4G

终端在PDN connectivity request中access_pt_name中携带。

msg_type = 208 (0xd0) (PDN connectivity request)
lte_esm_msg
  pdn_connectivity_req
    pdn_type = 3 (0x3) (Ipv4v6)
    req_type = 1 (0x1) (initial request)
    info_trans_flag_incl = 0 (0x0)
    access_pt_name_incl = 1 (0x1)
    access_pt_name_
      num_acc_pt_val = 4 (0x4)
      acc_pt_name_val[0] = 3 (0x3) (length)
      acc_pt_name_val[1] = 105 (0x69) (i)
      acc_pt_name_val[2] = 109 (0x6d) (m)
      acc_pt_name_val[3] = 115 (0x73) (s)

网络分配APN在Activate default EPS bearer context request的acc_pt_name_val中携带。

msg_type = 193 (0xc1) (Activate default EPS bearer context request)
    access_point
      num_acc_pt_val = 23 (0x17)
      acc_pt_name_val[0] = 3 (0x3) (length)
      acc_pt_name_val[1] = 105 (0x69) (i)
      acc_pt_name_val[2] = 109 (0x6d) (m)
      acc_pt_name_val[3] = 115 (0x73) (s)
      acc_pt_name_val[4] = 6 (0x6) (length)
      acc_pt_name_val[5] = 109 (0x6d) (m)
      acc_pt_name_val[6] = 110 (0x6e) (n)
      acc_pt_name_val[7] = 99 (0x63) (c)
      acc_pt_name_val[8] = 48 (0x30) (0)
      acc_pt_name_val[9] = 48 (0x30) (0)
      acc_pt_name_val[10] = 50 (0x32) (2)
      acc_pt_name_val[11] = 6 (0x6) (length)
      acc_pt_name_val[12] = 109 (0x6d) (m)
      acc_pt_name_val[13] = 99 (0x63) (c)
      acc_pt_name_val[14] = 99 (0x63) (c)
      acc_pt_name_val[15] = 52 (0x34) (4)
      acc_pt_name_val[16] = 54 (0x36) (6)
      acc_pt_name_val[17] = 48 (0x30) (0)
      acc_pt_name_val[18] = 4 (0x4) (length)
      acc_pt_name_val[19] = 103 (0x67) (g)
      acc_pt_name_val[20] = 112 (0x70) (p)
      acc_pt_name_val[21] = 114 (0x72) (r)
      acc_pt_name_val[22] = 115 (0x73) (s)

5G

在携带PDU session establishment request的UL NAS transport中。
此UL NAS transport中包含的pay_load_container携带PDU session establishment request，dnn字段携带APN信息。