1SAP(7) Miscellaneous SAP(7)
2
6 sap - Service Access Point specification
7
9 The text2sap and sap2text functions use the format described in this
10 man page. Because all standard ATM tools on Linux use those functions
11 to convert to or from the textual representation of SAP specifications,
12 they expect them in the same format too.
13 The SAP is divided into two parts: the broadband high layer information
15 (BHLI) and the broadband low layer information (BLLI). A SAP can con‐
16 tain one, both, or none of them. In the latter case, the SAP is usually
17 considered as a wildcard SAP, i.e. a SAP that is compatible with any
18 other SAP.
19 Each part begins with its name (bhli or blli), followed by a colon and
21 a (non-empty) list of attributes, which are of the form
22 attribute=value. Some attributes have sub-attributes, which follow
23 them. Everything that isn't separated by a colon or an equal sign is
24 separated by a comma.
25 Values which are a number of bytes are specified as the corresponding
27 sequence of pairs of hex digits. The sequence can be optionally pre‐
28 fixed with 0x. Values with are integers in a given range can be speci‐
29 fied in decimal (no prefix), octal (0 prefix), and hexadecimal (0x pre‐
30 fix).
31 The following, mutually exclusive attributes are allowed in the bhli
33 part (see the corresponding ATM Forum and ITU documents for the seman‐
34 tics):
35 iso=1-8 bytes
37 ISO
38 user=1-8 bytes
40 User-specific
41 hlp=4 bytes
43 High layer profile. Note that this attribute only exists on UNI
44 3.0. text2sap only recognizes it if your system is configured to
45 accept UNI 3.0 message formats.
46 oui=3 bytes,id=4 bytes
48 Vendor-specific application identifier
49 The structure of the bhli part is more complex. It distinguishes three
51 layers, l1, l2, and l3, of which the first one is presently unsup‐
52 ported. For layer two, the following (mutually exclusive) possibilities
53 exist:
54 l2=iso1745
56 Basic mode ISO 1745
57 l2=q291
59 ITU-T Q.291 (Rec. I.441)
60 l2=lapb
62 Extended LAPB, half-duplex (Rec. T.71)
63 l2=iso8802
65 LAN LLC (ISO/IEC 8802/2)
66 l2=x75 ITU-T X.75, SLP
68 l2=x25_ll ...
70 ITU-T X.25, link layer. This attribute and the following
71 attributes through l2=iso7776 can optionally be followed by one
72 or more of the following sub-attributes: mode=mode (mode of
73 operation, either norm or ext), and window=window size (window
74 size in k, 1-127).
75 l2=x25_ml ...
77 ITU-T X.25, multilink
78 l2=hdlc_arm ...
80 HDLC ARM (ISO/IEC 4335)
81 l2=hdlc_nrm ...
83 HDLC NRM (ISO/IEC 4335)
84 l2=hdlc_abm ...
86 HDLC ABM (ISO/IEC 4335)
87 l2=q992 ...
89 ITU-T Q.922
90 l2=iso7776 ...
92 ISO 7776 DTE-DTE
93 l2=user,info=information
95 User-specified. information is an integer in the range 0 to 255.
96 For layer three, the following (again, mutually exclusive) possibili‐
98 ties exist:
99 l3=iso8473
101 ITU-T X.233 | ISO/IEC 8473
102 l3=t70 ITU-T T.70 minimum network layer
104 l3=h321
106 ITU-T Recommendation H.321
107 l3=x25 ...
109 ITU-T X.25, packet layer. This attribute and the following
110 attributes through l3=x223 can optionally be followed by one or
111 more of the following sub-attributes: mode=mode (see above),
112 size=default packet size (4-12, corresponding to 16-4096), win‐
113 dow=window size (see above).
114 l3=iso8208 ...
116 ISO/IEC 8208
117 l3=x223 ...
119 ITU-T X.223 | ISO/IEC 8878
120 l3=tr9577,ipi=identifier ...
122 ISO/IEC TR 9577. identifier is the initial protocol identifier
123 in the range 0-255. For SNAP (0x80), the keyword snap can be
124 used, and the following sub-attributes have to be specified:
125 oui=3 bytes, and pid=2 bytes.
126 l2=user,info=information
128 User-specified, see above.
129 l3=h310 ...
131 ITU-T Recommendation H.310. The sub-attribute term=type (termi‐
132 nal type, rx, tx, or rxtx) is recognized. If present, it enables
133 the two additional sub-attributes fw_mpx=capability (forward
134 multiplexing capability, ts, ts_fec, ps, ps_fec, or h221) and
135 bw_mpx=capability. Both are optional.
136 Note that commas must never follow colons or other commas. Also, white‐
138 space is not allowed inside a SAP specification. SAP specifications are
139 case-insensitive. On input, items must be written in exactly the order
140 used in this document.
141
143 blli:l2=iso8802
144 Classical IP over ATM (RFC1577)
145 bhli:oui=0x0060D7,id=0x01000001,blli:l2=iso8802
147 Arequipa (RFC2170)
148 blli:l3=tr9577,ipi=snap,oui=0x00A03E,pid=0x0002
150 LAN Emulation
151
153 Werner Almesberger, EPFL LRC <werner.almesberger@lrc.di.epfl.ch>
154Linux November 6, 1997 SAP(7)