ITU-X75

X75 Packet structure: utilities list

bits 8 _ _ _ _ _ _ 1 hex facilities type
0 0 0 0 0 0 0 0 00 Utility marker:
0 0 0 0 0 0 0 1 01 Reverse charging / fast select
0 0 0 0 0 0 1 0 02 Throughput class indication
0 0 0 0 0 1 1 1 07 Tariffs
0 0 0 0 1 0 0 0 08 Called line address modified notification
0 1 0 0 0 0 0 1 41 Transit network identification
0 1 0 0 0 0 1 0 42 Packet size indication
0 1 0 0 0 0 1 1 43 Window size indication
0 1 0 0 0 1 0 0 44 RPOA selection
0 1 0 0 1 0 0 1 49 Transit delay indication
0 1 0 0 1 0 1 1 4A Clearing network identification code
0 1 0 0 1 0 1 0 4B Transit delay selection
1 0 0 0 0 0 0 1 81 Call identifier
0 0 0 0 0 0 1 1 C3 Closed user group indication
0 0 0 0 1 0 0 1 C7 Closed user group with outgoing access indication
TABLE 21/X.75 (ITU)

The coding of the utility field is defined in § 5.4.3 Rec. X.75 (ITU).

X75 Packet structure: network utilities format

bits 8 _ _ _ _ _ _ 1 Class Facilities code: class coding
0 0 x x x x x x A single octet parameter field
0 1 x x x x x x B double octet parameter field
1 0 x x x x x x C triple octet parameter field
1 1 x x x x x x D variable length parameter field
TABLE 20/X.75 (ITU)
bits 8 _ _ _ _ _ _ 1 utilities field: class A format
0 0 x x x x x x Utility code
octet 1 Utility parameter field
bits 8 _ _ _ _ _ _ 1 utilities field: class B format
0 1 x x x x x x Utility code
octets 1-2 Utility parameter field
bits 8 _ _ _ _ _ _ 1 utilities field: class C format
1 0 x x x x x x Utility code
octets 1-3 Utility parameter field
bits 8 _ _ _ _ _ _ 1 utilities field: class D format
1 1 x x x x x x Utility code
octet 1 Utility parameter field length

octets 2-n

Utility parameter field

01 - Reverse charging / Fast select

- Octet : utility code
bits 8-1 01 H
- Octet 1: utility parameter field
bits 8-7 Fast select
bits 6-2 00000
bit 1 Reverse charging
bit 1 Reverse charging
0 Reverse charging not requested

1

Reverse charging requested

bits 8-7 Fast select
0 0 Fast select not requested

0 1

Fast select not requested

1 0

Fast select requested with no restriction on response

1 1

Fast select requested with restriction on response

02 - Throughput class indication

- Octet : utility code
bits 8-1 02 H
- Octet 1: Coding of throughput class
bits 8-5 From the called STE
bits 4-1 From the calling STE
bits dcba Throughput class
0 0 0 0 Reserved

0 0 0 1

Reserved

0 0 1 0

Reserved

0 0 1 1

75

0 1 0 0

150

0 1 0 1

300

0 1 1 0

600

0 1 1 1

1200

1 0 0 0

2400

1 0 0 1

4800

1 0 0 1

4800

1 0 1 0

9600

1 0 1 1

19200

1 1 0 0

48000

1 1 0 1

64000

1 1 1 0

Reserved

1 1 1 1

Reserved

TABLE 22/X.75 (ITU)

07 - Tariffs

- Octet : utility code
bits 8-1 07 H
- Octet 1: utility parameter field
bits 8-4 Primary tariff subfield (PPPPP)
bits 3-1 Secondary tariff subfield (UUU)
bits 8-4 P P P P P Primary tariff subfield
0 0 0 0 0 Subclass code 0: X.25
0 0 0 0 1 Subclass code 1: Switched access X.28
0 0 0 1 0 Subclass code 2: Dedicated access X.28
0 0 0 1 1 Subclass code 3:X.32
0 0 1 0 0 Subclass code 4:X.75
0 0 1 0 1 Subclass code 5-15: Reserved
to Subclass code 16-30: Reserved for national use
0 0 0 0 0 Subclass code 31: Unspecified or non-standard

08 - Called line address modified notification

- Octet : utility code
bits 8-1 08 H
- Octet 1: utility parameter field
bits 8-1 Called line address modified notification
bits 8 7 6 5 4 3 2 1 Called line address modified notification
0 0 0 0 0 1 1 1 Call distribution within a hunt group
0 0 0 0 0 0 0 1 Call redirection due to originally called DTE busy
0 0 0 0 1 0 0 1 Call redirection due to originally called DTE out of order
0 0 0 0 1 1 1 1 Call redirection due to prior request from originally called DTE for systematic call redirection
1 1 x x x x x x Called DTE originated (a)
1 1 x x x x x x Call deflection by the originally DTE(b)

(a): Each X may be independently set to 0 or 1 by the called DTE and is passed transparently.

(b): The Xs are those set by the originally called DTE in the call forwarding selection facility.

41 - Transit network identification

- Octet : utility code
bits 8-1 41 H
- Octet 1: Identification code
bits 8-5 First digit (binary coded decimal)
bits 4-1 Second digit (binary coded decimal)
- Octet 2: Identification code
bits 8-5 Third digit (binary coded decimal)
bits 4-1 Fourth digit (binary coded decimal)

42 - Packet size indication

- Octet : utility code
bits 8-1 42 H
- Octet 1: utility parameter field
bits 8-5 0000
bits 4-1 Packet size from the called STE
- Octet 2: futility parameter field
bits 8-5 0000
bits 4-1 Packet size from the calling STE

The values available for each direction are as follows:

bits 4 3 2 1 Packet size
0 1 0 0 16

0 1 0 1

32

0 1 1 0

64

0 1 1 1

128

1 0 0 0

256

1 1 0 1

512

1 1 0 0

1024

1 1 1 0

2048

1 1 1 1

4096

43 - Window size indication

- Octet : utility code
bits 8-1 43 H
- Octet 1: utility parameter field
bit 8 0
bits 7-1 Window size from the called STE
- Octet 2: utility parameter field
bits 8 0
bits 7-1 Window size from the calling STE

The values of window coded on bits 7-1 are binary encoded.

44 - RPOA selection

- Octet : utility code
bits 8-1 44 H

The parameter field contains the data network identification code DNIC corresponding to the initial RPOA transit network requested.

- Octet 1: Identification code
bits 8-5 First digit (binary coded decimal)
bits 4-1 Second digit (binary coded decimal)
- Octet 2: Identification code
bits 8-5 Third digit (binary coded decimal)
bits 4-1 Fourth digit (binary coded decimal)

49 - Transit delay indication

- Octet : utility code
bits 8-1 49 H
- Octets 1-2: Transit delay
bits 16-1 Number in milliseconds from bit 16 to bit 1 (binary coded).

4A - Clearing network identification code

- Octet : utility code
bits 8-1 4A H
- Octet 1: Identification code
bits 8-5 First digit (binary coded decimal)
bits 4-1 Second digit (binary coded decimal)
- Octet 2: Identification code
bits 8-5 Third digit (binary coded decimal)
bits 4-1 Fourth digit (binary coded decimal)

4B - Transit delay selection

- Octet : utility code
bits 8-1 4B H
- Octets 1-2: Transit delay
bits 16-1 Number in milliseconds from bit 16 to bit 1 (binary coded).

81 - Call identifier

- Octet : utility code
bits 8-1 81 H
- Octets 1-3: Call identifier
bits 24-1 Binary data

C3 - Closed user group indication

- Octet : utility code
bits 8-1 C3 H
- Octet 1: Length in octets of utility parameter field
bits 8-1 0 0 0 0 0 1 0 0 = 04 H
- Octet 2: international interlock code
bits 8-5 First digit (binary coded decimal)
bits 4-1 Second digit (binary coded decimal)
- Octet 3: international interlock code
bits 8-5 Third digit (binary coded decimal)
bits 4-1 Fourth digit (binary coded decimal)
- Octets 4-5: international interlock code
bits 16-1 Remaining 16 bits of the code

C7 - Closed user group with outgoing access indication

- Octet : utility code
bits 8-1 C9 H
- Octet 1: Length in octets of utility parameter field
bits 8-1 0 0 0 0 0 1 0 0 = 04 H
- Octet 2: international interlock code
bits 8-5 First digit (binary coded decimal)
bits 4-1 Second digit (binary coded decimal)
- Octet 3: international interlock code
bits 8-5 Third digit (binary coded decimal)
bits 4-1 Fourth digit (binary coded decimal)
- Octets 4-5: international interlock code
bits 16-1 Remaining 16 bits of the code

X75 L3 parameters: time-limit list

STE X/Y
T30 180s
T31 200s
T32 180s
T33 180s

Time-limit T30

T30 STE X/Y
State r2/r3
Start STE X/Y issues a restart request packet
Stop STE X/Y leaves the r2/r3 state (i.e., the restart confirmation or restart request packet is received)

Time-limit T31

T31 STE X/Y
State p2/p3
Start STE X/Y issues a call request packet
Stop STE X/Y leaves the p2/p3 state (e.g., the call connected, clear request or call request packet is received)

Time-limit T32

T32 STE X/Y
State d2/d3
Start STE X/Y issues a reset request packet
Stop STE X/Y leaves the d2/d3 state (e.g., the reset confirmation or reset request packet is received)

Time-limit T33

T33 STE X/Y
State p6/p7
Start STE X/Y issues a clear request packet
Stop STE X/Y leaves the p6/p7 state (e.g., the clear confirmation or clear request packet is received)

 


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updated:  27-Feb-04