SMSoverNAS in NR

#SMSoverNAS in NR, below is my understanding on Octet#3 of RP-Destination Address encoding.??

**************************************************************************

TS 24.011 7.3.1.2 RP-DATA (Mobile Station to Network)

This message is sent in MS -> MSC direction. The message is used to relay the TPDUs. The information elements are in line with 3GPP TS 23.040.

8.2.5.2 Destination address element:

In the case of MO transfer, this element contains the destination Service Centre address.?The RP-Destination Address information element is coded as shown in figure 8.6/3GPP TS 24.011.The RP-Destination Address is a type 4 information element. In the mobile station to network direction the minimum value of the length octet is 2 and the maximum value is 11.?In the network to mobile station direction, the value of the length octet of the element is set to 0.

The number digit(s) in octet 4 precede the digit(s) in octet 5 etc. The number digit which would be entered first is located in octet 4, bits 1 to 4. If the RP-Destination Address contains an odd number of digits, bits 5 to 8 of the last octet shall be filled with an end mark coded as "1111". Since the information element contains the complete RP-Destination Address there is no need for an additional complete indication.

The contents of octets 3, 4, etc. are the same as those defined for the Called Party BCD Number IE defined in 3GPP TS 24.008 [5].

TS 24.008 9.3.23.1.4a Called party BCD number

For all bands except for PCS1900, the maximum length of this IE sent by the network shall be 13 octets.

**************************************************************************

How National Number would be encoded?

National Number 10 (decimal) is "1: 0 0 0 0" in BCD coding.?

Will 1st digit (1:) be ignored while encoding RP-Destination Address? How UE NAS will map these four bits "0 0 0 0" to 3 bits (Bits #7, #6 and #5) in Octet#3 ?

Upon #linkedinfamily feedback and further check, I could find the clear explanation of Type-of-Address from TS 23.040. ??

9.2.3.8 TP-Destination-Address (TP-DA)

The TP-Destination-Address field is formatted according to the formatting rules of address fields. The first ‘#’ encountered in TP-DA indicates where the address for SMSC routing purposes is terminated. Additional ‘*’s or ‘#’s can be present in the following digits, and all these digits including the first ‘#’ are subaddress digits.

9.1.2.5 Address fields

The Type-of-Address field format is as follows:

Type-of-number:

Bits 6 5 4 (==> Must be 0 based indexing in my understanding)

0 0 0 Unknown

0 0 1 International number

0 1 0 National number

0 1 1 Network specific number

1 0 0 Subscriber number

1 0 1 Alphanumeric, (coded according to 3GPP TS 23.038 [9] GSM 7-bit default alphabet)

1 1 0 Abbreviated number

1 1 1 Reserved for extension

Now, I could conclude the National Number (10) isn't a valid value as per specification. Thanks all for your valuable feedback to correct my understanding. ?? ??