1SAP(7)                           Miscellaneous                          SAP(7)
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NAME

6       sap - Service Access Point specification
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DESCRIPTION

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
14       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
20       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
26       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
32       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
36       iso=1-8 bytes
37              ISO
38
39       user=1-8 bytes
40              User-specific
41
42       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
47       oui=3 bytes,id=4 bytes
48              Vendor-specific application identifier
49
50       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
55       l2=iso1745
56              Basic mode ISO 1745
57
58       l2=q291
59              ITU-T Q.291 (Rec. I.441)
60
61       l2=lapb
62              Extended LAPB, half-duplex (Rec. T.71)
63
64       l2=iso8802
65              LAN LLC (ISO/IEC 8802/2)
66
67       l2=x75 ITU-T X.75, SLP
68
69       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
76       l2=x25_ml ...
77              ITU-T X.25, multilink
78
79       l2=hdlc_arm ...
80              HDLC ARM (ISO/IEC 4335)
81
82       l2=hdlc_nrm ...
83              HDLC NRM (ISO/IEC 4335)
84
85       l2=hdlc_abm ...
86              HDLC ABM (ISO/IEC 4335)
87
88       l2=q992 ...
89              ITU-T Q.922
90
91       l2=iso7776 ...
92              ISO 7776 DTE-DTE
93
94       l2=user,info=information
95              User-specified. information is an integer in the range 0 to 255.
96
97       For  layer  three, the following (again, mutually exclusive) possibili‐
98       ties exist:
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100       l3=iso8473
101              ITU-T X.233 | ISO/IEC 8473
102
103       l3=t70 ITU-T T.70 minimum network layer
104
105       l3=h321
106              ITU-T Recommendation H.321
107
108       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
115       l3=iso8208 ...
116              ISO/IEC 8208
117
118       l3=x223 ...
119              ITU-T X.223 | ISO/IEC 8878
120
121       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
127       l2=user,info=information
128              User-specified, see above.
129
130       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
137       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

EXAMPLES

143       blli:l2=iso8802
144              Classical IP over ATM (RFC1577)
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146       bhli:oui=0x0060D7,id=0x01000001,blli:l2=iso8802
147              Arequipa (RFC2170)
148
149       blli:l3=tr9577,ipi=snap,oui=0x00A03E,pid=0x0002
150              LAN Emulation
151

AUTHOR

153       Werner Almesberger, EPFL LRC <werner.almesberger@lrc.di.epfl.ch>
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157Linux                          November 6, 1997                         SAP(7)
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