Telecommunications - Configuration of X.25 Packet Retransmission

 

Subscription Option - Packet Retransmission

This facility, if subscribed to, allows a DTE to request the retransmission of one or several consecutive data packets (which have not yet been acknowledged at the packet level)

This is done by sending a REJ packet.

This facility is not very useful since level 2 ensures error free reception of data, therefore it should not be necessary to retransmit the data.

UK(a) - supported, but not a subscription option, users always get it.

UK(b) - not supported

X.2 LEVEL 3 PER USER SUBSCRIPTION X.2 (1984) UK(a) UK(b) interworking
OPTIONS REF CLASS now now R5a R5b R6
Packet Retransmission 1.7 A . . . .

| Packet Retransmission...............| 1.7 A |

| . | . | . | . | | #

\info\computer\UK\x25-sub\ret-t.t1

&UKa& = yUKa support

DX1: always allowed (not a subscription option)

DX2: yes

TP4/III: ?

This facility already is supported by Public Network (whether the user wants it or not).

At release 4 it will be a table building option.

table build question:

TNDTED Q132( new ) subscribe: reject packet (YES/NO)

|TNDTED Q132| new | subscribe: reject packet.............# default:YES

I cannot think why we would want to turn this facility off. It would allow us to charge extra for packet retransmission, which we already provide ?

UKa Answers

Question:

If we set Packet retransmission to NO would that save any

buffers, or TP resources?

Answer : No.

Question: Does the TP4 ever send a REJ packet to the DTE?

Answer : Yes, either can send Rej.

&UKb& = yUKb support

v 4.03

X.2 1984 ... A - additional service

X.2 1988 ... A - additional service

ISO 8878 compatibility

ONA compatibility

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

DS6 - Responding to packet retransmission requests.. -

DR6 - Requesting packet retransmission........... P = Prohibited

Therefore release 4 is compatible with ONA for this option.

Test plan and implementation issues

Currently Public Network always provides retransmission, it is not currently a subscription option.



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