ImageStream IS Gateway and Rebel Routers

Gateway and Rebel Routers from ImageStream Internet Solutions: heavy-hitting performance, lightweight price.

Or, if not lightweight, at least inexpensive, compared to their mainstream competition. ImageStream's backbone routers spring from a simple premise: take GNU/Linux, with all of its proven networking abilities, and package it in an industrial-strength wrapper. Simple premise, perhaps, but far from a simple accomplishment. Fortunately, ImageStream has had plenty of practice. Founded in 1993, they have been building Linux-based servers and routers long enough to know what is important.

Packing support for a wide range of physical interfaces, up to T3 and beyond, and enough expansion room to cram over twenty T1s, multiple Ethernet and a couple of big WAN connections in a fully loaded system, ImageStream has taken their simple premise and made it into a useful reality. Dynamic routing with RIP1, RIP2, OSPF and BGP4, bandwidth management, firewall support and seamless interconnectivity with Cisco and other major name routers make the accomplishment even more impressive. A price point well below Cisco's makes their reality compelling.

In order to build their routers, ImageStream first created a Linux distribution: one that maximizes network functionality while minimizing hard-disk space requirements so it fits nicely on a solid-state flash hard disk and has easy-to-use administration tools. You don't need to be a Linux guru to set up or maintain the system. Then, they developed and released, under the GNU GPL, an open-source Linux kernel extension called SAND, Standard Architecture for Network Drivers, which allows binary distribution of WAN hardware and protocol drivers. SAND is a compromise between the open-source ideal of always having open source, and the closed binary-only drivers that have caused so much trouble in the computer industry. It is a necessary compromise for routers, because many WAN drivers need to contain code or protocols licensed from companies that don't support open source.

The most significant feature of SAND is its ability to mix and match binary protocol, WAN card and even external CSU/DSU drivers from different manufacturers. This means a protocol developer can release a driver and have it work with any WAN card that uses SAND drivers, and a WAN card producer can release a driver to support its hardware knowing the various protocols will be supported. SAND also provides a standard method for configuring and monitoring varied WAN interfaces, simplifying performance and bandwidth monitoring across multiple interface types.

ImageStream's compact and network-heavy Linux distribution, when married to an industrial-quality rack-mount PC, becomes a high-power router fully capable of meeting the backbone routing requirements of ISPs, schools, businesses and anyone who's ever considered the benefits of a private T3 Internet connection to their home. Despite their PC heritage, these routers give a first impression far removed from the usual desktop-PC chintz.

I looked at two of ImageStream's routers, the Gateway and the Rebel. The main difference is in the physical size and level of expansion. The Gateway has twelve available PCI slots for WAN or LAN cards; the Rebel has four. Which router is right for a particular network application will depend more on current need and projected expansion than on differences in core functionality. Though it was not tested, parts of this review also apply to the ImageStream Enterprise router, the biggest of the line with 18 card slots.

Both of the routers tested are based on a single-board computer with integrated 100MB Ethernet. Additional network interfaces are added using PCI WAN and LAN cards, which plug into a passive backplane. Interfaces range from V.35 ports to HSSI and ATM, and can be pre-installed or user-added. The chassis are standard industrial 2U and 4U rack-mount PC cases and are available with dual hot-swappable power supplies for an additional $500 US. Adding interface cards to the Rebel requires removing fifteen screws, which must be a record. A far more reasonable four screws grant access to the Gateway. In either case, once opened, access is excellent.

Included with the ImageStream router is a slender manual made up of a quick-start guide, a configuration guide and an appendix (the largest part of the manual) filled with handy information, such as cable-wiring diagrams, subnet-mask tables and troubleshooting information. At first glance, the manual seems downright sparse, and a second glance will confirm that impression. However, the manual does one thing beautifully—it tells you what you need to know. It assumes you know how to mount the chassis in your rack and which end of the cord plugs in the wall. It tells you how to access most of the unique features of the router and how to fix the things that are likely to go wrong. It is hard to complain about that, but compulsive manual collectors will be frustrated by how unimpressive the ImageStream manual looks next to a stack of Cisco books. The most noticeable hole was in the instructions for configuring dynamic routing—there were none. If you intend to use BGP, RIP or OSPF, a book on configuring GateD or a visit to http://www.gated.org/ will be essential.