FEP Architecture FAQS

Isn't your Front End Processor just another MLAD solution?

Absolutely not. While the implementation does in fact use an MLAD software component, it would be a mistake to characterize the TCP/Link FEP as an MLAD.

An MLAD is essentially a bus adapter solution, allowing you to interface an PC LAN card to the I/O bus of the Tandem host system and to send NETBIOS NCB's from the host to the LAN card.

A TCP/Link FEP provides an order of magnitude more functionality. Low level TCP/IP protocol events are handled by TCP/Link software running in the FEP where the MIPS are cheap and fast.

The net effect of this FEP architecture is a TCP/IP solution that is both much faster and far more cost effective than an entirely host based solution where all of the TCP/IP and Ethernet handling is done on the host itself.

What kind of performance advantage is there to the FEP architecture?

The significant performance and cost advantages associated with the FEP architecture are detailed in our publication "Achieving High Performance TCP/IP on your Tandem System."

Why is CPU consumption so important?

There are actually two reasons.

The first is that host CPU's cost money, typically far more than a FEP. By using a FEP, the customer can accomplish more TCP/IP processing at a lower cost than if the entire protocol stack were run on the host.

The second reason is that during periods of relatively intense TCP/IP activity using a host based implementation, heavy CPU utilization is always the result. Since CPU's are busy doing TCP/IP processing, far less capacity is left to do application processing. As a result, application impact is inevitable, causing users slower response time and degraded levels of service.

One Tandem Himilaya K10000 user recently reported that by converting from the host based TCP/IP to the TCP/Link FEP TCP/IP, CPU utilization dropped from 90% to 8% and the application impact went from "terrible" to "unnoticeable."

How is a FEP implemented?

A FEP is implemented by combining a PC computing engine with the TCP/Link LAN Interface Package.

The computing engine may be any PC system. A 386 or better processor with 2MB of memory is recommended.

The TCP/Link LAN Interface Package is a combination of a high speed Ethernet card with onboard processor and memory as well as TCP/Link software which implements the Front End Processor functions.

We sell a bundled FEP product which combines these two items in a convenient rack mounted system package. Alternately, if a customer desires to provide his own computing engine, the TCP/Link LAN Interface Package is separately available.

Irrespective of which option is chosen, the TCP/Link Base Software Package must be licensed from Failsafe and Tandem product #5622 MLAD Kit must be purchased from Tandem. Contact Failsafe for further details.

If FEP's are so great, why did you implement the TCP/Link PLUS product line?

Because some customers simply do not seem to be concerned about performance, but are still interested in the various TCP/IP services afforded by the TCP/Link product line.

As a result we have positioned the product line to allow customers to choose between the high performance FEP version or the Tandem TCP/IP compatible version of any of our services.

Can we actually try out this product at our site?

A product demonstration at your site can be easily arranged.