RFC 2043 (rfc2043) - Page 5 of 7
The PPP SNA Control Protocol (SNACP)
Alternative Format: Original Text Document
RFC 2043 PPP SNACP October 1996 Configuration Option Types There are no Configuration Options for SNA or for SNA over LLC 802.2. 3. Sending SNA PIUs and NLPs. Before any SNA packets may be communicated, PPP must reach the Network-Layer Protocol phase, and the appropriate SNA Control Protocol must reach the Opened state. The maximum length of a SNA packet transmitted over a PPP link is the same as the maximum length of the Information field of a PPP encapsulated packet. The format of the PPP Information field itself is the same as that defined in [1]. Detailed information on SNA and APPN can be found in [3], [4], [5], [6], and [7]. 3.1. Sending SNA XID or FID2 PIUs over LLC Exactly one SNA XID or FID2 PIU over LLC 802.2 is encapsulated in the PPP Information field, where the PPP Protocol field indicates type hex 004B (SNA over LLC 802.2). A summary of this frame structure, beginning with the PPP Protocol field, is shown below. The fields are transmitted from left to right. -- LLC portion (PPP Information Field) ------------- | | -+----------+----------+----------+----------+-------------------+- | Protocol | DSAP | SSAP | Control | LLC Information | | 0x004B | Address | Address | Field | Field | -+----------+----------+----------+----------+-------------------+- The LLC information field contains the XID or FID2 PIU. LLC(2) is included in this format for link-level error recovery. Error recovery is done by the routers at each end of the PPP link. 3.2. Sending HPR Network Layer Packets (NLPs) Exactly one HPR Network Layer Packet (NLP) is encapsulated in the PPP Information field, where the PPP Protocol field indicates type hex 004D (SNA). Fuqua Standards Track
