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  pre-
       fixed  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 seman-
       tics):

       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  unsup-
       ported. 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=capa-
	      bility. 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)