mann@star.enet.dec.com (Bruce Mann ZK1-3/J35 DTN 381-1298) (01/16/91)
There is a lot of misinformation about LAT. The reason LAT outperforms TELNET (or any other protocol) under a workload where many connections exist between the same two systems is the message rate. The "full protocol stack" issue is a red herring. For instance, with 128 connections active, LAT may be sending about 20-30 packets/second while other protocols send 100s of packets/second. This is because LAT attempts to put all the different session data into a single physical datagram, unlike other protocols. This results in LAT's peculiar timer-based operation and other special policies. LAT has no provision for checksumming - it relies on the underlying LAT 32-bit CRC. Since LAT only operates across LANs, data integrity problems introduced by ISO layers 3-7 reformatting packets (routers/gateways) is not an issue for LAT. Bridges normally forward packets without regenerating CRCs. Bruce Mann LAT inventor