schoff@rpics.UUCP (Martin Lee Schoffstall) (11/11/85)
I'm interested in leasing a DDS (56kbit) line across NY State to connect two LAN's. The cheapest path (hardware wise) seems to be buying a DMC11. There are about 8 different types of DMC11's available..... a couple of the more noteworthy ones include: DMC11-DA Remote Line Unit v.24 DMC11-FA Remote Line Unit v.35 A pair of 4.2bsd machines would be the "gateways". Obviously there would be a DSU involved. I would like to hear from anyone who has had experience with this. thanks, -- marty schoffstall schoff%rpics.csnet@csnet-relay ARPA schoff@rpics CSNET seismo!rpics!schoff UUCP martin_schoffstall@TROY.NY.USA.NA.EARTH.SOL UNIVERSENET RPI Computer Science Department Troy, NY 12180 (518) 271-2654
ron@BRL.ARPA (Ron Natalie) (11/12/85)
Actually, the new ACC communications board for UNIBUS may be cheaper than the DMC (or DMR). It certainly is smaller. -Ron
jbn@wdl1.UUCP (11/13/85)
1. Both DMCs and DMRs have many problems, but can be made to work.
Gory details available on request.
2. Local/long haul networking with mixed fast/slow links doesn't
work in 4.2 very well; it does work in 4.3. Problem areas:
- DMR driver supplied with 4.2 is a disaster. Many fixes needed.
See Mt. Xinu buglist.
- The code needed to specify the address for the other end of the
point to point link is missing from 4.2; several people have
posted fixes recently. Incidentally, the Mt. Xinu NFS code
breaks this if previously fixed; get the very latest (this week)
Mt. Xinu fixes for this if you get support from them and need it.
- There are serious congestion problems in 4.2BSD's TCP. Don't
expect much of TELNET when slow links are involved; every key
stroke sends 41 bytes down the line. Worse, the retransmit
timer is too short in stock 4.2BSD. Both bugs are fixed in 4.3.
- Network management support is lacking; link errors are not
tallied and logged for line trouble evaluation; packets dropped
due to overload are not logged, and network loading statistics
are not collected in any useful way.
We still run 4.1BSD with UNET networking ourselves, pending official
release of 4.3 or local generation of enough fixes to make this work well.
John Nagle