channel 2.1 protocol

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2 total messages Started by Mark Roddy Sat, 01 Jun 1991 21:07

#1030

Author: Mark Roddy
Date: Sat, 01 Jun 1991 21:07

24 lines
1195 bytes

Okay, I give up. Is there an IBM publication, formal or otherwise,
that actually defines the PU2.1 <- (NOT PU2.0!!!) local channel
protocol, including ___XID___ negotiation?

I have enough references, mostly contradictory, that such a protocol
exists and that it is different from the PU2.0 (AKA 3274-1a) protocol.

Please mail me a clue.


And while we are on the subject. The IBM publication "Type 2.1 Node
Reference" rather clearly states that all 2.1 nodes support XID
format three (3) while the IBM publication "Network Product Formats"
rather clearly states that a channel 2.1 link uses XID format two (2).
(But then again consistency is the hallmark of little minds.)




-- 
-Mark Roddy
Sequoia Systems, Inc.          (508) 480-0800 x1284
markr@seqp4.sequoia.com        m2c!seqp4!markr

Re: channel 2.1 protocol

#1033

Author: David Skeen
Date: Tue, 04 Jun 1991 01:05

23 lines
1876 bytes

Between the Type 2.1 Node Reference and Network Product Formats, you
probably have all the available info for type 2.1 local channel
protocol.  In general, type 2.1 nodes "discover" each other by XID3
exchange.  VTAM system definition for the PU will say "TYPE=2,XID=YES". 
VTAM will send a null XID; if it sees in response XID0 or XID1, it
assumes the node is type 2.0; if it sees in response null XID or XID3,
it assumes the node is type 2.1.

>                        the IBM publication "Network Product Formats"
> rather clearly states that a channel 2.1 link uses XID format two (2).

I don't see this in my June '89 copy.  If you look near the end of the
description of XID3, you'll see that there are two DLC-dependent
sections defined--one for SDLC (also used for Token Ring and X.25), the
other for Channel DLC.  My copy says this CDLC section is for
communication "between T4 and T2.1 nodes", but that's not terribly
accurate.  In fact, when NCP or VTAM communicates with a T2.1 node, they
assume the identity of a T2.1 node.  There is no T4-T2.1 nor T5-T2.1
protocol defined, only T2.1-T2.1.
--
Dave Skeen                     IBM Internal: dls@achilleus.austin.ibm.com
D61/803  Zip 2603              IBM VNET:     SKEEN at AUSTIN
Austin, TX 78758               Internet:     dls@dce.austin.ibm.com

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