Radoslaw My intention here was merely to point out that SNA and Ethernet are not equivalent.
In fact, Lee has sent me a private note in which he explains that it was indeed an SNA to IP conversion. The 6400 used to be attached through coax - presumably to a 3270 control unit such as a 3174 I imagine, which was connected onwards using SNA protocols. The 6400 now uses an "AXIS converter" which allows onward transport using IP, Your configuration is still not clear but, as I said, I'm not familiar with all the possibilities. The only configuration I know for a 3270 printer is a VTAM application-VTAM-SNA-3270 control unit-coax-printer - substituting anything which can emulate one of the components. Naturally the VTAM application is using SNA protocols. To offer a proper comparison, the end-to-end flow needs to be clear. But note my first sentence; I'm not necessarily asking for a full explanation. You talk about print servers. I'm very vaguely familiar with the principles of print and file servers as the function appeared in the mid-80's - I think. I recall a young lady explaining these functions based on NetBIOS as they were used by PC software. This was a bit odd since the "network layer" seemed to be missing - or perhaps it was assumed to be catered for by token ring bridging. In any case, you needed to be operating over a LAN end-to-end and the file server application at least assumed LAN speeds I'm equally vague about IPX but I believe that offered similar functions but had a "network layer" where the routing was based on exchange of LAN addresses - or perhaps my memory is defective ... I have never come across SNA-based applications which would allow file sharing and printer sharing. Perhaps there were/are some somewhere. If there were/are, then there would be no basis for your contention that SNA would be "impossible" for such a function as printer sharing possibly designed around a "printer server". Just to be clear, it's the lack of suitable applications not a lack of capability in SNA. In fact, there used to be various AnyNet some protocol over SNA products which included NetBIOS and IPX as the supported "above" protocols.[2] Incidentally, I once had to try to advise on an SNA application that was written on "enabling" software which assumed it was running on a LAN. Once working in a LAN environment it was moved to run over 9,600 bps lines. Probably the impression left was that SNA - even APPN as in this case - was "impossible". I'm not sure at all about your comparison of IP and SNA with regard to ease of routing. When I see the mess that Cisco types get up to in their "forum" to which I subscribe,[1] IP doesn't look so easy after all. If you are comparing IP and *subarea* SNA, you might have a - rickety - leg to stand on. If you are comparing IP and *APPN/HPR* SNA, you'd be left in the dust - from a theoretical standpoint - wildly mixing my linguistic metaphors. <g> Unfortunately APPN/HPR came along too late to save the commercial world from the horrors of IP. Chris Mason [1] I even had the delicious pleasure of posting a response rebutting a claim that "0.0.0.0/0" was strange which consisted of describing the basic IP routing algorithm - in a Cisco forum! [2] Verified in my Multiprotocol Transport Networking presentation ----- Original Message ----- From: "R.S." <[EMAIL PROTECTED]> Newsgroups: bit.listserv.ibm-main To: <[email protected]> Sent: Monday, 15 January, 2007 8:27 AM Subject: Re: 6400 impact printer > Chris Mason wrote: > > Lee > > > > You are talking of an illogical "conversion" here. SNA is a hierarchy of > > protocols which is quite capable of using Ethernet as one of the > > protocols > > in the Data Link Control layer. I guess - only a guess since I don't > > know > > what options exist for a 6400 printer - you mean IP running over > > Ethernet so > > the conversion would be SNA to IP - yet again. > > I used 6400's connected through SNA, the medium was Ethernet. > However I used PC with emulator for printer session, so in fact SNA was > terminated at PC, not printer. It could be impossible to "talk in SNA" > to any regular print server - I doubt if they support SNA. > > BTW: IP over Ethernet seems to be more flexible than SNA over Ethernet. > Although ethernet can be switched and then repeated, IP can be (easily) > routed. > > -- > Radoslaw Skorupka > Lodz, Poland ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
