leave it in a rack, others would prefer a nice portable unit that’s easy to shift around the lab.
The unit has four Ethernet ports. Ours came pre-configured with ports 1 and 2 as the in/out ports for emulation, and with port 4 on IP address 192.168.0.215 so we could connect to it for management purposes. You can choose which ports are to be used for the emulation using the very simple Options dialog. It should be said at this point that the unit is black and very sexy with cool blue lights on the front – factors that are perhaps less relevant than functionality and reliability, but it’s a nice touch.
You administer the system using the aforementioned INE Console application. You can buy the Console and install it on your desktop PC, but most people will probably simply VNC to the Compact and run the Console that comes pre-installed on it. When you run up the Console, you first need to hit Connect and point it at the device you want it to manage (generally itself). Once you’re connected you have three key parameters that you can change either by moving on-screen sliders or by entering specific figures into the text box beneath each one. From left to right, the sliders control the raw bandwidth of the simulated connection, additional delay (i.e. latency) and packet loss. Within each slider pair, one controls incoming (downstream) bandwidth and the other outgoing (upstream) – essential if you want to emulate an ADSL link, for example.
So you can save your settings, INE uses the concept of a “scenario”. A scenario is basically a set of parameters within which you can vary the precise settings at will. So for an ADSL link you might say that the upstream bandwidth can vary from 0 to 256kbit/sec and the downstream speed from 0 to 8Mbit/s; the sliders on the screen then constrain you within the minimum and maximum values for each parameter. Within each parameter in a scenario you can tell the system what constitutes “good”, “average” and “poor” performance, and the rating for whatever values are selected at the time is shown on the screen. Personally I didn’t see a great deal of value in this feature (I like to work on raw numbers, not some arbitrary rating of “average”) but some users might like it and if you don’t want it, you can just ignore it. You can also configure filters that allow packets to be allowed/dropped/delayed based on their IP address, port or protocol. There’s a shedload of in-built scenarios (you can pick from a list), and if you want to spend a bit more money you can also use a “scenario server” – a separate box on which you can store scenarios so that you can use them from multiple instances of INE. If you want to create your own scenario, that’s just fine – just change the settings and hit “Save As…”.
Although all the interfaces on our unit came with IP addresses defined, the addresses are not actually relevant to the emulation process – the device simply passes the packets through with no IP-level work done at all. So although LAN1 had address 220.127.116.11/8 and LAN2 had address 18.104.22.168/8, our pair of test machines ran perfectly happily using a 192.168.0.x/24 address range. The throughput of the unit matched the settings pretty well when we tried it in the lab. For instance, an emulated 2Mbit/sec downstream, 256kbit/s upstream ADSL link with 15ms latency gave an average upload speed of 1902kbit/s and an average download speed of 249.92kbit/s for FTP transfers (remember you have to allow for a bit of traffic overhead on top of that for the headers and FTP protocol stuff).
The unit itself is limited by software to 10Mbit/s, as you’re informed by an alert box if you try to define a bandwidth limit greater than this. The hardware and OS seem to be able largely to keep up with the configured settings – so cranking the ADSL up to 4Mbit/s gave us 3785kbit/s, 6bit/s gave 5721kbit/s, and 8Mbits/sec gave 7114kbit/s. Things only started to tail off significantly when we got to 10Mbit/sec on the slider – the throughput came out at 7655kbit/s – but having discussed this with Itheon's techies, we reckon that this behaviour is down to the latency of the emulated link (15ms in each direction) becoming increasingly significant as the link speed grows, not some arbitrary limitation of the emulator itself.
When it comes to finding negative things to say, there’s nothing tremendously serious wrong with the unit. The first idiosyncrasy is that the motherboard of the unit seems to be designed for a laptop with an in-built screen. This means that: (a) it thinks it’s got a built-in display as well as the socket for an external one; and (b) if you start it up without a screen attached, it tends to forget you ever had an external screen and then won’t display anything the next time you connect one. Itheon was up-front about the problem, though (that is, they warned me about it rather than waiting for me to find out the hard way) and to be fair it’s a Windows issue, not an Itheon one, and they’re working on a solution.
Another niggle is that the manual doesn’t really cover the Compact in any great detail, though again Itheon says this will be sorted in a new revision of the manual (and anyway, all you really need to know is the basic things like the default IP address of the unit and such like – the GUI is self-explanatory). Next, when you pick the interfaces you want to use in the Options box, it doesn’t give you any clues as to which interface is “outside” and which is “inside” as far as the asymmetry goes – so in an asynchronous network scenario there’s a 50 percent chance you’ll plug the cables in the wrong holes. The final negative point is that the GUI isn’t particularly fast to respond, but this is presumably because the packet-passing code has mega-high priority for CPU and network time and everything else takes a back seat, so it’s to be expected (and you don’t use the GUI very much anyway, so who cares?).
Although INE Compact doesn’t have as many features as its Enterprise big brother, the price tag reflects this – and anyway, the basic parameters of throughput, latency and packet loss are all that most users will want, and the concept of defining “scenarios” and the inclusion of filtering capabilities is handy too. It’s easy to configure, and the appliance is sensibly chosen as it’s portable and silent. A nice addition to the lab of any IT person that wants to try stuff out in a sterile environment before doing it for real.
If you want complex emulation, sweet-talk the FD and look at the Enterprise version. For the stuff that most users need, however, the INE Compact is the one to look at.