Telecommunications - Configuration of X.25 Networks

 

UKa specific Subscription options

Where a subscription option is related to an X.2 option it is included in section 6. Only the remaining options are included in this section.

7.1 Subscription options - PVCs

Although UKa equipment supports PVCs a marketing decision has been made not to accept any new PVCs onto the network.

TXDTES Q 011:Do you wish to define any PVCs?

|TXDTES Q011|Do you wish to define any PVCs................#TXDTES Q 012:Enter starting logical channel group number

|TXDTES Q012|Enter starting logical channel group number...#TXDTES Q 013:Enter maximum number of VCs

|TXDTES Q013|Enter maximum number of VCs...................#

Details of the PVC are entered by using the PVC table build program.

ONA compatibility

RD 0004 part 8:1.C (PICS proforma Public Network1984)

Vp - Service PVC ............................... P = Prohibited

Therefore release 4 is compatible with ONA for this option.


7.2 Non X.2 Subscription options - Counters and timers

Under certain circumstances the network requires the DTE to respond within a stated maximum time. These parameters allow these times to be set on a per-line basis.

TNDTED Q142(was q25 ) frame retransmission count ( ) (1-255)

|TNDTED Q142| q25 | frame retransmission count (n2).....#standard Public Network settings = 20

number of times network will transmit a frame on expiration of timer T1.

TNDTED Q143(was q26 ) frame retransmission timer ( ) (1-255)

|TNDTED Q143| q26 | frame retransmission timer (t1).....#in 100ms increments

the period of time after which the retransmission of an unacknowledged frame may be initiated.

standard Public Network settings =

Window size 2 4 5 7
Line speed
Packet size 128 256 512 1024
2400 20 30 60 110
9600 19200 10 10 20 30
48000 64000 5 5 5 10

TNDTED Q187(was q75 ) dte congestion timer (1-255)

|TNDTED Q187| q75 | dte congestion timer................#default 60

standard Public Network settings = 60

timer duration for packet level . If the timer expires and the DTE line is still congested, the calls are reset until the line exits congestion.

TNDTED Q188(was q76 ) restart indication interval (6-254)

|TNDTED Q188| q76 | restart indication interval.........#default 60

standard Public Network settings = 60

- time interval between retransmissions of a restart indication packet. A restart indication packet is retransmitted if the DTE does not respond to the packet.

TNDTED Q189(was q77 ) restart indication count (0-20,255)

|TNDTED Q189| q77 | restart indication count............#default 2

standard Public Network settings = 4

the maximum number of retransmissions of a restart indication packet that is sent (255=unlimited)

TNDTED Q190(was q78 ) i/c call timer (6-254)

|TNDTED Q190| q78 | i/c call timer......................#default 180

standard Public Network settings = 180

- the delay between sending an incoming call packet and clearing the call when the timer expires.

TNDTED Q191(was q79 ) reset interval value (6-254)

|TNDTED Q191| q79 | reset interval value................#default 60

standard Public Network settings = 60

- delay between retransmissions of reset indication packets.

TNDTED Q192(was q80 ) reset count (0-20,255)

|TNDTED Q192| q80 | reset count.........................#default 2

standard Public Network settings = 4

maximum number of retransmissions of reset indication packets

(255=unlimited)

TNDTED Q193(was q81 ) clear interval (6-254)

|TNDTED Q193| q81 | clear interval......................#default 60

standard Public Network settings = 60

- time interval between retransmissions of a clear indication packet.

TNDTED Q194(was q82 ) clear count (0-20,255)

|TNDTED Q194| q82 | clear count.........................#default 2

standard Public Network settings = 4

maximum number of retransmissions of a clear indication packet.

ONA compatibility

RD 0004 part 8:1.C (PICS proforma Public Network1984)

Counters and Timers in ONA refer to DTE timers - not DCE timers. No minimum and maximum values are specified.

Therefore release 4 is compatible with ONA for this option.


7.3 Non X.2 Subscription options - Enhanced DTE

Enables the extended form of CALL and CLEAR packets.

TNDTED Q165(was q49 ) enhanced DTE (YES/NO)

|TNDTED Q165| q49 | enhanced DTE........................#standard Public Network settings = YES if 'extended format' is subscribed to, otherwise NO.

If a DTE is defined as non-enhanced, negotiation of facilities and the redirection capability are not available options.

ONA compatibility

RD 0004 part 8:1.C (PICS proforma Public Network1984)

SP1e - CALL REQUEST - extended format............ M = Mandatory

SP2e - CALL CONNECTED - extended format............ M = Mandatory

SP3e - INCOMING CALL - extended format............ M = Mandatory

SP4e - CALL ACCEPTED - extended format............ M = Mandatory

CP1e - CLEAR INDICATION extended format............ M = Mandatory

CP2e - CLEAR REQUEST - extended format............ M = Mandatory

CP4e - CLEAR CONFIRMATION - extended format........ M = Mandatory

Therefore release 4 is compatible with ONA for this option.


7.4 Non X.2 Subscription options - receipt of transit delay

TNDTED Q121( new ) DTE receipt of transit delay (Yes/No)

|TNDTED Q121| new | DTE receipt of transit delay.........#

permits receipt of transit delay selection and indication on a per call basis.

UKa answers

Question: What value will be returned by the TP4 in the Transit delay indication facility? will this give customers information about the number of hops the call will take across the network ? can this be prevented ?

Answer : The value returned by the TP4 for X25 DTE's is the remote TPs "Transit Delay Factor" multiplied by the hopcount incremented by one. For X75 STE's the TDS requested is added to this figure.

TSYSP83 template Q151 :-

- Enter TP Transit Delay Factor in Milliseconds.

This will not explicitly give information on the hop count

to customers.

If you do not wish to allow your customers to use this then

you can prevent them by setting TNDTED71 Q13(X75),Q125(X25)

to No.

Q13 : Does STE subscribe to receipt of Transit Delay (TDSI)

Q125: Does DTE subscribe to receipt of Transit Delay (TDSI)

ONA compatibility

RD 0004 part 8:1.C (PICS proforma Public Network1984)

FS12 - Transit Delay selection and indication...... M = Mandatory

FR12 - Transit Delay selection and indication...... M = Mandatory

we need to check this out.

Test plan and implementation issues


7.5 Non X.2 Subscription options - non zero cause codes

TNDTED Q182(was q70 ) non zero cause codes

|TNDTED Q182| q70 | non zero cause codes................#Answering YES to this question will allow the DTE to pass a non-zero restart cause to the network or pass a non-zero clearing cause or non-zero reset cause through the network should a problem occur.

ONA compatibility

RD 0004 part 8:1.C (PICS proforma Public Network1984)

Y1d - RESTART REQUEST - cause = 128 ............. P = Prohibited

Y1e - RESTART REQUEST - cause = other............ P = Prohibited

Y2a - RESTART INDICATION cause = 0 or 128....... M = Mandatory

Y2b - RESTART INDICATION cause = not 0 or 128... M = Mandatory

Y3d - CLEAR REQUEST - cause = 128 ............. P = Prohibited

Y3e - CLEAR REQUEST - cause = other............ P = Prohibited

Y4a - CLEAR INDICATION cause = 0 or 128....... M = Mandatory

Y4b - CLEAR INDICATION cause = not 0 or 128... M = Mandatory

Y5d - RESET REQUEST - cause = 128 ............. P = Prohibited

Y5e - RESET REQUEST - cause = other............ P = Prohibited

Y6a - RESET INDICATION cause = 0 or 128....... M = Mandatory

Y6b - RESET INDICATION cause = not 0 or 128... M = Mandatory

Therefore release 4 is compatible with ONA for this option.

Test plan and implementation issues

*** need to test out - Do both ends of the call have to be DX2 for this option - or just the originator of the RESTART/CLEAR/RESET.

*** can DTEs use 0 and 128 to 255

could be some problems when we roll out due to DTEs receiving new cause codes in the range 128-255, when their own port subscriptions have not changed.


7.5 per-line 'network tuning' parameters


7.6 Non X.2 Subscription options -

per-line 'network tuning' parameters

TNDTED Q144(was q27 ) disable congestion control (Yes/No)

|TNDTED Q144| q27 | disable congestion control..........#default NO

standard Public Network settings = NO

TP4/IIs are equipped with the capability to monitor their use of memory buffers for communications. If congestion control is enabled, a TP can reject further incoming traffic until it has cleared the traffic stored in its memory. Congestion control is accomplished at the link and packet levels. An entry of yes disables congestion control.

TNDTED Q145(was q28 ) congestion - link level lower threshold

|TNDTED Q145| q28 | congestion - link level lower thres.#(1-255)

default 50

standard Public Network settings = 40

Number of memory buffers in the frame transmission queue as a threshold for leaving the congested state at the link level. If the TP has released enough buffers to get down to this level, the DTE will exit link level congestion.

TNDTED Q146(was q29 ) congestion - link level upper threshold

|TNDTED Q146| q29 | congestion - link level upper thres.#(1-255)

default 100

standard Public Network settings = 55

Number of memory buffers in the frame transmission queue to establish link level congestion. If this or a higher number of buffers is queued, the X.25 line has entered link level congestion. The number entered must be larger than the number entered in Q145

TNDTED Q147(was q30 ) congestion - packet upper threshold

|TNDTED Q147| q30 | congestion - packet upper threshold.#(1-255)

default 50

standard Public Network settings = 35

Number of memory buffers in the packet transmission queue to establish packet level congestion. If this or a higher number of buffers is queued, the X.25 line has entered packet level congestion.

- 'network tuning' parameters ... continued

TNDTED Q148(was q31 ) congestion - packet lower threshold

|TNDTED Q148| q31 | congestion - packet lower threshold.#(1-255)

default 100

standard Public Network settings = 50

Number of memory buffers in the packet transmission queue as a threshold for leaving the congested state at the packet level. If the TP has released enough buffers to get down to this level, the DTE will exit packet level congestion. The number entered in this question must be larger than the number entered in Q147

Test plan and implementation issues

Customers are not given the option to modify these parameters and should normally be built with standard values.

We do not have suitable test equipment for congestion tests and cannot therefore measure the effect of changing these parameters.


7.7 Non X.2 Subscription options - per-line Call priority

Traffic over Public Network has 4 levels of priority, the highest level is network management traffic, then 3 levels are assigned for user traffic, all users are currently built for low.

The priority applies to call setup only, once the call is established the data throughput is not affected.

**** check ****

TNDTED Q176(was q61 ) low,medium or high call priority assign

|TNDTED Q176| q61 | low,medium or high call priority....#(LOW,MEDIUM,HIGH) default LOW

standard Public Network settings = LOW

establishes the default call priority that will be assigned by the TP4/II at the call establishment if the DTE does not subscribe to originating of the call priority facility.

TNDTED Q227(was Q114) i/c priority calls (YES/NO) default NO

|TNDTED Q227| Q114 | i/c priority calls..................#standard Public Network settings = NO

The response to this question indicates whether or not the DTE will accept the call priority facility in an incoming call packet.

TNDTED Q228(was Q115) o/g priority calls (YES/NO) default NO

|TNDTED Q228| Q115 | o/g priority calls..................#standard Public Network settings = NO

The response to this question indicates whether or not the DTE is allowed to originate call requests containing the call priority facility.

TNDTED Q230(was Q117) priority facility assignment

|TNDTED Q230| Q117 | priority facility assignment........#(LOW/MEDIUM/HIGH)

default medium

standard Public Network settings = <not answered>

defines the maximum value of the call priority facility that the DTE is allowed to send or receive.

TNDTED Q231(was Q118) medium priority fairness timer (0-255)

|TNDTED Q231| Q118 | medium priority fairness timer.....#default 0

standard Public Network settings = 0

The priority servicing process provides a fairness mechanism, that prevents higher priority traffic from freezing lower priority traffic.

The response to this question determines the value for the timer on the medium priority queue. Expiration of this timer initiates the PFS (priority fairness service) for medium priority traffic. A value of 0 disables the PFS for medium priority traffic.

- Call priority ... continued

TNDTED Q232(was Q119) low priority fairness timer (0-255)

|TNDTED Q232| Q119 | low priority fairness timer.........#default 0

standard Public Network settings = 0

The response to this question determines the value for the timer on the low priority queue. Expiration of this timer initiates the PFS (priority fairness service) for low priority traffic. A value of 0 disables the PFS for low priority traffic.

ONA compatibility

not applicable

Test plan and implementation issues

*** check current values on Public Network

this is not a CCITT option - if it were decided to implement this feature it would need to be tested.


7.7 Multi-user virtual circuit

7.8 Non X.2 Subscription options - Multi-user Virtual circuit

A multi-user Virtual Circuit is a non CCITT option.

It is a VC that can service multiple users on a single VC, that has high traffic volumes and that can accommodate long duration calls.

An example of this might be a VC carrying SNA or BI-SYNC traffic.

Multi-user VCs are effectively built as an overlay network. In other words they have to be defined on all X.25 lines and trunks through which the call will pass.

TNDTED Q233(was Q120) multi-user virtual circuit (0-15)

|TNDTED Q233| Q120 | multi-user virtual circuit..........#default 0

standard Public Network settings = 0

This question enables multi-user VCs on this line and determines the maximum number of Multi-User VCs that are supported on the line. An answer of 0 indicates that Multi-Users VCs are not supported on this line.

ONA compatibility

not applicable

Test plan and implementation issues

It would be a big overhead to implement this on Public Network.

this is not a CCITT option - if it were decided to implement this feature it would need to be tested.


7.9 Non X.2 Subscription options - Accounting parameters

TNDTED Q149(was q32 ) accounting data (YES/NO) default NO

|TNDTED Q149| q32 | accounting data.....................#standard Public Network settings = NO

enables or disables the delivery of accounting data to the NMC computers for billing purposes. yes=suppress all accounting data.

TNDTED Q150(was q33 ) accounting unit (1,2,4,8,16,32,64,128)

|TNDTED Q150| q33 | accounting unit....................#default 64

standard Public Network settings = 64

a measure of total bytes actually transmitted by the DTE rounded up to a specified unit size. For example if set to 64 then the following number of units will be transmitted.

examples:

Bytes transmitted number of units
50 1
64 1
65 2
128 2
147 3

- Accounting parameters ... continued

TNDTED Q151(was q35 ) half call suppression (YES/NO)

|TNDTED Q151| q35 | half call suppression...............#default NO

standard Public Network settings = YES

Selective half-call suppression allows the suppression of half- call accounting records by either the source or destination side of the call. The selection of source or destination suppression is done on a per-TP4 basis using TSYSP template.

On Public Network TSYSP Q3=YES, TSYSP Q4=DEST ie suppress destination. This produces the following half call records:

Call Request Half call records generated at
from to source destination
X.75 X.75 yes yes
X.75 X.25 yes no
X.25 X.75 yes yes
X.75 async yes yes
async X.75 yes yes
X.25 X.25 yes no
X.25 async yes yes
async X.25 yes no
async async yes yes

(applies to both reverse charge and normal calls)

TNDTED Q178(was q66 ) tariff utility

|TNDTED Q178| q66 | tariff utility......................#standard Public Network settings = <not answered>

UKa Answers

Question: Why is TNDTED q178 (tariff utility) an X25 parameter and not an X.75 parameter ?

Answer : Because you can have x.25 tarrifs.


ONA compatibility

not applicable

Test plan and implementation issues

Public Network uses 64 as accounting unit - no other values are currently tested.


7.11 Non X.2 Subscription options - Addressing
NUAs

There are the following restrictions on the NUA that can be allocated to a customer.

Public Network addresses are 12 decimal digits long. The first 4 digits are the DNIC and are always 2342. The 3 digits following the DNIC is the area codes, a particular area code can only be allocated to one packet switching exchange, therefore the users area code will be dependent on their geographical location.

TXDTES Q 023:Enter DTE address (12-digit -Tp3000 or TP4000)

|TXDTES Q023|Enter DTE address (12-digit)..................#

TXDTES Q 026:Enter DTE address (14-digit -host/gateway)

|TXDTES Q026|Enter DTE address (14-digit)..................#

TXDTES Q 027:Enter minimum length of DTE address

|TXDTES Q027|Enter minimum length of DTE address...........# standard Public Network settings = 12

TNDTED Q115(was q5 ) Multiple Address assignment checking

|TNDTED Q115| q5 | Multiple Address assignment check...#(Yes/No)

default No

standard Public Network settings = NO

associates a list of addresses with a switch LPU-LINE pair that subscribes to this utility. The calling address of each call originating from the DTE is validated by the switch against the address list created. If you select MULT you must use the TP5UTIL program to define the address list.

TNDTED Q183(was q71 ) address length value (4-14) default 12

|TNDTED Q183| q71 | address length value................# standard Public Network settings = 14

this question specifies the maximum address length (in bytes) that the local DTE will accept in a call set-up packet.

TNDTED Q196(was q85 ) UKa or alternate style addressing

|TNDTED Q196| q85 | UKa or alternate style address..#(tel,alt)

default tel

standard Public Network settings = TEL

UKa supports two address formats, both in conformance with CCITT X.121

TEL=FORMAT I

Data Network Identifier Code and Network Terminal Number (DNIC+NTN), the current UKa Plan, requires that the address is specified by its international data number.

ALT=FORMAT II

Data Country Code and National Number (DCC+NN) as well as DNIC+NTN. This alternate addressing format allows for abbreviated addresses (NN or NTN only) and requires the use of international data numbers.

UKa answers

Question: Do you have any information about how to use alternate style addressing (Q196).

ANSWER : What info do you have, or not have? do you have the x.121 spec?

I'm not too sure what you are looking for here.


7.11 TAMs facilities

7.12 Non X.2 Subscription options - TAMs facilities

Use of TAMS requires a separate licence fee from UKa, BT do not currently use TAMS, we have no plans to test it out.

TAMS uses a centralised computer (NMC Prime) to validate calls. This is a big overhead on network resources, eg,

* Network Management traffic overhead

* More NMC machines required

* Backup resources required.

TNDTED Q212(was Q100) validation host (YES/NO) default NO

|TNDTED Q212| Q100 | validation host.....................#standard Public Network settings = NO

This question indicates that the DTE is a validation host.

Features available with TAMS

UKa subscriptions TAMS - Single or interactive

transaction validation

* Single transaction validation

can only be used on X.25 or TP3/TP4 async pads

*** check if BTN pad supported

no user interaction required

* Interactive Validation

for asynchronous pads only

validation host interacts directly with the user through a series of prompts and messages to establish and validate network address, user ID, and password.

TNDTED Q219(was Q106) x29 async call screening (YES/NO)

|TNDTED Q219| Q106 | x29 async call screening............#default NO

standard Public Network settings = NO

This question enables the screening of asynchronous calls only. If yes is entered, all other calls are not screened.

TNDTED Q209(was q97 ) DTE receiving ID facility (YES/NO)

|TNDTED Q209| q97 | DTE receiving ID facility...........#default NO

standard Public Network settings = NO

This question indicates that the DTE may receive the UKa ID facility in incoming call packets.

TNDTED Q208(was q96 ) DTE send id facility (YES/NO)

|TNDTED Q208| q96 | DTE send id facility................#default NO

standard Public Network settings = NO

This question indicates that the DTE may send the UKa ID facility in call request packets.

- TAMS ... continued

UKa subscriptions TAMS - Call intercept facility

works with interactive validation to initiate a prompt sequence for the users ID and password.

sequence:

1 - A user attempts a direct connect to a secured host without using an ID password.

2 - The destination switch clears the call back to the source switch with a security violation notice.

3 - The source switch forwards the call and violation notice to the TAMS validation host.

4 - IF the secured host DOES NOT subscribe to call intercept the call is cleared

IF the secured host DOES subscribe to call intercept the validation host interactively prompts for an ID and password and if valid forwards the call.

*** are subscription options required by the calling PAD.

TNDTED Q216(was Q104) receipt of validation error facility

|TNDTED Q216| Q104 | receipt of validation error facil...#(YES/NO)

default NO

standard Public Network settings = NO

This question enables the DTE to receive validation error facilities in a clear packet

UKa subscriptions TAMS - Source address screening

Customers can set-up a pre-authorised validation between any two system addresses by creating an entry in the TAMS Destination Address / Source Address table. Once created, this validation authorises any access attempt from the defined source address to the defined destination address without resource to user identification or passwords.

- TAMS ... continued

UKa subscriptions TAMS - Call screening facilities

* Incoming call screening

sequence:

1 - The destination switch clears invalid calls back to the source switch with a violation notice.

2 - The source switch forwards the call to the TAMS validation host.

3 - validation host checks to see if destination host subscribes to either, call intercept or source address screening

TNDTED Q207(was q95 ) i/c call screening (YES/NO)

|TNDTED Q207| q95 | i/c call screening..................#default NO

standard Public Network settings = NO

This question enables incoming calls to be screened by the validation host. Verification from the validation host is necessary to access this host.

IF Q207=YES AND Q219=NO, all calls are screened.

IF Q207=YES AND Q219=YES only asynchronous calls are screened.

* Outgoing call screening

the outgoing call screening facility serves customers whose networks do not use single transaction validation. Outgoing call screening forces the X.25 host to forward all outbound calls directly to the validation host.

TNDTED Q213(was Q101) outgoing call screening (YES/NO)

|TNDTED Q213| Q101 | outgoing call screening.............#default NO

standard Public Network settings = NO

This question enables outgoing calls to be screened by the validation host

UKa Answers

Question: What is the purpose of TNDTED71 Q217 and Q218 ? are they related to TAMS ?

Q217 : Does the line connect to a validation host.

Q218 : Does the line subscribe to incoming call screening.

Answer : Yes, these both apply to TAMs, BT should answer these "NO"

- TAMS ... continued

UKa subscriptions TAMS - Address association

* Mnemonic addressing

Terminal users can use a mnemonic to access a host rather than trying to remember and enter the 14 digit numerical address.

*** is this PAD only ??? - BTN pad not supported ???

* Address reselection

Customers can use TAMS to reselect destination addresses when a specific host is temporarily unavailable. When implementing this feature, the TAMS validation host automatically and transparently forwards calls to the original network address on to the designated alternative address. This feature allows backup hosts and gateways to be put into service without the active participation of network users.

***** what are the following 2 questions - check with UKa ******

TNDTED Q214(was Q102) sending call forwarding facilities

|TNDTED Q214| Q102 | sending call forwarding facilities..#(YES/NO)

default NO

standard Public Network settings = NO

TNDTED Q215(was Q103) receipt call forwarding facilities

|TNDTED Q215| Q103 | receipt call forwarding facilities..#(YES/NO)

default NO

standard Public Network settings = NO

* Call distribution

Each mnemonic address accepted for validation is automatically assigned to a numeric address within an established set of addresses. Setup by TAMS administrator.

UKa subscriptions TAMS - Secondary password screening

Allows customers to establish a second level password for specified network users.

UKa subscriptions TAMS - Single Line signon

UKa Asynchronous PADs allow you to enter all the profile information required for a network connection as a specially formatted connection request.

UKa subscriptions TAMS - Online password change

TAMS customers can allow their users to change their own first-level passwords during any interactive communication session.


7.12 Other..............................................#

7.13 Non X.2 Subscription options - Other Options

TXDTES Q 017:Is this a ?

|TXDTES Q017|Is this a privileged DTE?.....................# standard Public Network settings = NO

TXDTES Q 019:Is this a

|TXDTES Q019|Is this a prime 200 TIP.......................# standard Public Network settings = NO

TXDTES Q 021:Enter remote machine number

|TXDTES Q021|Enter remote machine number...................# standard Public Network settings = <not asked>

TXDTES Q 028:Is this an ?

|TXDTES Q028|Is this an old-style X.25 DTE?................# standard Public Network settings = NO

TNDTED Q116(was Q128) Is this an old style X.25 DTE (YES,NO)

|TNDTED Q116| Q128 | Is this an old style X.25 DTE.......# default NO

standard Public Network settings = NO

An "old-style" X.25 DTE is one that is operating with CCITT X.25 1976 version. If the X.25 DTE is operating with CCITT X.25 1980/84 version enter NO.

TNDTED Q152(was q36 ) lcn assignment (UP,DOWN) default UP

|TNDTED Q152| q36 | lcn assignment......................# standard Public Network settings = UP

In order to minimise the possibility of a call collision on a logical channel, LCN assignment is normally done:

UP (starting from the lowest available number and working up) for calls from the network to the DTE

DOWN (starting from the highest available number and working downward) for calls from the DTE to the network.

This question controls the way that the Network allocates LCNs

UP is always used on Public Network since this conforms with the CCITT X.25. DOWN could be used, for example, if the remote end is connected to another network.

TNDTED Q169(was q54 ) local end clearing (YES,NO) default NO

|TNDTED Q169| q54 | local end clearing..................# standard Public Network settings = <not asked>

Local end clearing allows the local X.75 gateway to clear a call and disconnect through the local TP4

UKa answers

Question: What is local end clearing TNDTED71 Q169 ? Why is it an X25 parameter and not an X75 parameter?

Answer : Good question. I'll get back to you on this one.

TNDTED Q170(was q55 ) x29 (YES,NO) default YES

|TNDTED Q170| q55 | x29 protocol id.....................# standard Public Network settings = <not asked>

This question allows the DTE to use the X.29 protocol identifier field in call request packets for the transfer of information about the terminal or host.

Enter NO if the X.29 communication must conform strictly to CCITT 1980

TNDTED Q177(was q65 ) (YES,NO) default NO

|TNDTED Q177| q65 | privileged DTE......................# standard Public Network settings = NO

Declaring a DTE to be privileged disables calling address validation for calls originated from the DTE.

This question must always be answered NO on Public Network, otherwise network security is compromised.

TNDTED Q235(was Q123) (YES,NO) default NO

|TNDTED Q235| Q123 | x.25 dial-in port...................# standard Public Network settings = NO

A dial-in port permits prepaid calls to be barred. These ports can also be busied out by the TDT2 to prevent incoming calls for maintenance purposes.

TNDTED Q238(was Q127) Can the DTE pass ' ' indication

|TNDTED Q238| Q127 | Can the DTE pass 'wait for DQ' ind..#(YES NO)

via User Data field - Default NO

standard Public Network settings = NO

TNDTED Q241(was Q130) Can DTE receive 'wait for DQ' indication

|TNDTED Q241| Q130 | Can DTE receive 'wait for DQ' ind...#(YES,NO)

via call intention facility Default NO

standard Public Network settings = NO


20 - Call reconnect on trunk failure

DTE DCE trunk DTE DCE

unique call ID

-- call --_ -------------------_ -- call --_

_-- acc -- _------------------- _-- add ---

_------------------- data transfer ---------------------_

trunk fails

_---CLR F500 * CLR F500 ---_

------- re-est over diff --_

route

same unique call ID

-------- REJ 0 ------------_

_------- REJ 0 -------------

recover any data that may

have been lost on failed

trunk

---------DATA 0 -----------_

_--------------------- data transfer ---------------------_

=================================================================

If the call cannot be re-established

DTE DCE trunk DTE DCE

unique call ID

-- call --_ -------------------_ -- call --_

_-- acc -- _------------------- _-- add ---

_------------------- data transfer ---------------------_

trunk fails

_---CLR F500 * CLR F500 ---_

------- re-est over diff --_

route

same unique call ID

_-- CLR NC ---- --- CLR NC --_

&x75& = y


metadata block
see also:

 

Correspondence about this page

Book Shop - Further reading.

Where I can, I have put links to Amazon for books that are relevant to the subject, click on the appropriate country flag to get more details of the book or to buy it from them.

cover The Essential Guide to Telecommunications (Essential Guide).

Commercial Software Shop

Where I can, I have put links to Amazon for commercial software, not directly related to the software project, but related to the subject being discussed, click on the appropriate country flag to get more details of the software or to buy it from them.

 

This site may have errors. Don't use for critical systems.

Copyright (c) 1998-2022 Martin John Baker - All rights reserved - privacy policy.