jbn@wdl1.UUCP (05/15/84)
Some advice on IP/TCP networks:
1. Trailer encapsulation (a la 4.2BSD) is nonstandard. So is
the use of IP datagrams in excess of 576 bytes. You are only
entitled to use either if you have ``a priori information that
the receiving host is able to accept them''. TOPS-20, for example,
won't.
2. Ethernet address resolution protocol, (Plummer's) is becoming
accepted as the means for finding Ethernet addresses from IP
addresses. Undocumented, but increasingly common, is arranging for
gateways on an Ethernet to answer address resolution polls for
anything they can reach. This means that ARP is all the routing
a host on the Ethernet needs. The case of two gateways on an
Ethernet still presents problems.
3. There are no really satisfactory gateway implementations that one
can buy. There are a number of university-developed gateways, but
no products as yet. We are developing two, but they aren't available
yet.
4. Comments on implementations:
- 3COM's UNET was the first commercial implementation; it
has been withdrawn from the market. We use a much-modified
version of UNET on some of our systems.
- COMPION's implementation for VMS is very slow, especially
for TELNET. Compion isn't very interested in the business,
as far as we can tell; we are an unhappy customer.
- The Wollongong implementation for VMS is a port of the
4.2BSD one for UNIX. It appears to be about as good as
the 4.2BSD, and better than Compion's, but we have not tested
it ourselves.
- DEC's TOPS-20 implementation is buggy and poorly supported.
Plan on investing systems programming time. Contact Mark
Crispin at Stanford (MRC@SCORE) for details and fixes.
- 4.2BSD's implementation is fair; there are known bugs in
retransmit timing and mixed-speed nets have problems with
gateway congestion.
- SUN has the standard 4.2BSD bugs.
- Apollo seems to have done a nice job; we tested UTAH-APOLLO
and didn't find anything wrong, a statement we seldom make.
- Perkin-Elmer still uses UNET.
- Communications Machinery and Excelan have boards which
support Ethernet, IP, and TCP. We haven't tested these
yet.
- Network Research Corporation offers a version of Fusion,
their networking package, which uses IP/TCP. This is
presently available for some M68000 machines, and is
supposedly becoming available for the IBM PC and its clones.mats@dual.UUCP (Mats Wichmann) (05/17/84)
My understanding is that Network Research's Fusion product is XNS
based. They are now advertising TCP/IP as well - I don't know if this
has supplanted the XNS or supplemented it. Does someone know?
Mats Wichmann
Dual Systems Corp.
...{ucbvax,amd70,ihnp4,cbosgd,decwrl,fortune}!dual!matsjoe@fluke.UUCP (05/18/84)
Actually, Compion was recently bought out by Gould, and Gould has "given" the support of the ACCESS software to FlexComm Corp. in Seattle. We just installed V1.8 of ACCESS-I here and although I agree with the comments about speed, it did come up quite easily and fit right into our corporate Ethernet (mainly VAXen and SUNs running 4.2) with no problems at all. One side effect of the shift from Compion to FlexComm is that the FlexComm people are VERY interested in improving the speed of the system. I feel very confident that furture releases of ACCESS from FlexComm will really clean up the implementation and result in a much better product. The address of FlexComm for those interested is: FlexComm Corporation 15245 Pacific Highway South Seattle, WA 98188 (206)243-1641 Maybe I am getting better service since I am a local customer, but I get the impression from talking to them that they would give anyone the same attention long-distance. /Joe