Shmuel, If this were clearly documented anywhere I could come down somewhat harder on those who propagate these supposedly qualified descriptions of the PU entity.
Maybe I can demonstrate in a negative way. Searching for 2.1 in the SNA Formats manual gives 4 hits. The first, strangely enough, is in the description of ACTPU and refers to the Format 1 ACTPU being used only by a type 2.1 node which indicates in the format 3 XID that the "PU Capabilities" vector may be present. The second is actually quite helpful. It is in 6.1, "Introduction to Request Units", point 8: <quote> A type 2.1 (T2.1) node contains a control point (CP) rather than a physical unit (PU). However, it can support SSCP-PU T2.0 flows, in which case the designations "SSCP -> PU T2" or "SSCP -> PU" in the RU descriptions should be assumed to apply to the T2.1 node as well. </quote> I can't really explain the third hit but the 2.1 refers neither to a PU nor a node. The fourth hit is a section reference. Since the helpful second hit mentioned that "type 2.1" is abbreviated as "T2.1", I checked hits using "T2.1" also. The 9 hits here were all for T2.1 nodes (except one where the entity is a "link station" rather than a "node"). I think the text you found logically, if not chronologically, precedes the introduction of the type 2.1 node and the introduction of the "control point" as the entity managing the node rather than always the PU. (I know, if you look hard enough you'll be able to find references to an SNA entity called the PU control point, PUCP.) In the simple days of pure subarea networking, there was the type 5 node with its SSCP and type 5 PU (VTAM), the type 4 node with its type 4 PU (NCP) and the type 2 node with its type 2 PU (all the peripheral nodes except a few rather basic ones). The basic nodes were type 1 nodes with a type 1 PU which, oddly enough, stayed within the NCP. Also whenever NCP needed to provide a home for an internal LU, the structure of a type 1 node was built internally as, for example, with the NTO "add-on" product. Chris Mason ----- Original Message ----- From: "Shmuel Metz (Seymour J.)" <[EMAIL PROTECTED]> Newsgroups: bit.listserv.ibm-main To: <[email protected]> Sent: Sunday, 23 April, 2006 2:36 PM Subject: Re: Need Help defining an AS400 with an IP address to the mainframe > In <[EMAIL PROTECTED]>, on 04/22/2006 > at 07:02 PM, Chris Mason <[EMAIL PROTECTED]> said: > > >[5] A PU is always type 2. There is no qualification possible for the > >"2". There are masses of misleading instances of the horrible term PU > >2.1 - it hurts my fingers to type it - out there, some of it > >shamefully at the hands of VTAM developers who know they know better > >- just try asking one. The only trivial excuse is that "PU' takes up > >less space than "node". In other words, it's "node" that can be > >qualified as type 2.0 or type 2.1, not "PU". > > Do you have documentation for that/ While admittedly old, my copy of > Format and Protocol Reference Manual claims that it is the PU that has > a type designation and that "type i node" is an alias for "PU_Ti node" > > -- > Shmuel (Seymour J.) Metz, SysProg and JOAT > ISO position; see <http://patriot.net/~shmuel/resume/brief.html> > We don't care. We don't have to care, we're Congress. > (S877: The Shut up and Eat Your spam act of 2003) ---------------------------------------------------------------------- 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
