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电信卡无信号问题

news 来源：原创 2024/9/30 23:17:47

问题背景：
A产品和B产品插同样的电信卡。A产品有信号，B产品无信号。从APN配置界面看，A产品和B产品不同。A产品为ctnet，B产品为ctlte。将B产品的APN也配置为ctnet，其他apn参数也配置相同。但是B仍然没有信号。
担心机卡绑定导致。重新办两张卡，现象也是一样。

问题分析：
界面上的APN无论是ctlte，还是ctnet，终端都是使用了携带用户名密码的ctlte 进行attach。都在attach的过程就被拒绝了。

如下是终端上报ia类型（即initial attach）的apn：

08:14:32.511016	[0xB0E3]	LTE NAS ESM Plain OTA Outgoing Message
pkt_version = 1 (0x1)
rel_number = 9 (0x9)
rel_version_major = 5 (0x5)
rel_version_minor = 0 (0x0)
eps_bearer_id_or_skip_id = 0 (0x0)
prot_disc = 2 (0x2) (EPS session management messages)
trans_id = 10 (0xa)
msg_type = 218 (0xda) (ESM information response)
lte_esm_msgesm_info_resacc_pt_name_incl = 1 (0x1)access_point_namenum_acc_pt_val = 6 (0x6)acc_pt_name_val[0] = 5 (0x5) (length)acc_pt_name_val[1] = 99 (0x63) (c)acc_pt_name_val[2] = 116 (0x74) (t)acc_pt_name_val[3] = 108 (0x6c) (l)acc_pt_name_val[4] = 116 (0x74) (t)acc_pt_name_val[5] = 101 (0x65) (e)//ctlteprot_config_incl = 1 (0x1)prot_configext = 1 (0x1)conf_prot = 0 (0x0)num_recs = 8 (0x8)prot_or_container[0]id = 49699 (0xc223) (CHAP)prot_or_containerprot_len = 36 (0x24)chap_protcode = 1 (0x1)identifier = 0 (0x0)rfc1994_chap_challenge//chap鉴权value_size = 16 (0x10)value[0] = 128 (0x80)value[1] = 129 (0x81)value[2] = 147 (0x93)value[3] = 147 (0x93)value[4] = 128 (0x80)value[5] = 129 (0x81)value[6] = 147 (0x93)value[7] = 147 (0x93)value[8] = 128 (0x80)value[9] = 129 (0x81)value[10] = 147 (0x93)value[11] = 147 (0x93)value[12] = 128 (0x80)value[13] = 129 (0x81)value[14] = 147 (0x93)value[15] = 147 (0x93)name_size = 15 (0xf)name[0] = 99 (0x63)name[1] = 116 (0x74)name[2] = 119 (0x77)name[3] = 97 (0x61)name[4] = 112 (0x70)name[5] = 64 (0x40)name[6] = 109 (0x6d)name[7] = 121 (0x79)name[8] = 99 (0x63)name[9] = 100 (0x64)name[10] = 109 (0x6d)name[11] = 97 (0x61)name[12] = 46 (0x2e)name[13] = 99 (0x63)name[14] = 110 (0x6e)prot_or_container[1]id = 49699 (0xc223) (CHAP)prot_or_containerprot_len = 36 (0x24)chap_protcode = 2 (0x2)identifier = 0 (0x0)rfc1994_chap_respvalue_size = 16 (0x10)value[0] = 69 (0x45)value[1] = 173 (0xad)value[2] = 192 (0xc0)value[3] = 66 (0x42)value[4] = 219 (0xdb)value[5] = 74 (0x4a)value[6] = 216 (0xd8)value[7] = 83 (0x53)value[8] = 217 (0xd9)value[9] = 36 (0x24)value[10] = 137 (0x89)value[11] = 23 (0x17)value[12] = 109 (0x6d)value[13] = 198 (0xc6)value[14] = 18 (0x12)value[15] = 108 (0x6c)name_size = 15 (0xf)name[0] = 99 (0x63)name[1] = 116 (0x74)name[2] = 119 (0x77)name[3] = 97 (0x61)name[4] = 112 (0x70)name[5] = 64 (0x40)name[6] = 109 (0x6d)name[7] = 121 (0x79)name[8] = 99 (0x63)name[9] = 100 (0x64)name[10] = 109 (0x6d)name[11] = 97 (0x61)name[12] = 46 (0x2e)name[13] = 99 (0x63)name[14] = 110 (0x6e)

被网络拒绝，收到attach reject：

08:14:32.657010	[0xB0EC]	LTE NAS EMM Plain OTA Incoming Message
pkt_version = 1 (0x1)
rel_number = 9 (0x9)
rel_version_major = 5 (0x5)
rel_version_minor = 0 (0x0)
security_header_or_skip_ind = 0 (0x0)
prot_disc = 7 (0x7) (EPS mobility management messages)
msg_type = 68 (0x44) (Attach reject)
lte_emm_msgemm_attach_rejectcause_value = 19 (0x13) (ESM failure)esm_msg_container_incl = 1 (0x1)esm_msg_containereps_bearer_id_or_skip_id = 0 (0x0)prot_disc = 2 (0x2) (EPS session management messages)trans_id = 10 (0xa)msg_type = 209 (0xd1) (PDN connectivity reject)lte_esm_msgpdn_connectivity_rejesm_causeesm_cause = 29 (0x1d) (User authentication failed)

虽然没有提供A的开机log，modem日志也确实太多。直觉猜测，需要把B attach使用的apn从ctlte配置为ctnet，并且参考A的apn不用chap鉴权。A产品的ia apn应该也是 ctnet。

验证方法很简单，B产品参考A产品建立的ctnet apn的type为defaul，hipri。再添加ia类型. 即type为“”defaul，hipri，ia“”。
果真，这么修改困扰的无信号问题就解决了。B产品成功显示信号强度。

B回复给网络的ia apn变为ctnet。

07:43:36.553574	[0xB0E3]	LTE NAS ESM Plain OTA Outgoing Message
pkt_version = 1 (0x1)
rel_number = 9 (0x9)
rel_version_major = 5 (0x5)
rel_version_minor = 0 (0x0)
eps_bearer_id_or_skip_id = 0 (0x0)
prot_disc = 2 (0x2) (EPS session management messages)
trans_id = 4 (0x4)
msg_type = 218 (0xda) (ESM information response)
lte_esm_msgesm_info_resacc_pt_name_incl = 1 (0x1)access_point_namenum_acc_pt_val = 6 (0x6)acc_pt_name_val[0] = 5 (0x5) (length)acc_pt_name_val[1] = 67 (0x43) (C)acc_pt_name_val[2] = 84 (0x54) (T)acc_pt_name_val[3] = 78 (0x4e) (N)acc_pt_name_val[4] = 69 (0x45) (E)acc_pt_name_val[5] = 84 (0x54) (T)prot_config_incl = 0 (0x0)ext_prot_config_incl = 0 (0x0)

网络回复了attach accept。通过attach_result = 1 (0x1) (EPS only) ，cause_value = 18 (0x12) (CS domain not available)， IMSVoPS = 0 (0x0) (IMS Vo PS Session in S1 Mode not supported)，可以确认这只是一张流量卡。不支持通话。

07:43:36.908005	[0xB0EC]	LTE NAS EMM Plain OTA Incoming Message
pkt_version = 1 (0x1)
rel_number = 9 (0x9)
rel_version_major = 5 (0x5)
rel_version_minor = 0 (0x0)
security_header_or_skip_ind = 0 (0x0)
prot_disc = 7 (0x7) (EPS mobility management messages)
msg_type = 66 (0x42) (Attach accept)
lte_emm_msgemm_attach_acceptattach_result = 1 (0x1) (EPS only)emm_cause_incl = 1 (0x1)emm_causecause_value = 18 (0x12) (CS domain not available)T3402_incl = 0 (0x0)T3423_incl = 0 (0x0)equ_plmns_incl = 0 (0x0)emergnecy_num_list_incl = 0 (0x0)eps_netwk_feature_support_incl = 1 (0x1)eps_netwk_feature_supportlength = 1 (0x1)CPCIoT = 0 (0x0)ERwoPDN = 0 (0x0)ESRPS = 0 (0x0)CS_LCS = 0 (0x0) (No info about support of loc service via cs is available)EPC_LCS = 0 (0x0) (Location Services via EPC not supported)EMC_BS = 1 (0x1) (Emergency bearer services in S1 Mode supported)IMSVoPS = 0 (0x0) (IMS Vo PS Session in S1 Mode not supported)

通过RIL日志也可以看到apn添加ia类型后，AP侧下发了ia 类型APN的更新：

15:40:18.940 D/RILJ    ( 3385): [3755]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctlte, protocol:IPV4V6, authType:3, username:ctwap@mycdma.cn, password:vnet.mobi [SUB0]
15:40:19.151 D/RILJ    ( 3385): [3757]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctlte, protocol:IPV4V6, authType:3, username:ctwap@mycdma.cn, password:vnet.mobi [SUB0]
15:41:05.730 D/RILJ    ( 3385): [3828]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctlte, protocol:IPV4V6, authType:3, username:ctwap@mycdma.cn, password:vnet.mobi [SUB0]
15:41:07.645 D/RILJ    ( 3385): [3829]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctlte, protocol:IPV4V6, authType:3, username:ctwap@mycdma.cn, password:vnet.mobi [SUB0]
15:41:07.829 D/RILJ    ( 3385): [3830]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctlte, protocol:IPV4V6, authType:3, username:ctwap@mycdma.cn, password:vnet.mobi [SUB0]
15:42:26.031 D/RILJ    ( 3385): [3836]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctnet, protocol:IPV4V6, authType:-1, username:, password: [SUB0]
15:42:27.751 D/RILJ    ( 3385): [3837]> RIL_REQUEST_SET_INITIAL_ATTACH_APN, apn:ctnet, protocol:IPV4V6, authType:-1, username:, password: [SUB0]