[PACKET SWITCHING] Possibly Useful Protocol Software
I have made a software release
(http://www.softlane.com/downloads1-0.html) that may be of interest to
some of the subscribers to this list.
I occasionally teach a course at Harvard in Understanding and
Implementing High Performance Packet Switching Systems. In my course,
I argue that the development trend in this field is much too much
oriented toward developing hardware. Concentration on hardware
development rather than developing correct software approaches leads
to premature obsolescence of equipment, inadequate performance or
bottlenecks and tremendous maintenance or development costs.
Overemphasis on hardware packet switching technology may actually slow
the development of Internet technology as a whole.
In order to make this point, I have decided to release some of the
course material under non-commercial licenses. I am first releasing
Solaris LAPB drivers. Now I know that many people consider X.25, LAPB
and SDLC rather despicable technology, but correctly implemented X.25,
LAPB or SDLC can provide very good link utilization in the presence of
noise or when using large numbers of earth-satellite links. Moreover,
the best engineers have a good grasp of the historical developments in
their fields. The famous Tacoma Narrows bridge collapse would not
have happened if the American civil engineers involved in the design
had had a better knowledge and understanding of 19th century European
bridge design. With regard to operating system design, it used to be
proverbial that those who did not know Multics were doomed to recreate
it. Unfortunately, nowadays few people have even heard of Multics.
X.25, LAPB and SDLC are particularly relevant today because a lot of
the developments associated with these technologies have direct
relevance to VOIP.
I am making this announcement on the following mailing lists:
list@... (because ISPs should be interested in better
packet switching software),
cisco@... (because I occasionally see interest in
building LAPB and HDLC interfaces for Solaris to talk some forms of
IP/LAPB or IP/HDLC specific to Cisco -- I am interested in extending
these drivers to perform such communications but would need to work
with someone with up-to-date Cisco routers),
OSPF@... (a list interested in software aspects of
gated-people@... (another list interested in software aspects of
linux-router@... (yet another list interested in software
aspects of packet switching -- I might develop Linux versions of these
drivers if there is interest),
packet-switching@... (my own mailing list dedicated to
understanding and implementing high performance packet switching
tcpsat@... (the technology of LAPB and SDLC satellite links
has a lot of relevance to the mailing list).
The drivers provided have been tested extensively on Aurora
Technologies, Inc. (http://www.auroratech.com) synchronous serial
cards (SBUS 401S+ [4 port], SBUS 800S+ [8 port], PCI 4520 [4 port],
PCI 8520 [8 port]). The demands made on the synchronous serial
adapter card are minimal (example programs are included), and there is
great likelihood that the drivers will work with other synchronous
Supporting networking software is very expensive and often requires
expensive analytic tools. I cannot warrant the implementation even
though I believe it is excellent.