Manpage of EXTRAFORMAT

EXTRAFORMAT

Section: OpenSS7 X.25 Networking Data Structures (5)
Updated: 2008-10-31
Index Return to Main Contents

NAME

extraformat - Non-OSI Quality of Service parameter format structure

INTERFACE

Network Layer Interface (NLI), STREAMS.

SYNOPSIS

#include <netx25/x25_proto.h>
#define MAX_NUI_LEN     64
#define MAX_RPOA_LEN     8
#define MAX_CUG_LEN      2
#define MAX_FAC_LEN     32
#define MAX_TARIFFS      4
#define MAX_CD_LEN      MAX_TARRIFS * 4
#define MAX_SC_LEN      MAX_TARRIFS * 8
#define MAX_MU_LEN      16
struct extraformat {
    unsigned char fastselreq;
    unsigned char restrictresponse;
    unsigned char reversecharges;
    unsigned char pwoptions;
#define NEGOT_PKT   0x01 /* packet size negotiable */
#define NEGOT_WIN   0x02 /* window size negotiable */
#define ASSERT_HWM  0x04 /* concatentation limit assert */
    unsigned char locpacket;
    unsigned char rempacket;
#define DEF_X25_PKT 7 /* the standard default packet size */
    unsigned char locwsize;
    unsigned char remwsize;
#define DEF_X25_WIN 2 /* the standard default window size */
    int nsdulimit;
    unsigned char nui_len;
    unsigned char nui_field[MAX_NUI_LEN];
    unsigned char rpoa_len;
    unsigned char rpoa_field[MAX_RPOA_LEN];
    unsigned char cug_type;
    unsigned char cug_field[MAX_CUG_LEN];
    unsigned char reqcharging;
    unsigned char chg_cd_len;
    unsigned char chg_cd_field[MAX_CD_LEN];
    unsigned char chg_sc_len;
    unsigned char chg_sc_field[MAX_SC_LEN];
    unsigned char chg_mu_len;
    unsigned char chg_mu_field[MAX_MU_LEN];
    unsigned char called_add_mod;
    unsigned char call_redirect;
    struct lsapformat called;
    unsigned char call_deflect;
    unsigned char x_fac_len;
    unsigned char cq_fac_len;
    unsigned char cd_fac_len;
    unsigned char fac_field[MAX_FAC_LEN];
};

MEMBERS

The fields in this structure are:

fastselreq

Applies only to non-OSI applications, for example X.29. A non-zero value means the X.25 facility fast select is to be requested or indicated. Note: For CONS, the use of fast select need not be requested.

restrictresponse

Sets response to be a Clear Request. If the response to a Connect Request or Indication is to be a Disconnect Indication, the filed restrictresponse is non-zero.

reversecharges

A non-zero value means that reverse charging is requested or indicated for this connection. Note: The configuration mode bit, SUB_REVCHARGE, has an impact on whether reverse charging is indicated, since it is possible to select a per-subnetwork-status for receipt of reverse charging.

pwoptions

The pwoptions field is used to indicate per (virtual) circuit options. The field is a bit map interpreted as shown below:

Bit Value Symbol Meaning

bit 0 0 - Packet size negotiation not permitted

1 NEGOT_PKT Packet size negotiation permitted

bit 1 0 - Window size negotiation not permitted

1 NEGOT_WIN Window size negotiation permitted

bit 2 0 - No concatentation limit asserted

1 ASSERT_HWM Assert concatentation limit

This field is used for two reasons:

1.: The X.25 software always indicates the values of the window and packet sizes operating on the virtual circuit. The field pwoptions for an incoming call indicates whether these values are negotiable.
2.: In Connect Requests and Connect Resposnes, the NLI user can set nsdulimit, the limit value for packet concatentation by the X.25 level, to a value different from the limit in the subnetwork configuration database. It is not a negotiable option, so whatever the user requests is used.

locpacket, rempacket

If the fields locpacket and rempacket are non-zero, locpacket contains indicated or negotiated encoded packet sizes for the direction local-to-remote and rempacket contains the indicated or negotiated encoded packet sizes for the direction remote-to-local. The actual packet size is 2 to the power of the value specified. The standard default packet size, DEF_X25_PKT, is 7, (i.e., 128 octets).

locwsize, remwsize

If the fields locwsize and remwsize are non-zero, they contain indicated or negotiated window sizes for the directions local-to-remote and remote-to-local. The standard default window size, DEF_X25_WIN is 2.

nsdulimit

Specifies the packet concatenation limit. If the field nsdulimit is non-zero and the appropriate bit is set in the pwoptions field described above, the nsdulimit specified is ued as the concatentation limit.

nui_len

The length of any Network User Identification used in Call Requests and Responses.

nui_field

Network User Identification used in Call Requests and Responses. This is not available on yellow book X.25 (1980) networks.

nui_len, nui_field

The network user identification (NUI) is used in connect requests and responses. It is not available on yellow book X.25 (1980) networks. If the field nui_len is non-zero, the network user identification is supplied in the nui_field and is of length nui_len octets.

rpoa_len

The length of any RPOA DNIC information used in Call Requests. Valid values for rpoa_len are 0, 4, 8, 12 and 16.

rpoa_field

Any Recognized Private Operating Agency (RPOA) DNIC information. This is used in Call Requests only. It is stored as two BCD digits per byte, right justified.

On yellow book X.25 (1980) networks, this is restricted to one RPOA and 4 BCD digits. Basic format encoding is used.

On red book X.25 (1984) and blue book X.25 (1988) networks, there can be one or more RPOA. Extended format encoding is used if there is more than one RPOA. The maximum number of RPOA is 4.

rpoa_len, rpoa_field

Recognized primitive operating agency (RPOA), used in connect requests only. If the field rpoa_len is non-zero, the RPOA DNIC information is supplied in rpoa_field and is of length rpoa_len semi-octets.

For a yellow book X.25 (1980) network, this is restricted to one RPOA of length 4 semi-octets. The basic format encoding is used for the RPOA selected.

For a red or blue book X.25 (1984 or 1988) network, one or more RPOAs can be selected. The extended format encoding is used only if the number of RPOAs selected is greater than 1. The maximum number of RPOAs selected is restricted to 4. Valid values for rpoa_len are 0, 4, 8, 12 and 16.

cug_type

Closed user group type. Possible values are:

CUG: Closed user group.
BCUG: Bilateral CUG.
0: No CUG used.

cug_field

Any applicable CUG information, stored as two BCD digits per byte, right justified.

Note:: Incoming Close User Group facilities are assumed to have been validated by the network. No further checking is performed.

cug_type, cug_field

This field is used in Connect Requests and Indications only. If the field cug_type is non-zero, the CUG information is supplied right-justified in cug_field. Values for cut_type are as follows:

CUG: Close user group, up to four semi-octets.
BGUG: Bilateral CUG (two members only), four semi-octets.
Note:: Incomfing CUG facilities are assumed to have been validated by the network. No further checking is performed.

reqcharging

Requests call charging in a Call Request or Connect Accept.

chg_cd_len

Gives the length of the chg_cd_field.

chg_cd_field

Specifies dureation of the call if call charging is in use. Used in a Disconnect Indication or Confirmation.

chg_sc_len

Give the length of the chg_sc_field.

chg_sc_field

Specifies segment count if call charging is in use. Used in a Disconnect Indication or Confirmation.

chg_mu_len

Gives the length of the chg_mu_field.

chg_mu_field

Specifies the monetary unit if call charging is in use. Used in a Disconnect Indication or Confirmation.

reqcharging, chg_cd_len, chg_cd_field, chg_sc_len, chg_sc_field, chg_mu_len, chg_mu_field

If the field reqcharging is non-zero in a Connect Request or Indication, Call Charging is requeseted. In a Disconnect Indication or Confirmation, the following fields give the charging information: chg_cd_len and chg_cd_field give the length and value of the call duration; chg_sc_len and chg_sc_field give the length and value of the segment count; chg_mu_len and chg_mu_field give the length and value of the monetary unit. A zero length field means no charging informaion is supplied for the relevant charging category.

called_add_mod

A one-byte field holding the reason for any address modification as defined in X.25 Recommendation[1], encoded as follows:

x0000001: Called DTE busy. Call redirected.
x0000111: Call distribution within hung group.
x0001001: Called DTE out of order. Call redirected.
x0001111: Called DTE has requested systematic redirection.
11000000: Called DTE deflected call.
11000001: Called DTE busy. Gateway redirected call.
11001001: Called DTE out of order. Gateway redirected call.
11001111: Called DTE has requested systematic redirection. Gateway redirected call.

Where x indicates that this bit is 0 if the address modification occured in a public data network and 1 if it occured ina private network.

call_redirect

A one-byte field holding the reason for a call redirection as defined in the X.25 Recommendation[1], encoded as follows:

00000001: Called DTE busy. Call redirected.
00000111: Call distribution within hunt group.
00001001: Called DTE out of order. Call redirected.
00001111: Called DTE has requested systematic redirection.
11000000: Called DTE deflected call.
11000001: Called DTE busy. Gateway redirected call.
11001001: Called DTE out of order. Gateway redirected call.
11001111: Called DTE has requested systematic redirection. Gateway redirected call.

called

Supplies the originally-called DTE address.

call_deflect

A one-byte field holding the reason for call deflection as defined in X.25 Recommendation[1], encoded as follows:

11000000: Called DTE deflected call.
11000001: Called DTE busy. Gateway redirected call.
11001001: Called DTE out of order. Gateway redirected call.
11001111: Called DTE has requested systematic redirection. Gateway redirected call.

deflected

In a Clear Request, contains the DTE address, and if required, the NSAP that a call is to be deflected to.

x_fac_len

Indicates the length of a fac_field relating to X.25 facilities.

cq_fac_len

Indicates the length of a fac_field relating to non-X.25 facilities for the calling network.

cd_fac_len

Indicates the length of a fac_field relating to non-X.25 facilities for the called network.

fac_field

This field is used in Call Requests and Connect Accepts only. It allows for the passing of explicit facility encoded strings for X.25 facilities, and non-X25 facilities for calling and called networks.

Note:: The contents of this field are not validated or acted upon by the code. The X.25 facilities are inserted at the end of any other X.25 facilities which are passed in the Call Request/Accept (for example, packet/window sizes). If any non-X.25 facilities are supplied the appropriate marker is inserted before the supplied facilities. Take care not to duplicate any facilities.

x_fac_len, cq_fac_len, cd_fac_len, fac_field

These fields are used in Connect Requests and Indications only. Provision is made for the passing of explicity facility encoded strings for X.25 facilities, and non-X.25 facilities for calling and called networks. The fields x_fac_len, cq_fac_len and cd_fac_len denote the lengths of the facilities in the field fac_field relating to X.25 facilities, non-X.25 facilities for the calling network, and non-X.25 facilities for the called network. If the length field is zero, this denotes that no facilities are supplied for the corresponding facility category. Note: The contents of this field, if supplied, are not validated or acted upon by the code. The X.25 facilities are inserted at the end of any other X.25 facilities that are passed in the Connect Request/Indication (for example, packet/window sizes). If any non-X.25 facilities are supplied, the appropriate marker is inserted before the supplied facilities.

DESCRIPTION

For those NLI applications that require them, the non-OSI facilities supported are as follows:

*: non-OSI extended addressing;
*: X.25 fast select request/indication with no restriction on response;
*: X.25 fast select reqeust/indication with restriction on response;
*: X.25 reverse charging;
*: X.25 packet size negotiation;
*: X.25 window size negotiation;
*: X.25 network user identification;
*: X.25 recognized private operating agency selection;
*: X.25 closed user groups;
*: X.25 call deflection;
*: X.25 programmable facilities.

NOTICES

The Network Layer Interface (NLI) is a proprietary interface without a formal standard. Either the Network Provider Interface (NPI)[2], npi(7), or the XTI-X25 interface[3], xti_x25(3), should be used in its stead.

FILES

The extraformat structure is defined in the <netx25/x25_proto.h> file.

COMPATIBILITY

The extraformat structure is compatible with NLI, and implementations based on NLI such as Solaris Solstice® X.25 9.2[4], IRIX SX.25[5], HP-UX X.25/9000, PT X.25[6], with the following considerations:

---: Solaris Solstice® X.25 9.2[4], IRIX SX.25[5], PT X.25[6], are consistent in their documentation of the extraformat structure.
---: NLI is an inherently low level and non-portable interface and should not be used by portable programs. Portable programs should use the NPI or XX25 interfaces in its stead.
---: Binary compatibility is not attempted: only a rough source compatibility. Any binary compatibility exhibited is a bug and is scheduled to be removed in the next release.

See NLI(7), STREAMS(4), for additional compatiblity considerations.

CONFORMANCE

The NLI is not a formal standard. The OpenSS7tm implementation of NLI conforms to documentation for Version 3 of the NLI.

HISTORY

The NLI is an interface originally developed by Spider Systems, Ltd. (now a division of Emmerson Power). The NLI interface found its way into may mainstream UNIX implementations and UNIX-like RTOS sporting STREAMS such as Windriver's VxWorks. The NLI was never standardized and remains an inherently non-portable interface.

VERSIONS

This manual page was written for the OpenSS7tm implementation of X.25.

REFERENCES

[1]: ITU-T Recommendation X.25, Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to the public data networks by dedicated circuit, October 1996, (Geneva), ITU, ITU-T Telecommunication Standardization Sector of ITU. (Previously "CCITT Recommendation") <http://www.itu.int/rec/T-REC-X.25/>
[2]: NPI, Open Group CAE Specification: Network Provider Interface (NPI) Specification, Revision 2.0.0, Draft 2, August 17, 1992, (Parsippany, New Jersey), UNIXInternational,Inc., UNIX International Press. <http://www.openss7.org/docs/npi.pdf>
[3]: C411 (XX25), X/Open CAE Specification: X.25 Programming Interface using XTI (XX25), November 1995, (Berkshire, UK), X/Open, Open Group Publication. [ISBN: 1-85912-136-5] <http://www.opengroup.org/onlinepubs/>
[4]: Solstice® X.25, Solstice® X.25 9.2 Programming Guide, October 1999, (Palo Alto, California), Sun Microsystems, Inc., Sun. [Part No: 806-1235-10] <http://docs-pdf.sun.com/>
[5]: IRIX® SX.25, SX.25 NLI Programming's Guide, 1994, (Mountainview, California), Silicon Graphics, Inc., SGI Technical Publications. [Doc. No: 007-2268-002] <http://techpubs.sgi.com/>
[6]: PT X.25, X.25 Protocol User's Manual, 2007, (Rochester, New York), Performance Technologies Inc., PT.

TRADEMARKS

OpenSS7tm: is a trademark of OpenSS7 Corporation.
Linux®: is a registered trademark of Linus Torvalds.
UNIX®: is a registered trademark of The Open Group.
Solaris®: is a registered trademark of Sun Microsystems.

Other trademarks are the property of their respective owners.

IDENTIFICATION

OpenSS7 X.25 Networking: Package strx25 version 0.9.2.1 released 2008-10-31.

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Time: 20:20:39 GMT, May 20, 2013