Timer	Description	Started...	Reset...	On Expiration...
T300	Internal timer. Determines the time the stack must respond to an incoming SETUP. *Note*: If none of the in_calls_behaviour bits are set, the application must initiate this response.	After a SETUP is received.	When the first message in response to the SETUP is sent.	The call is cleared.
T301	ALERT message timing.	After an ALERT is received.	When a CONN is received.	The call is cleared.
T302	Overlap receiving timer.	After a SETUP_ACK is sent.	When an INFO is received.	The call is cleared.
T303	Setup message timing.	After a SETUP is sent.	When a CALL_PROC, ALERT, SETUP_ACK, REL_COM is received.	The call is cleared with a REL_COM.
T304	Control of overlapped sending state.	After a INFO is sent.	When an INFO is received.	A DISC is sent.
T305	Disconnection control.	After a DISC is sent.	When a REL or REL_COM is received.	The link is placed in maintenance state and CRVs are released.
T306	Call is in disconnect indication.	After a DISC with progress indicator is received.	When a REL or DISC is received.	A REL is sent on the line (ACU_CLEAR_CO is sent to the application).
T307	Internal timer.	After SUSPEND_ACK is sent.	When a RESUME_ ACK is received.	The call is cleared (ACU_CLEAR_CO is sent to the application).
T308	Release message control.	After a REL is sent.	When a REL or REL_COM is received.	The link is placed in maintenance state and CRVs are released.
T309	Allows the data link to be dropped without losing calls.	After a data link release message is sent.	When a data link establish message is received.	All calls are cleared locally.
T310	Used to govern the behavior of CALL_PROC.	After a CALL_PROC is received.	When an ALERT, CONN, DISC, or PROG is received.	A DISC is sent.
T313	Controls the behavior of CONN message.	After a CONN is sent.	When CONN_ACK is received.	A DISC is sent.
T314	Future usage for segmented messages.	After a message segment is received.	After last message segment is received.	The incomplete message is discarded.
T316	RESTART procedure timing.	After a RESTART is sent.	----	A RESTART is sent and the timer is restarted.
T317	Controls the internal clearing of CRVs after a RESTART.	After a RESTART is received.	----	A maintenance indication sent to the application.
T318	Used when the state of the call is suspend request.	When a RESUME message is sent.	When a RESUME_ ACK, RESUME_ REJ is received.	The call is cleared (ACU_CLEAR_CO is sent to the application).
T319	Used when the state of the call is suspend request.	When a SUSPEND message is sent.	When a SUSPEND_ACK, SUSPEND_REJ is received.	ACU_CLEAR_CO is sent to the application.
T320	Internal timer.	When a DL establishment indication or confirmation is received.	When a call request packet or DL_RELEASE is received.	DL_RELEASE request is sent to the line.
T321	Controls the internal timing of backup D channels.	----	----	----
T322	Controls the behavior of STATUS_ ENQUIRY.	After a STATUS_ ENQUIRY is sent.	When a STAT, DISC, REL, or REL_COM is received.	STATUS_ENQUIRY is submitted.

Version

Appendix E

Timer Values

Introduction

Timer Functions

Timer Values

: France VN6 Layer 3 Timer Defaults
: EuroISDN Layer 3 Timer Defaults
: AT&T E10 Layer 3 Timer Defaults
: Nortel DMS 100 Layer 3 Timer Defaults
: USA National ISDN-2 Layer 3 Timer Defaults
: Australian Telecom 1 Layer 3 Timer Defaults
: Hong Kong Telephone Layer 3 Timer Defaults
: INS-1500 NTT Layer 3 Timer Defaults
: AT&T 4ESS Layer 3 Timer Defaults
: Korean (and Taiwan) Layer 3 Timer Defaults
: QSIG Layer 3 Timer Defaults

Introduction

This appendix lists the values assigned to various ISDN timers for different country variants. These timers control the behavior of network signaling layer 3 in the ISDN protocol stack.
These values are included as timer_val_t structures in the ISDN_ PROTOCOL_PARMS_Q931CC and ISDN_PROTOCOL_PARMS_LAPD structures referenced by isdnStartProtocol.

Timer Functions

The following table summarizes the meanings of the timers. The items shown in all capital letters are the names of Q.931 messages. For example, ALERT refers to the alert message indicating that an incoming call has arrived.

Timer

Description

Started...

Reset...

On Expiration...

T300

Internal timer. Determines the time the stack must respond to an incoming SETUP.
Note: If none of the in_calls_behaviour bits are set, the application must initiate this response.

After a SETUP is received.

When the first message in response to the SETUP is sent.

The call is cleared.

T301

ALERT message timing.

After an ALERT is received.

When a CONN is received.

The call is cleared.

T302

Overlap receiving timer.

After a SETUP_ACK is sent.

When an INFO is received.

The call is cleared.

T303

Setup message timing.

After a SETUP is sent.

When a CALL_PROC, ALERT, SETUP_ACK, REL_COM is received.

The call is cleared with a REL_COM.

T304

Control of overlapped sending state.

After a INFO is sent.

When an INFO is received.

A DISC is sent.

T305

Disconnection control.

After a DISC is sent.

When a REL or REL_COM is received.

The link is placed in maintenance state and CRVs are released.

T306

Call is in disconnect indication.

After a DISC with progress indicator is received.

When a REL or DISC is received.

A REL is sent on the line (ACU_CLEAR_CO is sent to the application).

T307

Internal timer.

After SUSPEND_ACK is sent.

When a RESUME_ ACK is received.

The call is cleared (ACU_CLEAR_CO is sent to the application).

T308

Release message control.

After a REL is sent.

When a REL or REL_COM is received.

The link is placed in maintenance state and CRVs are released.

T309

Allows the data link to be dropped without losing calls.

After a data link release message is sent.

When a data link establish message is received.

All calls are cleared locally.

T310

Used to govern the behavior of CALL_PROC.

After a CALL_PROC is received.

When an ALERT, CONN, DISC, or PROG is received.

A DISC is sent.

T313

Controls the behavior of CONN message.

After a CONN is sent.

When CONN_ACK is received.

A DISC is sent.

T314

Future usage for segmented messages.

After a message segment is received.

After last message segment is received.

The incomplete message is discarded.

T316

RESTART procedure timing.

After a RESTART is sent.

----

A RESTART is sent and the timer is restarted.

T317

Controls the internal clearing of CRVs after a RESTART.

After a RESTART is received.

----

A maintenance indication sent to the application.

T318

Used when the state of the call is suspend request.

When a RESUME message is sent.

When a RESUME_ ACK, RESUME_ REJ is received.

The call is cleared (ACU_CLEAR_CO is sent to the application).

T319

Used when the state of the call is suspend request.

When a SUSPEND message is sent.

When a SUSPEND_ACK, SUSPEND_REJ is received.

ACU_CLEAR_CO is sent to the application.

T320

Internal timer.

When a DL establishment indication or confirmation is received.

When a call request packet or DL_RELEASE is received.

DL_RELEASE request is sent to the line.

T321

Controls the internal timing of backup D channels.

----

----

----

T322

Controls the behavior of STATUS_ ENQUIRY.

After a STATUS_ ENQUIRY is sent.

When a STAT, DISC, REL, or REL_COM is received.

STATUS_ENQUIRY is submitted.

Timer Values

The following tables indicate the values of the timers for each of the supported operators.

France VN6 Layer 3 Timer Defaults

timer_val_t vn6[VN6_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
VN6_T300	1	1
VN6_T301	180	0
VN6_T302	15	15
VN6_T303	4	10
VN6_T304	20	30
VN6_T305	30	30
VN6_T306	30	0
VN6_T307	180	0
VN6_T308	4	4
VN6_T309	90	90
VN6_T310	20	60
VN6_T312	4	0
VN6_T313	0	4
VN6_T314¹	4	4
VN6_T316¹	120	120
VN6_T317¹	100	100
VN6_T318	0	4
VN6_T319	0	4
VN6_T320	30	0
VN6_T321	30	0
VN6_T322	4	4
VN6_T399	0	10

¹ Not exposed to the API.

EuroISDN Layer 3 Timer Defaults

timer_val_t ets[ETS_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
ETS_T300	1	1
ETS_T301	180	0
ETS_T302	15	15
ETS_T303	4	4
ETS_T304	20	30
ETS_T305	30	30
ETS_T306	30	0
ETS_T307	180	0
ETS_T308	4	4
ETS_T309	90	90
ETS_T310	40	45
ETS_T312	6	0
ETS_T313	0	4
ETS_T316¹	120	120
ETS_T317¹	100	100
ETS_T318	0	4
ETS_T319	0	4
ETS_T320	30	0
ETS_T321	30	0
ETS_T322	4	4

¹ Not exposed to the API.

AT&T E10 Layer 3 Timer Defaults

timer_val_t e10[E10_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
E10_T300	2	2
E10_T303	4	4
E10_T305	4	4
E10_T306	4	0
E10_T308	4	4
E10_T309	90	90
E10_T310	10	45
E10_T313	N/A	4
E10_T316¹	30	30
E10_T317¹	120	120
E10_T321¹	5	5
E10_TSRV¹	0	60

¹ Not exposed to the API.

Nortel DMS 100 Layer 3 Timer Defaults

timer_val_t dms[DMS_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
DMS_T300	1	1
DMS_T301	180	0
DMS_T303	4	4
DMS_T305	30	30
DMS_T308	4	4
DMS_T309	90	90
DMS_T310	10	45
DMS_T312	6	4
DMS_T313	N/A	4
DMS_T316¹	120	120
DMS_T317¹	0	100
DMS_T321¹	40	40
DMS_T322	4	0
DMS_T3DW¹	5	5
DMS_T3M1¹	120	120
DMS_T3MB¹	5	5
DMS_TSPID¹	0	20

¹ Not exposed to the API.

USA National ISDN-2 Layer 3 Timer Defaults

timer_val_t ni2[NI2_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
NI2_T300	1	1
NI2_T301	180	0
NI2_T302	15	0
NI2_T303	5	4
NI2_T305	30	30
NI2_T306	60	0
NI2_T308	4	4
NI2_T309	30	30
NI2_T310	40	0
NI2_T313	4	4
NI2_T316¹	30	30
NI2_T317¹	20	20
NI2_T321¹	5	40
NI2_TSPID¹	0	20

¹ Not exposed to the API.

Australian Telecom 1 Layer 3 Timer Defaults

timer_val_t au1[AU1_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
AU1_T300	1	1
AU1_T302	15	0
AU1_T303	4	15
AU1_T305	30	30
AU1_T306	60	0
AU1_T308	4	4
AU1_T309	2	90
AU1_T310	10	0
AU1_T312	6	4
AU1_T316¹	30	30
AU1_T317¹	25	25
AU1_T322	4	4

¹ Not exposed to the API.

Hong Kong Telephone Layer 3 Timer Defaults

timer_val_t hkt[HKT_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
HKT_T300	1	1
HKT_T301	180	180
HKT_T302	10	15
HKT_T303	4	4
HKT_T304	20	15
HKT_T305	30	30
HKT_T306	30	0
HKT_T307	180	0
HKT_T308	4	4
HKT_T309	90	90
HKT_T310	10	10
HKT_T312	6	4
HKT_T313	4	4
HKT_T314¹	4	4
HKT_T316¹	120	120
HKT_T317¹	90	100
HKT_T318	0	4
HKT_T319	0	4
HKT_T320	30	0
HKT_T321	30	30
HKT_T322	4	4

¹ Not exposed to the API.

INS-1500 NTT Layer 3 Timer Defaults

timer_val_t ntt[NTT_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
NTT_T300	3	3
NTT_T301	180	0
NTT_T303	5	5
NTT_T305	30	30
NTT_T306	30	0
NTT_T307	180	0
NTT_T308	4	4
NTT_T309	90	90
NTT_T310	10	45
NTT_T312	6	4
NTT_T313	4	4
NTT_T314¹	4	4
NTT_T316¹	120	120
NTT_T317¹	100	100
NTT_T318	0	4
NTT_T319	0	4
NTT_T322	4	4
NTT_T3JA	0	50

¹ Not exposed to the API.

AT&T 4ESS Layer 3 Timer Defaults

timer_val_t at4[AT4_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
AT4_T300	1	1
AT4_T303	4	4
AT4_T305	4	4
AT4_T306	60	4
AT4_T308	4	90
AT4_T309	90	30
AT4_T310	10	4
AT4_T313	N/A	4
AT4_T316¹	120	120
AT4_T317¹	0	0
AT4_T321¹	40	40
AT4_T3M1¹	120	120

¹ Not exposed to the API.

Korean (and Taiwan) Layer 3 Timer Defaults

timer_val_t kor[KOR_T_LAST] 



 Timer Index

 Value (Network Side, in seconds)

 Value (User side, in seconds)


 T300

 1

 1


 T301

 180

 N/A


 T302

 15

 15


 T303

 4

 4


 T304

 20

 30


 T305

 30

 30


 T306

 30

 N/A


 T307

 180

 N/A


 T308

 4

 4


 T309

 90

 90


 T310

 40

 45


 T312

 6

 0


 T313

 N/A

 4


 T314

 4

 4


 T316

 120

 120


 T317

 100

 100


 T318

 0

 4


 T319

 0

 4


 T320

 30

 0


 T321

 30

 0


 T322

 4

 4


 T-HOLD

 4

 4


 T_RETRIEVE

 4

 4

Timer Index	Value (Network Side, in seconds)	Value (User side, in seconds)
T300	1	1
T301	180	N/A
T302	15	15
T303	4	4
T304	20	30
T305	30	30
T306	30	N/A
T307	180	N/A
T308	4	4
T309	90	90
T310	40	45
T312	6	0
T313	N/A	4
T314	4	4
T316	120	120
T317	100	100
T318	0	4
T319	0	4
T320	30	0
T321	30	0
T322	4	4
T-HOLD	4	4
T_RETRIEVE	4	4

QSIG Layer 3 Timer Defaults

timer_val_t qsi[QSI_T_LAST]


Timer Index	Value (Network side, in seconds)	Value (User side, in seconds)
QSI_T300	1	1
QSI_T301	180	180
QSI_T302	15	15
QSI_T303	4	4
QSI_T304	20	20
QSI_T305	30	30
QSI_T308	4	4
QSI_T309	90	90
QSI_T310	30	30
QSI_T313	4	4
QSI_T314¹	4	4
QSI_T316¹	120	120
QSI_T322	4	4

¹ Not exposed to the API.

Version

Want to send us feedback on our documentation? Email: Tech_Pubs@nmss.com