[CM]

This should be a simple question but I can’t find a definitive answer in 3GPP specs.

How long can a GPRS TBF be in blocks?

The BSN field is 7 bits but the specs say that the BSN field contains the BSN mod SNS, which suggests to me that the BSN can be longer than 7 bits.

But I think the specs also say that if the MS receives two blocks with the same BSN then it will only accept the first.

So can I have more than 128 blocks in a GPRS TBF?

[Pan]

Dear, CM!
If you are still interested this question.. There is no strictly defined restrictions on TBF lenghth. BSN parameter is used for Backward error correction and sequence control, also for correct re-assembly LLC PDU on receiver side. There is no such rule about two blocks with the same BSN, but there is one that each subsequent received block has to have BSN = [BSNprevious block +1] mod128.

[Author]

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