This post is older than 2 years and might not be relevant anymore
More Info: Consider searching for newer posts

nrf9160 mqtt keep alive longer than 30 minutes not working

sdk: 1.6

modem fw: 1.2.3

Hi,

Been trying to test mqtt every which way and not getting any success with mqtt keep alive longer than 30 minutes, the mqtt connection is only maintained when the keepalive is less than 30 minutes. Two problems are:

1. setting KEEPALIVE values 1800 or larger than that, the connection just gets dropped.

2. Cant figure out how to set 'will message'. What I currently have in the code I get, "mqtt_connect... -12". which is #define ENOMEM 12 /* Not enough space */.

Removing the will message solves the connection issue, but keepalive issue persists.

Regards

Noaman

6443.2021-09-17-proj.conf

#
# Copyright (c) 2019 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
#

menu "HTTP application update sample"

config DOWNLOAD_HOST
	string "Download host name"

config DOWNLOAD_FILE
	string "The file to download"

config APPLICATION_VERSION
	int "Application version"
	default 1

config USE_HTTPS
	bool
	prompt "Use HTTPS for download"

endmenu

menu "MQTT simple sample"
config MQTT_PUB_TOPIC
	string "MQTT publish topic"
	default "my/publish/topic"

config MQTT_SUB_TOPIC
	string "MQTT subscribe topic"
	default "my/subscribe/topic"

config MQTT_CLIENT_ID
	string "MQTT Client ID"
	help
	  Use a custom Client ID string. If not set, the client ID will be
	  generated based on IMEI number (for nRF9160 based targets) or
	  randomly (for other platforms).
	default "ltetest"

config MQTT_BROKER_HOSTNAME
	string "MQTT broker hostname"
	default "test.cloudmqtt.com"

config MQTT_BROKER_PORT
	int "MQTT broker port"
	default 16993

config MQTT_MESSAGE_BUFFER_SIZE
	int "MQTT message buffer size"
	default 1024

config MQTT_PAYLOAD_BUFFER_SIZE
	int "MQTT payload buffer size"
	default 1024

config BUTTON_EVENT_PUBLISH_MSG
	string "The message to publish on a button event"
	default "Hello from nRF91 MQTT Simple Sample"

config MQTT_KEEPALIVE
	int ""
	default 3600
	
config BUTTON_EVENT_BTN_NUM
	int "The button number"
	default 1

config MQTT_RECONNECT_DELAY_S
	int "Seconds to delay before attempting to reconnect to the broker."
	default 5

config LTE_CONNECT_RETRY_DELAY_S
	int "Seconds to delay before attempting to retry LTE connection."
	default 120

config MQTT_TLS_SEC_TAG
	int "TLS credentials security tag"
	default 24

config MQTT_TLS_SESSION_CACHING
	bool "Enable TLS session caching"

config MQTT_TLS_PEER_VERIFY
	int "Set peer verification level"
	default 0
	help
		Set to 0 for VERIFY_NONE, 1 for VERIFY_OPTIONAL, and 2 for
		VERIFY_REQUIRED.

endmenu

menu "Zephyr Kernel"
source "Kconfig.zephyr"
endmenu

module = MQTT_SIMPLE
module-str = MQTT Simple
source "${ZEPHYR_BASE}/subsys/logging/Kconfig.template.log_config"

#include "myMQTT.h"
#include "myLTE.h"
#include <net/mqtt.h>
#include <net/socket.h>
#include <random/rand32.h>
#include "global.h"
#include "myHTTPs.h"

#include <modem/at_cmd.h>
#include <modem/at_notif.h>
#include <power/reboot.h>

#include <logging/log.h>

char mqtt_client_id[17] = "ltet001122334455";
uint32_t msgIdCnt = 1000;
bool mqttInitialized = false;
bool mqttConnecting = false;


char CONFIG_MQTT_BROKER_HOSTNAME[50] = "custom.cloudmqtt.com"; //"tailor.cloudmqtt.com";
int CONFIG_MQTT_BROKER_PORT = 14339;
int CONFIG_MQTT_BROKER_PORT_SECURE = 8883; //24339;
char CONFIG_MQTT_USER[30] = "username";
char CONFIG_MQTT_PASSWORD[30] = "password"; 


/* Buffers for MQTT client. */
static uint8_t rx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static uint8_t tx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
static uint8_t payload_buf[CONFIG_MQTT_PAYLOAD_BUFFER_SIZE];

/* The mqtt client struct */
static struct mqtt_client client;

/* MQTT Broker details. */
static struct sockaddr_storage broker;

/* Connected flag */
static bool mqttIsConnected;

/* File descriptor */
static struct pollfd fds;

#define mqttWillMsg "nrf_lte_connection_terminate"
#define mqttWillTopic "lte/willTopic"

bool flag_is_mqtts_updated = false;

uint8_t mqttInitErrorCounter = 0;
uint8_t mqttConnectErrorCounter = 0;
uint8_t mqttPollErrorCounter = 0;
uint8_t mqttPublishErrorCounter = 0;

/**@brief Function to print strings without null-termination
 */
static void data_print(uint8_t *prefix, uint8_t *data, size_t len)
{
	char buf[len + 1];

	memcpy(buf, data, len);
	buf[len] = 0;
	if (DEBUG_PRINT_MQTT) printk("%s%s\n", prefix, buf);
}

/**@brief Function to publish data on the configured topic
 */
static int data_publish(struct mqtt_client *c, enum mqtt_qos qos,
	uint8_t *data, size_t len)
{
	struct mqtt_publish_param param;

	param.message.topic.qos = qos;
	param.message.topic.topic.utf8 = CONFIG_MQTT_PUB_TOPIC;
	param.message.topic.topic.size = strlen(CONFIG_MQTT_PUB_TOPIC);
	param.message.payload.data = data;
	param.message.payload.len = len;
	param.message_id = msgIdCnt++;//sys_rand32_get();
	param.dup_flag = 0;
	param.retain_flag = 0;

	if (DEBUG_PRINT_MQTT)
	{
		data_print("Publishing: ", data, len);
		// printk("to topic: %s len: %u\n", CONFIG_MQTT_PUB_TOPIC, (unsigned int)strlen(CONFIG_MQTT_PUB_TOPIC));
	}
	return mqtt_publish(c, &param);
}

/**@brief Function to subscribe to the configured topic
 */
static int subscribe(void)
{
 /*
	struct mqtt_topic subscribe_topic = {
		.topic = {
			.utf8 = CONFIG_MQTT_SUB_TOPIC,
			.size = strlen(CONFIG_MQTT_SUB_TOPIC)
		},
		.qos = MQTT_QOS_1_AT_LEAST_ONCE
	};

	const struct mqtt_subscription_list subscription_list = {
		.list = &subscribe_topic,
		.list_count = 1,
		.message_id = 1234
	};

	printk("Subscribing to: %s len %u\n", CONFIG_MQTT_SUB_TOPIC,
		(unsigned int)strlen(CONFIG_MQTT_SUB_TOPIC));

	return mqtt_subscribe(&client, &subscription_list);
        */
}

/**@brief Function to read the published payload.
 */
static int publish_get_payload(struct mqtt_client *c, size_t length)
{
	//uint8_t *buf = payload_buf;
	//uint8_t *end = buf + length;

	//if (length > sizeof(payload_buf)) {
	//	return -EMSGSIZE;
	//}

	//while (buf < end) {
	//	int ret = mqtt_read_publish_payload(c, buf, end - buf);

	//	if (ret < 0) {
	//		int err;

	//		if (ret != -EAGAIN) {
	//			return ret;
	//		}

	//		if (DEBUG_PRINT_MQTT) printk("mqtt_read_publish_payload: EAGAIN\n");

	//		err = poll(&fds, 1, K_SECONDS(CONFIG_MQTT_KEEPALIVE));
	//		if (err > 0 && (fds.revents & POLLIN) == POLLIN) {
	//			continue;
	//		} else {
	//			return -EIO;
	//		}
	//	}

	//	if (ret == 0) {
	//		return -EIO;
	//	}

	//	buf += ret;
	//}

	return 0;
}

/**@brief MQTT client event handler
 */
void mqtt_evt_handler(struct mqtt_client *const c,
		      const struct mqtt_evt *evt)
{
	int err;

	switch (evt->type) {
	case MQTT_EVT_CONNACK:
		if (evt->result != 0) {
			if (DEBUG_PRINT_MQTT) printk("MQTT connect failed: %d", evt->result);
			break;
		}

		if (DEBUG_PRINT_MQTT) printk("MQTT client connected");
		subscribe();
		break;

	case MQTT_EVT_DISCONNECT:
		if (DEBUG_PRINT_MQTT) printk("MQTT client disconnected: %d", evt->result);
		break;

	case MQTT_EVT_PUBLISH: {
		const struct mqtt_publish_param *p = &evt->param.publish;

		if (DEBUG_PRINT_MQTT) printk("MQTT PUBLISH result=%d len=%d",
			evt->result, p->message.payload.len);
		err = publish_get_payload(c, p->message.payload.len);

		if (p->message.topic.qos == MQTT_QOS_1_AT_LEAST_ONCE) {
			const struct mqtt_puback_param ack = {
				.message_id = p->message_id
			};

			/* Send acknowledgment. */
			mqtt_publish_qos1_ack(&client, &ack);
		}

		if (err >= 0) {
			data_print("Received: ", payload_buf,
				p->message.payload.len);
			/* Echo back received data */
			data_publish(&client, MQTT_QOS_1_AT_LEAST_ONCE,
				payload_buf, p->message.payload.len);
		} else {
			if (DEBUG_PRINT_MQTT) printk("publish_get_payload failed: %d", err);
			if (DEBUG_PRINT_MQTT) printk("Disconnecting MQTT client...");

			err = mqtt_disconnect(c);
			if (err) {
				if (DEBUG_PRINT_MQTT) printk("Could not disconnect: %d", err);
			}
		}
	} break;

	case MQTT_EVT_PUBACK:
		if (evt->result != 0) {
			if (DEBUG_PRINT_MQTT) printk("MQTT PUBACK error: %d", evt->result);
			break;
		}

		if (DEBUG_PRINT_MQTT) printk("PUBACK packet id: %u", evt->param.puback.message_id);
		break;

	case MQTT_EVT_SUBACK:
		if (evt->result != 0) {
			if (DEBUG_PRINT_MQTT) printk("MQTT SUBACK error: %d", evt->result);
			break;
		}

		if (DEBUG_PRINT_MQTT) printk("SUBACK packet id: %u", evt->param.suback.message_id);
		break;

	case MQTT_EVT_PINGRESP:
		if (evt->result != 0) {
			if (DEBUG_PRINT_MQTT) printk("MQTT PINGRESP error: %d", evt->result);
		}
		break;

	default:
		if (DEBUG_PRINT_MQTT) printk("Unhandled MQTT event type: %d", evt->type);
		break;
	}
}

/**@brief Resolves the configured hostname and
 * initializes the MQTT broker structure
 */
static int broker_init(void)
{
	int err;
	struct addrinfo *result;
	struct addrinfo *addr;
	struct addrinfo hints = {
		.ai_family = AF_INET,
		.ai_socktype = SOCK_STREAM
	};

	err = getaddrinfo(CONFIG_MQTT_BROKER_HOSTNAME, NULL, &hints, &result);
	if (err) {
		if (DEBUG_PRINT_MQTT) printk("getaddrinfo failed: %d", err);
		return -ECHILD;
	}

	addr = result;

	/* Look for address of the broker. */
	while (addr != NULL) {
		/* IPv4 Address. */
		if (addr->ai_addrlen == sizeof(struct sockaddr_in)) {
			struct sockaddr_in *broker4 =
				((struct sockaddr_in *)&broker);
			char ipv4_addr[NET_IPV4_ADDR_LEN];

			broker4->sin_addr.s_addr =
				((struct sockaddr_in *)addr->ai_addr)
				->sin_addr.s_addr;
			broker4->sin_family = AF_INET;
			broker4->sin_port = htons(CONFIG_MQTT_BROKER_PORT);

			inet_ntop(AF_INET, &broker4->sin_addr.s_addr,
				  ipv4_addr, sizeof(ipv4_addr));
			if (DEBUG_PRINT_MQTT) printk("IPv4 Address found %s", ipv4_addr);

			break;
		} else {
			if (DEBUG_PRINT_MQTT) printk("ai_addrlen = %u should be %u or %u",
				(unsigned int)addr->ai_addrlen,
				(unsigned int)sizeof(struct sockaddr_in),
				(unsigned int)sizeof(struct sockaddr_in6));
		}

		addr = addr->ai_next;
	}

	/* Free the address. */
	freeaddrinfo(result);

	return err;
}

#if defined(CONFIG_NRF_MODEM_LIB)
#define IMEI_LEN 15
#define CGSN_RESPONSE_LENGTH 19
#define CLIENT_ID_LEN sizeof("nrf-") + IMEI_LEN
#else
#define RANDOM_LEN 10
#define CLIENT_ID_LEN sizeof(CONFIG_BOARD) + 1 + RANDOM_LEN
#endif /* defined(CONFIG_NRF_MODEM_LIB) */

/* Function to get the client id */
static const uint8_t* client_id_get(void)
{
	static uint8_t client_id[MAX(sizeof(CONFIG_MQTT_CLIENT_ID),
				     CLIENT_ID_LEN)];

	if (strlen(CONFIG_MQTT_CLIENT_ID) > 0) {
		snprintf(client_id, sizeof(client_id), "%s",
			 CONFIG_MQTT_CLIENT_ID);
		goto exit;
	}

 #if defined(CONFIG_NRF_MODEM_LIB)
	char imei_buf[CGSN_RESPONSE_LENGTH + 1];
	int err;

	if (!IS_ENABLED(CONFIG_AT_CMD_SYS_INIT)) {
		err = at_cmd_init();
		if (err) {
			if (DEBUG_PRINT_MQTT) printk("at_cmd failed to initialize, error: %d", err);
			goto exit;
		}
	}

	err = at_cmd_write("AT+CGSN", imei_buf, sizeof(imei_buf), NULL);
	if (err) {
		if (DEBUG_PRINT_MQTT) printk("Failed to obtain IMEI, error: %d", err);
		goto exit;
	}

	imei_buf[IMEI_LEN] = '\0';

	snprintf(client_id, sizeof(client_id), "nrf-%.*s", IMEI_LEN, imei_buf);
 #else
	uint32_t id = sys_rand32_get();
	snprintf(client_id, sizeof(client_id), "%s-%010u", CONFIG_BOARD, id);
 #endif /* !defined(NRF_CLOUD_CLIENT_ID) */

 exit:
	if (DEBUG_PRINT_MQTT) printk("client_id = %s", client_id);

	return client_id;
}

/**@brief Initialize the MQTT client structure
 */
static int client_init(struct mqtt_client *client)
{
	int err;

	mqtt_client_init(client);

	err = broker_init();
	if (err) {
		if (DEBUG_PRINT_MQTT) printk("Failed to initialize broker connection");
		return err;
	}

	struct mqtt_utf8 mqtt_user;
	struct mqtt_utf8 mqtt_password;
        struct mqtt_utf8 myWillMsg; //mqtt_user;
        struct mqtt_topic myWillTopic;

    mqtt_user.utf8 = (uint8_t *)(CONFIG_MQTT_USER);
	mqtt_user.size = strlen(CONFIG_MQTT_USER);

	mqtt_password.utf8 = (uint8_t *)(CONFIG_MQTT_PASSWORD);
	mqtt_password.size = strlen(CONFIG_MQTT_PASSWORD);

	/* MQTT client configuration */
	client->broker = &broker;
	client->evt_cb = mqtt_evt_handler;
	client->client_id.utf8 = client_id_get();
	client->client_id.size = strlen(client->client_id.utf8);
	client->password = &mqtt_password;
	client->user_name = &mqtt_user;
	client->protocol_version = MQTT_VERSION_3_1_1;

	/* MQTT buffers configuration */
	client->rx_buf = rx_buffer;
	client->rx_buf_size = sizeof(rx_buffer);
	client->tx_buf = tx_buffer;
	client->tx_buf_size = sizeof(tx_buffer);    

        myWillTopic.topic.utf8 = (uint8_t *)mqttWillTopic;
	myWillTopic.topic.size = strlen(myWillTopic.topic.utf8);
        myWillTopic.qos = MQTT_QOS_1_AT_LEAST_ONCE;
	client->will_topic = &myWillTopic;

        myWillMsg.utf8 = (uint8_t *)mqttWillMsg;
	myWillMsg.size = strlen(myWillMsg.utf8);
	client->will_message = &myWillMsg;
//client->will_topic->topic.size = myWillTopic.size;



	/* MQTT transport configuration */
 #if defined(CONFIG_MQTT_LIB_TLS)
	struct mqtt_sec_config *tls_cfg = &(client->transport).tls.config;
	static sec_tag_t sec_tag_list[] = { CONFIG_MQTT_TLS_SEC_TAG };

	if (DEBUG_PRINT_MQTT) printk("TLS enabled");
	client->transport.type = MQTT_TRANSPORT_SECURE;

	tls_cfg->peer_verify = CONFIG_MQTT_TLS_PEER_VERIFY;
	tls_cfg->cipher_count = 0;
	tls_cfg->cipher_list = NULL;
	tls_cfg->sec_tag_count = ARRAY_SIZE(sec_tag_list);
	tls_cfg->sec_tag_list = sec_tag_list;
	tls_cfg->hostname = CONFIG_MQTT_BROKER_HOSTNAME;

 #if defined(CONFIG_NRF_MODEM_LIB)
	tls_cfg->session_cache = IS_ENABLED(CONFIG_MQTT_TLS_SESSION_CACHING) ?
					    TLS_SESSION_CACHE_ENABLED :
					    TLS_SESSION_CACHE_DISABLED;
 #else
	/* TLS session caching is not supported by the Zephyr network stack */
	tls_cfg->session_cache = TLS_SESSION_CACHE_DISABLED;

 #endif

 #else
	client->transport.type = MQTT_TRANSPORT_NON_SECURE;
 #endif

	return err;
}

/**@brief Initialize the file descriptor structure used by poll.
 */
static int fds_init(struct mqtt_client *c)
{
	if (c->transport.type == MQTT_TRANSPORT_NON_SECURE) {
		fds.fd = c->transport.tcp.sock;
	} else {
#if defined(CONFIG_MQTT_LIB_TLS)
		fds.fd = c->transport.tls.sock;
#else
		return -ENOTSUP;
#endif
	}

	fds.events = POLLIN;

	return 0;
}

void myMqttWorkHandler(struct k_work *work)
{
  	//char msg[100] = 
	printk("Now publishing mqtt data\n");
	int ret = data_publish(&client,
					MQTT_QOS_0_AT_MOST_ONCE,
					CONFIG_BUTTON_EVENT_PUBLISH_MSG,
					sizeof(CONFIG_BUTTON_EVENT_PUBLISH_MSG)-1);
	if (ret) {
		printk("Publish failed: %d\n", ret);
	}
	else
	{
		printk("mqtt sent successfully\n");
	}
}

void test5_mqttKeepAlive()
{
  int err = 0;
  uint32_t connect_attempt = 0;


	err = client_init(&client);
	if (err != 0) {
		if (DEBUG_PRINT_MQTT) printk("client_init: %d", err);
		return;
	}

 do_connect:
	if (connect_attempt++ > 0) {
		if (DEBUG_PRINT_MQTT) printk("Reconnecting in %d seconds...",
			CONFIG_MQTT_RECONNECT_DELAY_S);
		k_sleep(K_SECONDS(CONFIG_MQTT_RECONNECT_DELAY_S));
	}
	err = mqtt_connect(&client);
	if (err != 0) {
		if (DEBUG_PRINT_MQTT) printk("mqtt_connect %d", err);
		goto do_connect;
	}

	err = fds_init(&client);
	if (err != 0) {
		if (DEBUG_PRINT_MQTT) printk("fds_init: %d", err);
		return;
	}

	while (1) {
		err = poll(&fds, 1, mqtt_keepalive_time_left(&client));
		if (err < 0) {
			if (DEBUG_PRINT_MQTT) printk("poll: %d", errno);
			break;
		}

		err = mqtt_live(&client);
		if ((err != 0) && (err != -EAGAIN)) {
			if (DEBUG_PRINT_MQTT) printk("ERROR: mqtt_live: %d", err);
			break;
		}

		if ((fds.revents & POLLIN) == POLLIN) {
			err = mqtt_input(&client);
			if (err != 0) {
				if (DEBUG_PRINT_MQTT) printk("mqtt_input: %d", err);
				break;
			}
		}

		if ((fds.revents & POLLERR) == POLLERR) {
			if (DEBUG_PRINT_MQTT) printk("POLLERR");
			break;
		}

		if ((fds.revents & POLLNVAL) == POLLNVAL) {
			if (DEBUG_PRINT_MQTT) printk("POLLNVAL");
			break;
		}
	}

	if (DEBUG_PRINT_MQTT) printk("Disconnecting MQTT client...");

	err = mqtt_disconnect(&client);
	if (err) {
		if (DEBUG_PRINT_MQTT) printk("Could not disconnect MQTT client: %d", err);
	}
	goto do_connect;
}

  • Hi Oyvind,

    I have attached the updated modem trace.

    once again: keepalive is 40 minutes

    mqtt publish freq: 40 min

    modem fw: 1.2.3

    ESP is connecting via Wifi. I have confirmed with Bell that connections of any sort are not being reset or terminated by them in 30 minutes. IP lease time is also in hours/days not in minutes.

    I do not want 30 minute keep alive. I want >12 hour keepalive. Our use-case for asset tracking requires 12 hours pings on idle and more frequent pings on motion. so we could be sending 5-10 pings on a daily basis for typical application. I do not want to establish a new connection every time as it adds up on power consumption as well as data requirements on reconnection especially on TLS. TLS session caching does reduce data consumption and connection time but it is still more than what a keepalive duration of 12 hours would allow us to acheive.

    trace-2022-04-19T03-16-06.348Z.bin

    *** Booting Zephyr OS build v2.7.99-ncs1-1  ***
    Flash regions		Domain		Permissions
    00 02 0x00000 0x18000 	Secure		rwxl
    03 31 0x18000 0x100000 	Non-Secure	rwxl
    
    Non-secure callable region 0 placed in flash region 2 with size 32.
    
    SRAM region		Domain		Permissions
    00 03 0x00000 0x08000 	Secure		rwxl
    04 31 0x08000 0x40000 	Non-Secure	rwxl
    
    Peripheral		Domain		Status
    00 NRF_P0               Non-Secure	OK
    01 NRF_CLOCK            Non-Secure	OK
    02 NRF_RTC0             Non-Secure	OK
    03 NRF_RTC1             Non-Secure	OK
    04 NRF_NVMC             Non-Secure	OK
    05 NRF_UARTE1           Non-Secure	OK
    06 NRF_UARTE2           Secure		SKIP
    07 NRF_TWIM2            Non-Secure	OK
    08 NRF_SPIM3            Non-Secure	OK
    09 NRF_TIMER0           Non-Secure	OK
    10 NRF_TIMER1           Non-Secure	OK
    11 NRF_TIMER2           Non-Secure	OK
    12 NRF_SAADC            Non-Secure	OK
    13 NRF_PWM0             Non-Secure	OK
    14 NRF_PWM1             Non-Secure	OK
    15 NRF_PWM2             Non-Secure	OK
    16 NRF_PWM3             Non-Secure	OK
    17 NRF_WDT              Non-Secure	OK
    18 NRF_IPC              Non-Secure	OK
    19 NRF_VMC              Non-Secure	OK
    20 NRF_FPU              Non-Secure	OK
    21 NRF_EGU0             Non-Secure	OK
    22 NRF_EGU1             Non-Secure	OK
    23 NRF_EGU2             Non-Secure	OK
    24 NRF_EGU3             Non-Secure	OK
    25 NRF_EGU4             Non-Secure	OK
    26 NRF_EGU5             Non-Secure	OK
    27 NRF_DPPIC            Non-Secure	OK
    28 NRF_REGULATORS       Non-Secure	OK
    29 NRF_PDM              Non-Secure	OK
    30 NRF_I2S              Non-Secure	OK
    31 NRF_GPIOTE1          Non-Secure	OK
    
    SPM: NS image at 0x18200
    SPM: NS MSP at 0x20014368
    SPM: NS reset vector at 0x1bb11
    SPM: prepare to jump to Non-Secure image.
    *** Booting Zephyr OS build v2.7.99-ncs1-1  ***
    [00:00:00.231,018] <inf> mqtt_simple: The MQTT simple sample started
    [00:00:00.231,048] <inf> mqtt_simple: Disabling PSM and eDRX
    [00:00:00.231,781] <inf> mqtt_simple: LTE Link Connecting...
    [00:00:04.703,369] <inf> mqtt_simple: LTE Link Connected!
    [00:00:04.894,226] <inf> mqtt_simple: IPv4 Address found 34.227.176.196
    [00:00:04.897,033] <dbg> mqtt_simple.client_id_get: client_id = nrf-352656101085366
    [00:00:05.352,478] <inf> mqtt_simple: MQTT client connected
    In Timer Callback - time: 24897
    [00:00:24.900,238] <inf> mqtt_simple: Publishing: {"channel":"lte","topic":"location","data":"f~
    [00:00:24.900,268] <inf> mqtt_simple: Time: 24900 - to topic: feed/ len: 5
    POLLHUP
    [00:40:25.240,753] <inf> mqtt_simple: Disconnecting MQTT client...
    [00:40:25.240,997] <inf> mqtt_simple: MQTT client disconnected: -104
    [00:40:25.241,027] <err> mqtt_simple: Could not disconnect MQTT client: -104
    [00:40:25.241,027] <inf> mqtt_simple: Reconnecting in 60 seconds...
    [00:41:25.792,602] <inf> mqtt_simple: MQTT client connected
    In Timer Callback - time: 2724897
    [00:45:24.900,390] <inf> mqtt_simple: Publishing: {"channel":"lte","topic":"location","data":"f~
    [00:45:24.900,421] <inf> mqtt_simple: Time: 2724900 - to topic: feed/ len: 5
    

  • Thanks for providing the update. 

    Just to clarify, has Bell or Rogers support confirmed the NAT timeout on the network? NAT timeout is considered as a "chain", meaning that you are only "as strong as the weakest link" - i.e. if your one of your network chains has a lower than 350 seconds, that will be the NAT timeout for this specific network/APN.

    Perhaps GSMA's Whitepaper on Improving Energy Efficiency for Mobile IoT. can offer some insight on this. 

    Kind regards,
    Øyvind

Related