ps@diab.UUCP (06/03/87)
We are looking for a software package that implements the OSI-model protocol levels 3(internet), 4(transport class 0,2,4), and 5(session) in whole or parts. The software need not be a commercial product, or even completely functional. If suitable, it will be a base for further development. It is a requirement that the software could become the property of this company (no licensing), on a non-exclusive basis with no restrictions on it's future use or distribution. Any hints are appreciated. Thanks in advance. -- Per-Erik Sundberg, Diab Data AB SNAIL: Box 2029, S-183 02 Taby, Sweden ANALOG: +46 8-7680660 UUCP: seismo!mcvax!enea!diab!ps
mac@idacrd.UUCP (06/04/87)
in article <223@diab.UUCP>, ps@diab.UUCP (Per-Erik Sundberg) says: > Xref: idacrd comp.dcom.lans:459 comp.protocols.misc:22 comp.sources.wanted:1227 > > > > We are looking for a software package that implements the OSI-model > protocol levels 3(internet), 4(transport class 0,2,4), and 5(session) > in whole or parts. The software need not be a commercial product, or > even completely functional. If suitable, it will be a base for further > development. It is a requirement that the software could become the property > of this company (no licensing), on a non-exclusive basis with no restrictions > on it's future use or distribution. > > Any hints are appreciated. Thanks in advance. > AHHHAAAA Ahhhaaa hahahahahaha ahhhhh hahahahahaha ahhh hahahaha Chuckle chuckle etc. Bob
dpz@aramis.rutgers.edu.UUCP (06/04/87)
>From: mac@idacrd.UUCP (Bob McGwier) >>We are looking for a software package that implements the OSI-model >>protocol levels 3(internet), 4(transport class 0,2,4), and 5(session) > AHHHAAAA Ahhhaaa hahahahahaha ahhhhh hahahahahaha ahhh hahahaha > > Chuckle chuckle etc. Pretty friggin obnoxious. Go play with your toys, unless you have an intelligent answer for him. dpz -- David P. Zimmerman rutgers!dpz dpz@rutgers.edu
steckel@alliant.UUCP (06/05/87)
Anyone contemplating using OSI protocols should read Padlipsky's comments in the tcp-ip mailgroup (comp.dcom.tcp-ip I think). He exposes far better than I can the fundamental flaws in network protocols prescribed by PTTs (national postal/telegraph/telephone monopolies) or other monolithic entities. He has also published a book on the subject - suitable for making implementors cry and standards committee members break out in flames. (Sorry, I can't remember the title but I could find out if enough interest) OSI doesn't tell you how to make a network. It only tells you how to (supposedly) connect to a (supposedly perfect) network. All OSI protocols fall extremely short on error handling. Even X.25, the closest to usable of all the OSI protocols, has had several revisions because of this problem and it's a low level! Read Padlipsky and weep (or break into hysterical laughter!). geoff steckel (steckel@alliant.uucp, gwes@wjh12.uucp)
jmg@cernvax.UUCP (jmg) (06/05/87)
In article <233@idacrd.UUCP> mac@idacrd.UUCP (Bob McGwier) writes: >in article <223@diab.UUCP>, ps@diab.UUCP (Per-Erik Sundberg) says: >> We are looking for a software package that implements the OSI-model >> protocol levels 3(internet), 4(transport class 0,2,4), and 5(session) etc. >> Any hints are appreciated. Thanks in advance. > >AHHHAAAA Ahhhaaa hahahahahaha ahhhhh hahahahahaha ahhh hahahaha > >Chuckle chuckle etc. > >Bob > May I say that this is the sort of inane reply which drives me wild. It has no information in it, other than an implied snide comment. Personally, I would prefer that Mr. McGwier thinks for a few microseconds before issuing such a reply. As it happens:- 1. I already sent off four names to the original sender, and there are certainly more. 2. We are currently running (and interworking with) three different ISO TP4 implementations (on Vax, 68000 and IBM PC). 3. The sender is not English mother tongue (although he speaks it probably rather better than most readers speak his language), and so is possibly upset by the answer.
nrh@chuck.bellcore.com.UUCP (06/06/87)
In article <526@alliant.UUCP> steckel@alliant.UUCP (Geoff Steckel) writes: >Anyone contemplating using OSI protocols should read Padlipsky's comments >in the tcp-ip mailgroup (comp.dcom.tcp-ip I think). He exposes far better >than I can the fundamental flaws in network protocols prescribed by PTTs >(national postal/telegraph/telephone monopolies) or other monolithic entities. >He has also published a book on the subject - suitable for making implementors >cry and standards committee members break out in flames. (Sorry, I can't >remember the title but I could find out if enough interest) >... >Read Padlipsky and weep (or break into hysterical laughter!). > geoff steckel (steckel@alliant.uucp, gwes@wjh12.uucp) Padilipsky's book is called "The Elements of Networking Style", and is published by Prentice-Hall.
fair@ucbarpa.Berkeley.EDU.UUCP (06/07/87)
Followup-To: I wish to echo the recommendation of Michael Padlipsky's book, which is The Elements of Networking Style and other Essays & Animadversions on the Art of Intercomputer Networking Michael A. Padlipsky published by Prentice-Hall, 1985 ISBN 0-13-268111-0 01 It is most frustrating to only be able to sit idly by while most of the computer industry gives lip service to ISO vaporware, while a superior, second generation protocol suite goes mostly ignored (unless the customers have the sense to ask for it): DoD IP/TCP. Erik E. Fair ucbvax!fair fair@ucbarpa.berkeley.edu
mel1@houxa.UUCP (06/07/87)
In article <19265@ucbvax.BERKELEY.EDU>, fair@ucbarpa.Berkeley.EDU (Erik E. Fair) writes: > It is most frustrating to only be able to sit idly by while most of the > computer industry gives lip service to ISO vaporware, while a superior, > second generation protocol suite goes mostly ignored (unless the > customers have the sense to ask for it): DoD IP/TCP. I am new to the field of networking and am getting very confused. I see lots of utility in the TCP/IP offerings and uses. I was a user of the ARPANET for many many years (without the slightest knowledge about what was providing such great services). I use an Ethernet in our lab that connects dozens of systems from different venders and opertaing systems. Both work very reliably, relatively fast, and duck simple to use. What does ISO offer that TCP/IP doesn't? Is it significantly faster? I can't think of any other measure that needs improving. Is there a war going on? TCP/IP vs ISO? Who is on which side? Why? Mel Haas , odyssey!mel
ast@cs.vu.nl (Andy Tanenbaum) (06/09/87)
In article <492@houxa.UUCP> mel1@houxa.UUCP (M.HAAS) writes: >What does ISO offer that TCP/IP doesn't? Is it significantly faster? >I can't think of any other measure that needs improving. > >Is there a war going on? TCP/IP vs ISO? Who is on which side? Why? The ISO OSI model is an attempt to provide a framework for networking from the physical bit transport to the applications. The model itself does not contain protocols at all, although ISO has standardized some protocols and services for the various layers. TCP and IP are two specific protocols for layers 4 and 3, respectively, and as such can be used to fill two of the slots in the OSI reference model. Other protocols are needed for the other layers. Virtually everyone now agrees that the OSI model is a good way to look at networking. The war is about which protocols which be used in which layer. TCP is clearly one candidate for the transport protocol, but most companies in the U.S., and virtually all companies outside the U.S. are committed to supporting the ISO OSI transport protocol and the ISO protocols in layers 5 through 7 too. (1-3 are much fuzzier, what with IEEE 802 etc.) There has been a lot of generalized disgust with OSI expressed here and elsewhere. I would be very interested in hearing specific comments about 1. What is wrong with the OSI model itself. 2. What is wrong with the specific protocols ISO has adopted. Comments like: you can't go out and buy it off the shelf right now don't count. If the standards people waited until every company had already had a running network product, they would all be different and there would be no standard at all. The only way to achieve standardization in this area is to agree on the standards before every company invests a lot of money doing it some nonstandard way. Thus it is not surprising that the standards are here before all the implementations. Nevertheless, there are certainly plenty of valid criticisms of the model and the protocols (e.g., the session layer is pointless, the presentation layer is practically empty, they forgot about encryption altogether etc.). I would like to see a discussion of this subject, preferably by people who know what they are talking about. Andy Tanenbaum (ast@cs.vu.nl)
karn@faline.UUCP (06/13/87)
In article <1204@botter.cs.vu.nl>, ast@botter.UUCP writes: > Virtually everyone now agrees that the OSI model is a good way to look at > networking. The war is about which protocols which be used in which layer. About the only thing virtually everybody agrees on is that hierarchical layering is usually a good idea in a computer communication network. The ISO Reference Model (not so fondly called "eyesore-emm" by Padlipsky) is only one of several possible hierarchical models, and a rather outdated one at that. Among the major flaws of the ISO Reference Model are: 1. A fixed number (7) of layers. In a real network there may well be more or less than 7 layers. The important thing is the relative position of a protocol in the hierarchy and the function it performs, not the fixed "level x" designator it might have. Jon Postel and Danny Cohen wrote a paper a few years ago in which they examined some real networking systems and showed that either a) N = N + 1 (for any value of N), OR b) the notion of "seven and only seven layers" is fundamentally flawed. 2. It completely ignores internetworking. This is related to point #1, since in a real internetwork you may very well have two or more network layers in a "stack", e.g., a subnet layer underneath an internet layer. (Some people do split ISO Layer 3 into Layer 3A, the Subnet layer, and Layer 3B, the Internet layer.) The fact that the model still doesn't formally recognize the very real existence of and need for internetworking says something about the motivations of those who influence the ISO. 3. Overly redundant layer functionality. My pet peeve is the use of the term "reliable" in the link layer description, implying that the primary burden for reliable delivery of information rests here instead of the transport layer where it belongs. No other concept has contributed so much to needless complexity, inflated costs and lousy performance than the stubborn notion that each and every layer must "guarantee" reliability, usually through the use of an overhead-laden connection- oriented protocol. A decade ago this mentality brought you X.25. Now it has resurfaced in an even more astonishingly byzantine creation, "IEEE 802.1 Connection- Oriented Logical Link Control" (basically X.25 over Ethernet, believe it or not). For more on the general subject of end-to-end vs low level reliability mechanisms, see "End-to-end Arguments in System Design" by Jerome Saltzer of MIT. 4. While important concepts are ignored, another layer exists whose function is questionable at best: the Session layer. I've yet to figure out just what it's supposed to do, and why a separate layer is needed to do it. 5. While not a fault of the ISO RM per se, some of its overly zealous followers (whom Padlipsky also not-so-fondly refers to as ISORMites, pronounced "eyesore mites") tout it as *the* way a network *must* be built. Even the originators of the ISORM never intended it as anything other than as a general guide to *naming* the pieces of *existing* networks. For example, I've had people tell me that I can't have a "network" without a separate Session layer, even though TCP and UDP have perfectly adequate port numbering and "well known socket" mechanisms. When I ask why, they say "ISO says so". In addition to the faults of the underlying reference model, the ISO/OSI "protocol suite" has a host of faults of its own. First and foremost among them is the fetish for connection-oriented protocols. Only recently did a connectionless transport protocol get added, despite the widespread use of UDP in the ARPA Internet for things like network databases and distributed file systems. On the other hand, there are a FIVE different and mutually incompatible protocols all providing a connection-oriented transport service (TP-0 thru TP-4). If the ISO was *really* serious about "open systems interconnection", they would pick ONE connection-oriented transport protocol (TP-4, the most general one). They claim you don't need all that reliability if you're running on a PTT network, but of course the real reason is that they're scared to death of internetworking. There's no way a PTT is going to allow it to happen unimpeded. Yes, eventually you may be able to pick a "subset" of the ISO stack that answers the needs of the internetworking world. But if you do, you end up with something that is similar to, but (deliberately) incompatible with TCP/IP. So why bother? In summary, if you think open systems interconnection is a good idea, I agree. That's why I and so many others use TCP/IP. I have nothing against migrating to an international standard if it is provably superior to what we have (e.g., the metric system vs the English system) but this is *not* the case with OSI in its present form. I also dislike the "bomb crazed military", but I also see no reason not to take their technology and beat it into plowshares. In fact, it gives me a real feeling of satisfaction to take military technology and pervert and subvert it to peaceful uses! Phil
kre@munnari.UUCP (06/20/87)
In article <638@faline.bellcore.com>, karn@faline.UUCP writes: > Among the major flaws of the ISO Reference Model are: > > 1. A fixed number (7) of layers. These are just conceptual layers, and they don't (and aren't mean to) include layers in application processes. You can recursively redefine any of those layers as much as you like for whatever purposes are appropriate (eg: level 2 on lans has llc and mac, but its all still level 2 .. point to point). > 2. It completely ignores internetworking. This is rubbish. > They claim you don't need all that reliability [TP4] if you're running on a > PTT network, but of course the real reason is that they're scared to > death of internetworking. There's no way a PTT is going to allow it to > happen unimpeded. I think your arguments about PTT fears need a little examination. Most of the world's PTT's don't need standards to control the world's networking (this is outside the US). In most countries the PTT's have a legal monopoly, they don't need this kind of extra second hand pseudo-protection. I have no love for PTT's and their regulations, however before discounting all their arguments, its worth placing yourself in their position for a while. Let's indulge in a little whimsy. Imagine yourself offered the job of director general (or whatever its called) of the arpanet (and nsfnet, span, csnet, etc for fun). You're naturally overjoyed, as quite apart from the 6 (or perhaps 7) figure salary, you're finally going to be able to stamp out all this OSI nonsense on the arpanet, and get things finally back on the straight and narrow of TCP/IP. So far, so good, everything's running smoothly, until one day there's a rash of "hacker" breakins at military institutions doing weapons research, and evidence is that this comes from the educational (research) side of the net .. the part you are in control of. Big stink in the press, congressmen up in arms, the lot. Of course, no-one suggests that OSI would have been any better (that's not my point). But, finally someone raises a question... the US goverment (the taxpayer) is paying for these hackers to wreak havoc on the US national security, Why? This must be stopped at once. In one of those amazing happenings in the US congress and Senate a bill is passed, and receives Presidential assent, all within a day. It denies any goverment funding to the networks. Not only direct funding, but indirect funding through research grants, contracts, etc, and denies tax deductions for gifts to any organizations that use any of the gift for networking purposes. Congress is really mad! Now, you have something of a problem. Here you are in charge of this network that has no money, and the bills are starting to come due. How are you going to solve this problem? You can try and get people to donate funds out of the goodness of their hearts, but somehow I doubt that is going to work. You're likely to have to reach the position where you have to actually charge real money to the people who use your networks. You're more or less in the position of the PTT's in the rest of the world, you're running a business, and you have to at least break even, if not make a profit, or your network collapses. It might be instructive to explain how, with the current internet setup, and using the standard IP based protocols (which of course you have the authority to change if you want) you are going to make all this work. Nb: I mean the whole internet here, including all those sites that have slip, and csnet x.25, links to the lucky few on net 10. > I have nothing > against migrating to an international standard if it is provably > superior to what we have (e.g., the metric system vs the English system) > but this is *not* the case with OSI in its present form. You're right, OSI is not ready for use yet, it needs some more work (though many of the individual protocols are perfectly ok). But asking for it to be provably superior is asking too much. It might never achieve that in the sense you mean. What it will be is demonstrably more widely available. That is, one day you will be able to connect to us (in Australia) using OSI. Chances are you never will be using TCP. Which is strange, as we run TCP now, so do you. Neither of us runs OSI... (But the US government won't allow us to connect to you using TCP, we would have to get some special dispensation to allow packets from outside the US onto the arpanet, and that's simply not worth bothering with). We could set up some direct TCP link (possibly over an X.25 carrier..., it would certainly be over some PTT carrier, as that's all that's available) but then you would have to take special precautions to make sure none of our packets escape. What great internetworking! Remember that continually bemoaning the lack of readiness of the ISO protocols does nothing to help them get completed. You'd be better assisting ISO, I know that you have lots of TCP knowledge, you must have plenty of experience that would be quite valuable, and perhaps you could be helping to prevent some of the mistakes that you see ISO making, instead of just complaining about them. kre ps: Phil .. mail to you on the backbone list is being addressed to bellcore!bellcore.com!karn (or something similar) and is making bellcore's mailer dump core (SIGSEGV), you might want to look into that.