DOCUMENT:Q149444 13-JUN-2001 [sna] TITLE :Downstream PU to DEC Server May Fail with Event 56: XID Reject PRODUCT :Microsoft SNA Server PROD/VER:WINDOWS:2.0,2.1,2.11,3.0 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft SNA Server, versions 2.0, 2.1, 2.11, 3.0, on platform(s): - the operating system: Microsoft Windows NT ------------------------------------------------------------------------------- SYMPTOMS ======== When you try to configure Microsoft SNA server as a Downstream Physical Unit (DSPU) to an DEC SNA Peer Server, you may get an XID exchange failure resulting in the link entering a pending state and failing to activate. The Microsoft Windows NT application event log may contain an EventID 56 with the following description referencing xxxxx as the failing connection: Connection xxxxx failed: XID rejected by remote computer. Further investigation using the SNA tracing utility may demonstrate an XID exchange failure in CONNECTx.TRC with the following sense code: 086F0000:- Length Error: A length field within an MS major vector is invalid, or two or more length fields are incompatible. CAUSE ===== There is an error in the XID3 transmitted by SNA Server version 2.11 that prevents it communicating over 802.2 DLC with some SNA PU 2.1 products that specifically validate the control vector in the XID. The Control Vector part of the XID (byte 29 onwards for SDLC) is incorrectly formatted. The first part of the Product Set ID (X'10') Control Vector is a Product Identifier (X'11') MS Common Subvector of Product classification X'0C'. This subvector has an indicated length field of X'27'; however, it is only X'23' bytes long. Attached is an extract from a trace (connect1.trc) of an XID exchange with a Digital SNA Peer Server. The Control Vectors start at byte 29 with '10370=3D0'(Product Set Id). The next three bytes '27110C' indicate a 0x27hex length (39 decimal) byte Product Identifier Subvector. In fact this subvector is only 0x23 hex (35 decimal) byte length: 3 byte header, X'27110C' 8 byte Software Product Common Level '021000', 15 byte Software Common Product Name 'MS SNA SERVER' 9 byte Software Product Program Number '0000000' The trace continues with an XID rejection from the DEC Peer Server with the following sense data: '086F0000' "Length Error: A length field within an MS major vector is invalid, or two or more length fields are incompatible. The significant portion of Connect1.trc obtained by enabling Level 2 tracing on the link service follows: ---------------------------------------------- 15:07:24.61 TR XMIT XID CMD REQUEST TR ---- DLC API control block at address 73618---- TR 000E0000 00000000 00000000 34360700 <............46..> TR 70000000 00000000 00001C00