LOSTCIRCUITS

Inside the Nexland ISB Pro800Turbo
The two WAN ports are connected to one RealTech Ethernet switch each that feed the data into the AMIC ASIC that provides the Load Balancing. Two 16 bit wide EliteMT -6 memory chips combine to a 32 bit path. The actual computation load is done by a Samsung 50 MHz ARM processor. On the LAN side, a fully integrated 0.22 µm fab Broadcom BCM5318KQM LAN switch provides DHCP and routing of the packages to the appropriate port. The firmware is a 512 Kb Flash memory chip which is only about 1/4 of the density of the normally used firmware devices but suffices because of the streamlined software. Moreover, because of the lower density, the Flash device is faster than larger chips.

So how do they do it? We used our favorite tool, that is a screwdriver to open up the router and peek inside.

Centerpiece of the ISB Pro800turbo is the Samsung ARM processor running at 50 MHz which offers enough power for any home and small business user to process the information of which data are valid and which are not. Since the data need to be written to local on-board memory first before they can be allocated to the appropriate LAN port, the speed and quality of the internal memory is a critical component in the overall performance of the router. Interestingly, what we see inside of the ISB Pro800turbo are old acquaintances from the high end graphics sector: two EliteMT -6 x16 chips provide a 32 bit memory path for superbly fast read writes. What was puzzling at first was the fact that a 150 MHz rated memory is paired with a 50 MHz processor / bus speed. However, as we learned from Nexland, it is less expensive buying a single bin of high grade components and use them even in the enterprise sector than having the overhead of multiple component lines.

The core of the routing department of the ISB Pro800turbo is the Broadcom BCM5318 8-port 10/100 switch with on-chip 256 kB packet buffer, which combines all the functions of a high-speed switch system into a single 0.22µm CMOS device:

• 256 KB packet memory buffer
• 8 10/100 IEEE 802.3u compliant transceivers
• Nine IEEE 802.x compliant media access controllers
• Address management
• Non-blocking switch fabric

The two WAN ports are enabled by two RealTech Ethernet controller chips. One of the key components to performance of the Nexland line of product is the 512 kb Flash memory holding the firmware. Most other providers have higher degrees of redundancy in their software which makes higher densities of flash memory necessary with the known drawback that larger is slower.

Above we mentioned that Nexland uses a single line of component supply for all their products to cut down on stocking overhead. The justification of using high end components is that the more advanced Nexland devices are using hardware acceleration for the current internet security protocols such as VPN. Hardware acceleration can increase the performance of the security features by about 5 x, that is, for virtual private network connections that depend on high bandwidth data exchange, hardware acceleration will in fact speed up the data exchange by a factor of 5 x, which is nothing short of breathtaking. In order to keep up with this kind of traffic, the rest of the components need to match the capabilities of the HW -accelerated security features, hence the 150 MHz memory and the high-end Broadcom switch. What it all boils down to is that with buying one of these puppies, you get a drag racer with the NOS injector removed, everything else is there and you get it for the price of a street car.

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