SAP(7)                           Miscellaneous                          SAP(7)

NAME
       sap - Service Access Point specification

DESCRIPTION
       The text2sap and sap2text functions use the format described in this
       man page. Because all standard ATM tools on Linux use those functions
       to convert to or from the textual representation of SAP specifications,
       they expect them in the same format too.

       The SAP is divided into two parts: the broadband high layer information
       (BHLI) and the broadband low layer information (BLLI). A SAP can
       contain one, both, or none of them. In the latter case, the SAP is
       usually considered as a wildcard SAP, i.e. a SAP that is compatible
       with any other SAP.

       Each part begins with its name (bhli or blli), followed by a colon and
       a (non-empty) list of attributes, which are of the form
       attribute=value. Some attributes have sub-attributes, which follow
       them. Everything that isn't separated by a colon or an equal sign is
       separated by a comma.

       Values which are a number of bytes are specified as the corresponding
       sequence of pairs of hex digits. The sequence can be optionally
       prefixed with 0x. Values with are integers in a given range can be
       specified in decimal (no prefix), octal (0 prefix), and hexadecimal (0x
       prefix).

       The following, mutually exclusive attributes are allowed in the bhli
       part (see the corresponding ATM Forum and ITU documents for the
       semantics):

       iso=1-8 bytes
              ISO

       user=1-8 bytes
              User-specific

       hlp=4 bytes
              High layer profile.  Note that this attribute only exists on UNI
              3.0. text2sap only recognizes it if your system is configured to
              accept UNI 3.0 message formats.

       oui=3 bytes,id=4 bytes
              Vendor-specific application identifier

       The structure of the bhli part is more complex. It distinguishes three
       layers, l1, l2, and l3, of which the first one is presently
       unsupported. For layer two, the following (mutually exclusive)
       possibilities exist:

       l2=iso1745
              Basic mode ISO 1745

       l2=q291
              ITU-T Q.291 (Rec. I.441)

       l2=lapb
              Extended LAPB, half-duplex (Rec. T.71)

       l2=iso8802
              LAN LLC (ISO/IEC 8802/2)

       l2=x75 ITU-T X.75, SLP

       l2=x25_ll ...
              ITU-T X.25, link layer. This attribute and the following
              attributes through l2=iso7776 can optionally be followed by one
              or more of the following sub-attributes: mode=mode (mode of
              operation, either norm or ext), and window=window size (window
              size in k, 1-127).

       l2=x25_ml ...
              ITU-T X.25, multilink

       l2=hdlc_arm ...
              HDLC ARM (ISO/IEC 4335)

       l2=hdlc_nrm ...
              HDLC NRM (ISO/IEC 4335)

       l2=hdlc_abm ...
              HDLC ABM (ISO/IEC 4335)

       l2=q992 ...
              ITU-T Q.922

       l2=iso7776 ...
              ISO 7776 DTE-DTE

       l2=user,info=information
              User-specified. information is an integer in the range 0 to 255.

       For layer three, the following (again, mutually exclusive)
       possibilities exist:

       l3=iso8473
              ITU-T X.233 | ISO/IEC 8473

       l3=t70 ITU-T T.70 minimum network layer

       l3=h321
              ITU-T Recommendation H.321

       l3=x25 ...
              ITU-T X.25, packet layer. This attribute and the following
              attributes through l3=x223 can optionally be followed by one or
              more of the following sub-attributes: mode=mode (see above),
              size=default packet size (4-12, corresponding to 16-4096),
              window=window size (see above).

       l3=iso8208 ...
              ISO/IEC 8208

       l3=x223 ...
              ITU-T X.223 | ISO/IEC 8878

       l3=tr9577,ipi=identifier ...
              ISO/IEC TR 9577. identifier is the initial protocol identifier
              in the range 0-255. For SNAP (0x80), the keyword snap can be
              used, and the following sub-attributes have to be specified:
              oui=3 bytes, and pid=2 bytes.

       l2=user,info=information
              User-specified, see above.

       l3=h310 ...
              ITU-T Recommendation H.310. The sub-attribute term=type
              (terminal type, rx, tx, or rxtx) is recognized. If present, it
              enables the two additional sub-attributes fw_mpx=capability
              (forward multiplexing capability, ts, ts_fec, ps, ps_fec, or
              h221) and bw_mpx=capability. Both are optional.

       Note that commas must never follow colons or other commas. Also,
       whitespace is not allowed inside a SAP specification. SAP
       specifications are case-insensitive. On input, items must be written in
       exactly the order used in this document.

EXAMPLES
       blli:l2=iso8802
              Classical IP over ATM (RFC1577)

       bhli:oui=0x0060D7,id=0x01000001,blli:l2=iso8802
              Arequipa (RFC2170)

       blli:l3=tr9577,ipi=snap,oui=0x00A03E,pid=0x0002
              LAN Emulation

AUTHOR
       Werner Almesberger, EPFL LRC <werner.almesberger@lrc.di.epfl.ch>

Linux                          November 6, 1997                         SAP(7)