cjdb@ellis.uchicago.edu (Charles Blair) (11/30/90)
I realize I'm in the wrong newsgroup (what's the right one?), but I figured one of you might have the expertise I need, or might be able to point me to it. Simply stated, I am researching the possibility of application to application communication between an IBM-compatible mainframe and a large number of IBM PC's; IBM calls this APPC (advanced program to program communications). I am not interested in any kind of host-to-terminal communications, nor in file transfer protocols. LU 6.2 seems to be the way to go, but I'd like to know what's necessary on the PC end, especially how to implement PU 2.1, which together with LU 6.2 is necessary for APPC. Has anyone developed function libraries for this that I can link in with the applications I'm developing, or do I need to look at cards or "black boxes" of some sort (maybe something that does RS232 on one end, LU 6.2 on the other), or do I need to network the PCs first, with the SNA gateway functioning as the PU 2.1? E-mail responses preferred. If there is a better (or equally good) group for this, please let me know as well. Thanks. -- Bitnet: pmrcjdb@uchimvs1 Internet: cjdb@midway.uchicago.edu
lstowell@pyrnova.pyramid.com (Lon Stowell) (12/05/90)
In article <1990Nov30.021606.19174@midway.uchicago.edu> cjdb@ellis.uchicago.edu (Charles Blair) writes: > >Simply stated, I am researching the possibility of application to >application communication between an IBM-compatible mainframe and a >large number of IBM PC's; IBM calls this APPC (advanced program to >program communications). I am not interested in any kind of >host-to-terminal communications, nor in file transfer protocols. > >LU 6.2 seems to be the way to go, but I'd like to know what's >necessary on the PC end, especially how to implement PU 2.1, which >together with LU 6.2 is necessary for APPC. Has anyone developed >function libraries for this that I can link in with the applications >I'm developing, or do I need to look at cards or "black boxes" of some >sort (maybe something that does RS232 on one end, LU 6.2 on the >other), or do I need to network the PCs first, with the SNA gateway >functioning as the PU 2.1? > Firstly, LU 6.2 does NOT require PU 2.1 or LEN support. You will need PU 2.1 only if you need parallel sessions and Independent LU support...NEITHER of which are recommended for DOS connections to the mainframe....Let VTAM provide the Primary LU function for ALL your sessions..it is much better at this than DOS will ever be. Also do parallel sessions with EXTREME caution, as it is quite easy to create a "deadly embrace" in the non-multitasking environment of DOS....(that info came from the IBM pub... "Advanced Program-to-Program Communication for the IBM Personal Computer: Programming Guide" SX27-3757) You can connect to the IBM mainframe in a variety of ways...your choice will depend on your budget AND the operating system of the PC's.... 1. 3270 Coax. Provides pretty good rates. You put a coax card in the PC and connect it to a 3270 controller. The Host knows you are an LU 6.2 connected via a PU 2.0...and if you are (the 3274) channel attached you will lose a few connectivity options... The "raw" rate is a little over 1 Mbit, but the effective rate is somewhat less... The 3274 or 3174 is itself connected via Channel, Token Ring, or SDLC...in roughly decreasing throughput rates.. 2. SDLC. You will need an SDLC adapter. Spend the extra bucks to get one with a '186 processor on it. You can connect leased or dial directly to the IBM FEP as either a PU 2.0 or PU 2.1 Node...depends on the VTAM/NCP levels in BOTH... Rates vary, bucks gets throughput. 3. Token Ring. You will need a TIC in your FEP...and more memory. Rates are 4 and/or 16 Mbit. You don't really need 16.... Exactly HOW you connect to the Host in this (Token Ring) instance will depend on whose Network Operating System you use... o IBM's OS2/EE provides bundled support for multiple 3270 sessions as well as LU 6.2. DON'T confuse this with Microsoft's OS2 EE which differs considerably.... You don't need a separate gateway for this...the PC's are formal SNA Nodes... (and currently IBM is the ONLY vendor with this native support...) o Several other vendors provide a Gateway solution which connects to the IBM host using SNA over Token Ring, with the rest of the PC's using Netbios to talk to the Gateway... Throughput is lower, but in most instances quite acceptable. Try 3COM, etc... Most of these will work with DOS, MS-DOS, or MS-OS2. The APPC (or LU 6.2) software you buy will influence your choice of connection...some support all of the above, others less... Rabbit, NYNEX-SSI, 3COM, Spectrum Concepts all provide LU 6.2 packages.... Some provide both Mapped and Basic API's, some offer Function Libraries, and some even provide the Service Transaction Programs which can provide a higher level programming interface..... If you get a straight LU 6.2 Mapped and/or Basic API product only, strongly urge getting one with a good API trace capability...you are quite likely to need it... Welcome to Distributed Processing, and Good Luck...
j_rodin@hpfcso.HP.COM (Jon Rodin) (12/06/90)
> o Several other vendors provide a Gateway solution which > connects to the IBM host using SNA over Token Ring, > with the rest of the PC's using Netbios to talk to the > Gateway... Throughput is lower, but in most instances > quite acceptable. Try 3COM, etc... Most of these > will work with DOS, MS-DOS, or MS-OS2. Most vendors of PC SNA emulation products (Attachmate, DCA, etc.) provide direct PC <-> IBM host connectivity via token ring without requiring a gateway. If the PCs are on the token ring there is no reason to stick a gateway in between the PC and the host. Throughput for a tr attached PC is roughly equivalent to a coax attached PC. Jon j_rodin@cnd.hp.com