Wireshark-dev: Re: [Wireshark-dev] Question about displaying of Sequence Number of GTP v2
Date Index · Thread Index · Other Months · All Mailing Lists
Date Prev · Date Next · Thread Prev · Thread Next
From: Pascal Quantin <pascal@xxxxxxxxxxxxx>
Date: Thu, 4 Jun 2020 17:23:13 +0200
Hi,

Le jeu. 4 juin 2020 à 17:11, Дмитрий Кондратьев <dobreczasy@xxxxxxxxx> a écrit :
Good afternoon all.
Recently I discovered that the parameter Sequence Number for GTP v2 protocol is displayed in such way: "Sequence Number: 0x00ffffff (16777215)"
But if you see specs then it is stated that Sequence Number is 24-bit field. From my perspective, it doesn't make sense to include two lead zeros.
Am I missing something? Is it a small UI bug?
Thank you in advance!

There are several sequence numbers in the GTPv2 specification.
The one specified in 3GPP 29.274 chapter 8.114 is 4 bytes long and this is the one matching the gtpv2.sequence_number filter.
The one from the header is 3 bytes long and is using the gtpv2.seq filter. It is wrongly displayed as a FT_UINT32 instead of FT_UINT24. I guess this is the one you are looking at. THanks for the report, it is addressed in https://code.wireshark.org/review/#/c/37379/

Best regards,
Pascal.