AAD@GOLD.SCRIBE.COM (02/17/88)
I was once told that the lat servers send an ethernet packet for every character, and that thus the overhead is ~256 to 1. (The same person said that the minimun size for an enet packet is something like 256 bytes)
hildum@iris.ucdavis.edu (Eric Hildum) (02/25/88)
In article <8802210603.AA29392@ucbvax.Berkeley.EDU> AAD@GOLD.SCRIBE.COM writes: > >I was once told that the lat servers send an ethernet packet for every >character, and that thus the overhead is ~256 to 1. (The same person >said that the minimun size for an enet packet is something like 256 bytes) There is a little more to the LAT server's algorithm than this. The server will wait a set amount of time, hoping that others will also type something in, before sending the packet. This time is picked so that the induced delay in response will not be noticeable to the users. The optimization is for a maximum delay, rather than a shortest average delay. The article "Terminal Servers on Ethernet Local Area Networks" in the Digital Technical Journal #3, September, 1986 goes into this in more detail. Eric dehildum@ucdavis.ucdavis.edu (Internet) dehildum@ucdavis.bitnet (BITNET) ucbvax!ucdavis!dehildum (uucp)
dave@wsccs.UUCP (Dave E Martin "VAX Headroom") (03/02/88)
In article <8802210603.AA29392@ucbvax.Berkeley.EDU>, AAD@GOLD.SCRIBE.COM writes: > > I was once told that the lat servers send an ethernet packet for every > character, and that thus the overhead is ~256 to 1. (The same person > said that the minimun size for an enet packet is something like 256 bytes) Lat servers have a timeout value, usually 80 milliseconds on decservers. During this time they collect characters on all terminals and buffer them up. After the timeout has expired, they will send ALL collected characters as one ethernet packet (unless, of course they total more than the maximum packet size). I believe the minimum ethernet packet size is aprox. 43 bytes. +-----------------------------------------------------------------------------+ | | Dave E Martin | DISCLAIMER: Been Cancelled | | /\ | "...between the streets of | $ opinion/mine/noUinTech | | / \ . /\ | Dallas, and the beaches of |----------------------------| | / \/ \/\/ \ | Miami ... THIS was Max | ...!ihnp4!utah-cs!utah-gr! | | / U i n T e c h \ | Headroom's finest hour." | uplherc!sp7040!obie! | | | --Max Headroom | wsccs!net23.dnet!dave | +-----------------------------------------------------------------------------+