swb@TCGOULD.TN.CORNELL.EDU (Scott Brim) (12/11/87)
We would like to add DECNet support to our p4200s, but are really concerned about memory. We estimate that if we have both IP and DECNet we will only have about 80 buffers left in the best case. Are my fears justified? Thanks ... Scott
jnc@BRUBECK.PROTEON.COM (12/11/87)
Scott, as far as I know, 80 buffers should be plenty (unless you have 8 network interfaces or so :-). Remeber, buffers are only useful to smooth out peaks in the traffic; lots of buffers are actually *worse* than a few buffers. (There's at least one RFC that explains why; it's by John Nagle. Basically, when you congest, more buffers means more old packets heanging around. Lots of buffers do not help stuff 2 MB/sec down a 1 MB/sec channel!) Look at the gateways now and see what the avergae number of buffers in use is when they are running, and subtract that number from 80; if the resulting number is much larger than 20 or so you should be OK. Also, remember that because of the DECNet algorithms, setting parameters substantially larger than they need to be uses memory. I'm not too familiar with DECNet, but customer service has had a lot of experience in this area and can fill you in on all the bits. Noel -------
medin@ORVILLE.NAS.NASA.GOV (Milo S. Medin, NASA ARC Code ED) (12/12/87)
You need 1 MB of RAM if you want to run DECNET (on 7.4) and are connected to a large DECNET. Thanks, Milo