west%etd1.DECnet@AFWAL-AAA.ARPA ("ETD1::WEST") (11/12/87)
At the Air FDorce Avionics Lab, we have an Ethernet backbone with (at least) 12 VAX and lots of graphics workstations attached. This backbone runs DECnet, LAT, CALMAnet, TCP/IP and more. This backbone serves AT LEAST 40 and maybe more highly utilized terminal servers (DECserver 100 and 200's.) This is 320 terminals and PC's connected by LAT, there are also several (10-15) devices connected by reverse LAT on DS200's...FOM's etc. My point...the net is busy but not strained. There is NO terminal I/O degredation...and this technique beats using DZ-11's hands down for off loading processing. A performance audit showed that 15% of the CPU was being spent handling interrupts (from DZ-11's). After getting rid of the DZ's and going to LAT, the time spent in interrupt was .LT. 2%. Over 10% of the VAX cpu time was returned to the users for the price of an upgrade which is justifiable in terms of convenience (for distributed connect capability) alone! Mike West Air Force Avionics Lab AFWAL/AADE WPAFB, OH 45433 west%etd1.decnet@afwal-aaa.arpa ------
west%etd1.DECnet@AFWAL-AAA.ARPA ("ETD1::WEST") (11/13/87)
At the Air FDorce Avionics Lab, we have an Ethernet backbone with (at least) 12 VAX and lots of graphics workstations attached. This backbone runs DECnet, LAT, CALMAnet, TCP/IP and more. This backbone serves AT LEAST 40 and maybe more highly utilized terminal servers (DECserver 100 and 200's.) This is 320 terminals and PC's connected by LAT, there are also several (10-15) devices connected by reverse LAT on DS200's...FOM's etc. My point...the net is busy but not strained. There is NO terminal I/O degredation...and this technique beats using DZ-11's hands down for off loading processing. A performance audit showed that 15% of the CPU was being spent handling interrupts (from DZ-11's). After getting rid of the DZ's and going to LAT, the time spent in interrupt was .LT. 2%. Over 10% of the VAX cpu time was returned to the users for the price of an upgrade which is justifiable in terms of convenience (for distributed connect capability) alone! Mike West Air Force Avionics Lab AFWAL/AADE WPAFB, OH 45433 west%etd1.decnet@afwal-aaa.arpa ------