Why Front End Processor Architecture?

Performance, Speed, and Cost Efficiency!

The TCP/Link product has been implemented using a Front End Processor (FEP) architecture. Each FEP provides for the support of low level protocols and functions, thus relieving the valuable host processor of much of the communications burden. The net effect of this architecture is higher speed, better over all performance, and unequaled cost efficiency. Specific examples of how this FEP technology yields these benefits are:

TELNET Connections

In a typical environment, users employ the TELNET protocol to access applications running on the host. As the user types on his keyboard, each character travels over the network to the host causing an interrupt. TCP/Link's FEP software assembles these individual characters into a complete line of input, causing only one host interrupt.

6530 Applications

The 6530 terminal is supported by an ACK/NAK protocol which limits the size of any individual I/O to or from the terminal. When in block mode, every screen of data sent to the terminal must be broken up into smaller blocks, each of which must be individually acknowledged by the 6530. Host based implementations of TCP/IP must perform an individual I/O for each of these protocol events. The TCP/Link FEP implements this protocol entirely, relieving the host of all of this communications related overhead since only one host I/O must be performed.

File Transfer Applications

Due to the Ethernet packet size limitation of only 1,460 bytes of data, files that are transferred over the TCP/IP network must be broken up into individual packets by the sending system and then reassembled by the receiving system. Host based implementations of TCP/IP must perform all of this work in the host itself, causing an I/O for each and every individual packet. TCP/Link instead moves very large blocks of data to the FEP which performs all of this work on behalf of the host, relieving it of huge amounts of communications overhead and expense.

Further Details

To learn more about FEP architecture, its implementation, and its advantages, follow any of these links:

• "Achieving High Performance TCP/IP On Your Tandem System" is a downloadable document describing the details of FEP architecture advantages.
• Frequently Asked Questions (FAQS) may answer some of your remaining questions.
• An on site product demonstration is the best way to get into the "nuts and bolts" of any product .
• Contact a Failsafe representative to discuss product capabilities.