8.3 International Mobile Subscriber Identity (IMSI)

29.2743GPP3GPP Evolved Packet System (EPS)Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C)Release 16Stage 3TS

International Mobile Subscriber Identity (IMSI) is transferred via GTP tunnels. The sending entity copies the value part of the IMSI into the Value field of the IMSI IE. IMSI is defined in 3GPP TS 23.003 [2].

Bits

Octets

8

7

6

5

4

3

2

1

1

Type = 1 (decimal)

2 to 3

Length = n

4

Spare

Instance

5

Number digit 2

Number digit 1

6

Number digit 4

Number digit 3

n+4

Number digit m

Number digit m-1

Figure 8.3-1: IMSI

Octets 5 to (n+4) represent the IMSI value in international number format as described in ITU-T Rec E.212 [64], encoded as TBCD digits, i.e. digits from 0 through 9 are encoded "0000" to "1001". When there is an odd number of digits, bits 8 to 5 of the last octet are encoded with the filler "1111". The maximum number of digits is 15.