Out of the Box

Rebel Router is an Intel-based platform running ImageStream's Enterprise Linux with the 2.2 kernel. In our tests, we found the device setup and configuration simple and straightforward, but we have considerable experience with Linux routing software. If we had knowledge of only Cisco Systems products, for instance, we would have had a difficult time getting the first packets routed. ImageStream will, however, convert access lists to ipchains/ iptables and promises a one-day turnaround to do so, though we didn't have a chance to verify this.

We connected a Microsoft Windows-based PC to Rebel Router's serial port, logged in and began establishing parameters using the simple menus in Rebel Router's configuration interface.

Our serial connection provided one heart-stopping episode: We sent a massive flood of exceptionally bad packets to Rebel Router's DS-3 interface, and Rebel Router crashed. When we rebooted, the router wouldn't complete initialization, leading us to suspect hardware problems. On the advice of ImageStream's technical support, we unplugged the serial cable, rebooted and -- voila! -- Rebel Router returned to life. It turns out that there's a known issue between Rebel Router and Windows' HyperTerminal communications software when HyperTerminal is used as a terminal emulator via the serial port. We switched to TerraTerm and had no further problems. In fairness to ImageStream, we've had similar problems between HyperTerminal and other embedded devices -- apparently HyperTerminal sends a setup string that can prevent some systems from completing initialization.

Vendor Information Rebel Router, starts at $1,999. ImageStream Internet Solutions, (800) 813-5123, (574) 935-8484; fax (574) 935-8488. www.imagestream.com

We configured Rebel Router using the supplied software, which includes GateD, IPsec and OpenSSH. Rebel Router is managed through the Linux SNMP MIBs, also included in the software distribution. ImageStream has not written proprietary MIBs for Rebel Router.

My Kingdom for a Processor

ImageStream advertises Rebel Router for low-cost wire speed DS-3 routing. The system shipped to us had a 802-DS dual DS-3 board and a 522-T1 dual T1 board installed. When routing between the two DS-3 interfaces, Rebel Router is capable as a wire-speed DS-3 router, as long as there is one and only one DS-3 interface in operation. We tested Rebel Router using a Spirent Communications Adtech AX/4000 server running the Layer 3 DS-3 cards and the 1-Gb analyzer/generator modules. For packet sizes, we used a Markov (center-weighted) distribution, ranging from 512 bytes to 1,024 bytes. Routing from a single DS-3 interface to Rebel Router's single Ethernet port, we achieved packet rates of more than 37 Mbps. We ran additional tests using a random distribution between the two limits and got similar results. When you allow for the IP and BGP (Border Gateway Protocol) packet overhead, the test results indicate that ImageStream's "wire-speed routing" claim is justified.

When we tested routing between the two DS-3 interfaces, we reached only 43 percent of wire speed with the first interface. Rebel Router's Celeron CPU is likely the limiting factor for DS-3 performance, since the second DS-3 interface could handle only 60 percent of the traffic passed by the first. ImageStream recommends the system for single DS-3 installations. This advice should be followed.

With the software on Rebel Router, you'll also be able to bond the two DS-3 ports into a single logical channel. The bonded DS-3 performance should make Rebel Router a serious contender in high-burst traffic applications.

With performance defined on the top end, we were interested in how easily we could set rate limits on the DS-3 interface. Hotels and other sites with widely fluctuating data needs frequently buy bandwidth on a basis of limited average use with support for bursts. With Rebel Router's open-source capabilities, configuring the limiting process requires only a few minutes work, and services like cron (a Linux scheduling application) let you establish rate limits that change at predetermined times. Although we did not test rate limiting, GateD lets you restrict bandwidth to individual ports or users, which means total bandwidth allocation can be based on priority or accounting considerations.

Bargain Features

Rebel Router's open-source support makes adding features and services very easy. You can add any service for Linux--authentication, firewall, QoS (Quality of Service) or compression--to Rebel Router; you're limited only by the storage space on the router's Flash drive and RAM for application loading. Although you're responsible for managing these added applications, the flexibility increases Rebel Router's potential return on investment.

Good News Quick-change ability. Leverages open-source Linux code. Modular software design. Bad News Online documentation out of date; printed version costs extra. Known issues (such as HyperTerminal problem) not noted in documentation. No dual power supply.

The system's Flash holds all configuration information, but it can be a point of failure. ImageStream provides insurance in the form of the SCP (secure copy) function, which is part of the OpenSSH that ships with the system. SCP allows copies of the Flash to be stored off-site, so you can retrieve them in case of physical damage or a successful attack.

We like Rebel Router, though there are some caveats. If you need a router with wire-speed performance on multiple DS-3 interfaces, look elsewhere. Also, ImageStream doesn't ship paper documentation with Rebel Router -- users are directed to the company's Web site for manuals -- though printed copies are available for an additional charge. Some sections of the manuals are versions behind the software shipping with the product. ImageStream technical support, on the other hand, is quite good, providing rapid, accurate answers.

Since we tested Rebel Router, a couple of things have changed. The 802-DS dual DS-3 card has been replaced by the 522-DS card. ImageStream says the product's performance has improved, and the price has been reduced to $1,999 from $3,140 (as tested). The company also is beta-testing a new version of its Enterprise Linux, using the 2.4 kernel, which should provide performance and functionality improvements. In addition, the cxompany has begun shipping Rebel Router with 128 MB of RAM, rather than the 64 MB of our test unit.

By combining low price, good performance, flexibility and expandability, ImageStream has made the Rebel Router a solid boundary router for the price of an intranet router.