Wireshark-users: Re: [Wireshark-users] 答复: Is that a bug in packet-gsm_sms.c ?
From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Sun, 3 Apr 2011 10:26:40 -0700
On Apr 3, 2011, at 10:22 AM, damker wrote:

> Oh , in 3GPP TS 23.040 the PI is a Mandatory parameter .

Yes.  It's mandatory for both SMS-DELIVER-REPORTs from RP-ERROR and SMS-DELIVER-REPORTs from RP-ACK, unlike the FCS, which is a Mandatory parameter only for SMS-DELIVER-REPORTs from RP-ERROR.