Proxy connexion time

RE: Proxy connexion time

Ryjan — Wed, 28 Apr 2021 19:15:21 GMT

Ok, now that it's been tested I figured that I would follow up on what I've done.

I was able to significantly improve the connecting speed to a proxy by changing the value defined as MESH_GATT_PROXY_NETWORK_ID_ADV_INT_MS. For some reason I could not find any references to this definition in my searches here in the Dev Zone. After Edvin mentioned that the advertisements are at about 2 second intervals that helped to home in on this definition since it was sett a 2000ms. Still with an advertisement at every 2 seconds, sometimes it could take 30 seconds to connect. My guess it that the 2 second interval is too similar to the scanning interval of the phone that is looking for a proxy to connect to. I picked one of Apple's recommended intervals (760ms in this case) and the connecting time improved to about 8 seconds or less. And most of the time less than 5 seconds. That's much more acceptable. The default values for MESH_GATT_PROXY_NETWORK_ID_ADV_INT_MS are in nrf_mesh_config_core.h.

It appears to be a scanning interval alignment issue.

RE: Proxy connexion time

Edvin — Thu, 15 Apr 2021 07:44:40 GMT

[quote user="titan vista"]I have the same issue and since this did not have a posted solution I figured that i would jump in.[/quote]

We can give it a go, but please create a new ticket if this answer doesn't solve it for you, as it is probably not the same problem as the original post.

What is your central? What is the central scan window and scan interval? And what channels is it scanning on? (did you change anything regarding scan channels)?

Is df:a8:66:b5:51:c9 the device you are connecting to? (I can't tell from the sniffer trace snippet). Have you modified it's advertisement channels?

I suspect that you are using a long scan interval and/or too short scan window. As far as I can see, df:a8:66:b5:51:c9 sends three advertisements every ~2 seconds, so a central would have the possibility to connect every 2 seconds. Why it doesn't do that, I can't say from the sniffer trace. I think this requires more information about the central/scanner/master.

RE: Proxy connexion time

Ryjan — Thu, 08 Apr 2021 14:15:57 GMT

I have the same issue and since this did not have a posted solution I figured that i would jump in.

I setup the sniffer and applied a MAC filter and an empty PDU filter. Below is a screenshot of a time when it took more than 16 seconds to connect. It appears that the device is advertising fairly often and some devices are requesting the scan response, but it appears that when the device trying to make a proxy connection finds it, the connection is made very quickly.

No.	Time	Source	PHY	Protocol	Length	Delta time (µs end to start)	SN	NESN	More Data	Event counter	Info
18981	10061.463	fb:23:fb:c2:7c:9b	LE 1M	LE LL	12	150µs				0	SCAN_REQ
18982	10061.464	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
18983	10061.464	df:a8:66:b5:51:c9	LE 1M	LE LL	26	301µs				0	ADV_IND
18984	10061.465	df:a8:66:b5:51:c9	LE 1M	LE LL	26	498µs				0	ADV_IND
18985	10061.466	6e:e3:45:3f:b4:30	LE 1M	LE LL	12	147µs				0	SCAN_REQ
18986	10061.466	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
18987	10063.467	df:a8:66:b5:51:c9	LE 1M	LE LL	26	2000446µs				0	ADV_IND
18988	10063.467	c3:dd:20:1e:4c:9b	LE 1M	LE LL	12	151µs				0	SCAN_REQ
18989	10063.468	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
18990	10063.468	df:a8:66:b5:51:c9	LE 1M	LE LL	26	301µs				0	ADV_IND
18991	10065.473	df:a8:66:b5:51:c9	LE 1M	LE LL	26	2004588µs				0	ADV_IND
18992	10066.312	df:a8:66:b5:51:c9	LE 1M	BT Mesh Beacon	30	839329µs				0	Secure Network Beacon
18993	10067.477	df:a8:66:b5:51:c9	LE 1M	LE LL	26	1164775µs				0	ADV_IND
18994	10067.478	c3:dd:20:1e:4c:9b	LE 1M	LE LL	12	150µs				0	SCAN_REQ
18995	10067.479	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
18996	10067.480	df:a8:66:b5:51:c9	LE 1M	LE LL	26	301µs				0	ADV_IND
18997	10067.480	fb:23:fb:c2:7c:9b	LE 1M	LE LL	12	150µs				0	SCAN_REQ
18998	10067.481	df:a8:66:b5:51:c9	LE 1M	LE LL	24	149µs				0	SCAN_RSP
18999	10069.483	df:a8:66:b5:51:c9	LE 1M	LE LL	26	2002979µs				0	ADV_IND
19000	10069.484	7a:3e:9f:0a:f9:4f	LE 1M	LE LL	12	150µs				0	SCAN_REQ
19001	10069.484	df:a8:66:b5:51:c9	LE 1M	LE LL	26	723µs				0	ADV_IND
19002	10069.485	df:a8:66:b5:51:c9	LE 1M	LE LL	26	498µs				0	ADV_IND
19003	10069.486	78:a5:a8:38:fe:96	LE 1M	LE LL	12	150µs				0	SCAN_REQ
19004	10069.486	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
19005	10071.491	df:a8:66:b5:51:c9	LE 1M	LE LL	26	2005099µs				0	ADV_IND
19006	10071.492	df:a8:66:b5:51:c9	LE 1M	LE LL	26	498µs				0	ADV_IND
19007	10073.495	df:a8:66:b5:51:c9	LE 1M	LE LL	26	2003150µs				0	ADV_IND
19008	10073.496	ee:0e:a3:0e:d3:67	LE 1M	LE LL	12	150µs				0	SCAN_REQ
19009	10073.496	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
19010	10075.496	df:a8:66:b5:51:c9	LE 1M	LE LL	26	1999498µs				0	ADV_IND
19011	10075.497	ee:0e:a3:0e:d3:67	LE 1M	LE LL	12	151µs				0	SCAN_REQ
19012	10075.498	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
19013	10075.499	df:a8:66:b5:51:c9	LE 1M	LE LL	26	301µs				0	ADV_IND
19014	10075.499	6e:e3:45:3f:b4:30	LE 1M	LE LL	12	148µs				0	SCAN_REQ
19015	10075.500	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
19016	10075.500	df:a8:66:b5:51:c9	LE 1M	LE LL	26	301µs				0	ADV_IND
19017	10075.521	df:a8:66:b5:51:c9	LE 1M	BT Mesh Beacon	30	22049µs				0	Secure Network Beacon
19018	10077.504	df:a8:66:b5:51:c9	LE 1M	LE LL	26	1982234µs				0	ADV_IND
19019	10077.504	cc:e9:c6:5c:a9:9a	LE 1M	LE LL	12	151µs				0	SCAN_REQ
19020	10077.505	df:a8:66:b5:51:c9	LE 1M	LE LL	24	149µs				0	SCAN_RSP
19021	10077.506	df:a8:66:b5:51:c9	LE 1M	LE LL	26	301µs				0	ADV_IND
19022	10077.506	7b:3e:8f:82:f9:89	LE 1M	LE LL	12	150µs				0	SCAN_REQ
19023	10077.507	df:a8:66:b5:51:c9	LE 1M	LE LL	24	150µs				0	SCAN_RSP
19024	10081.509	df:a8:66:b5:51:c9	LE 1M	LE LL	26	4003383µs				0	ADV_IND
19025	10081.510	5c:e4:3c:9b:80:82	LE 1M	LE LL	34	150µs				0	CONNECT_IND
19028	10081.535	Master_0x50657c51	LE 1M	LE LL	6	150µs	1	0	False	0	Control Opcode: LL_VERSION_IND
19029	10081.564	Master_0x50657c51	LE 1M	LE LL	6	29411µs	1	1	False	1	Control Opcode: LL_VERSION_IND
19032	10081.595	Slave_0x50657c51	LE 1M	LE LL	6	150µs	0	1	False	2	Control Opcode: LL_VERSION_IND
19033	10081.623	Master_0x50657c51	LE 1M	LE LL	9	29642µs	1	1	False	3	Control Opcode: LL_FEATURE_REQ
19034	10081.624	Slave_0x50657c51	LE 1M	L2CAP	16	151µs	1	0	False	3	Connection Parameter Update Request
19035	10081.653	Master_0x50657c51	LE 1M	L2CAP	10	29489µs	0	0	False	4	Connection Parameter Update Response (Accepted)
19036	10081.654	Slave_0x50657c51	LE 1M	LE LL	9	150µs	0	1	False	4	Control Opcode: LL_FEATURE_RSP
19037	10081.683	Master_0x50657c51	LE 1M	LE LL	12	29538µs	1	1	False	5	Control Opcode: LL_CONNECTION_UPDATE_IND

There is only this device and the provisioner on this network and the secure network beacon fires every 10 seconds as expected. There are several advertisements made by the device (MAC DF:A8:66:B5:51:C9) and as soon as the provisioner (MAC 5C:E4:3C:9B:80:82) the connecting is made very quickly. Is this just because the scanning windows on both devices are just missing each other, or is there another reason like excessive traffic on these channels causing the provisioner to not see the device?

Above was also listed to try and change the preprocessor definitions of MIN_CONN_INTERVAL and MAX_CONN_INTERVAL. From my understanding, these are the min and max values that can be accepted for connections after the device has been found and is in an active connection, rather than a value that controls the rate at which the device advertises. BEARER_ADV_INT_DEFAULT_MS seems to have more to do with the advertisement frequency, but it is set to 20ms and that is far quicker than I see advertisements on the sniffer. MESH_ADV_INTERVAL_DEFAULT also seems to be another place where an advertising rate can be set. I found references in this thread: https://devzone.nordicsemi.com/f/nordic-q-a/52057/change-advertisement-interval---ble-mesh.

I still haven't found what exactly controls the advertising rate for the proxy connection after provisioning, but it seems to advertise quite often according to the sniffer. What is causing the slow connection time? sometimes it's 5 seconds and sometimes it's over 30 seconds. What can be done to improve the performance?

RE: Proxy connexion time

Edvin — Fri, 07 Aug 2020 08:21:41 GMT

[quote user="Soter Giga "]Is those values right?[/quote]

Where are those defines used in your project?

The peripheral doesn't really decide the connection interval. The peripheral can request an interval, but the central decides in the end. A sniffer trace will reveal what sniffer trace you actually have.

RE: Proxy connexion time

Soter Giga — Thu, 06 Aug 2020 13:34:43 GMT

i used the light switch example!

Values are :

/** Minimum acceptable connection interval. */
#ifndef MIN_CONN_INTERVAL
#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(150,  UNIT_1_25_MS)  
#endif

/** Maximum acceptable connection interval. */
#ifndef MAX_CONN_INTERVAL
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(250,  UNIT_1_25_MS)  
#endif

Is those values right?

I didn't use the sniffer yet

RE: Proxy connexion time

Edvin — Thu, 06 Aug 2020 13:28:14 GMT

Yes. It is possible. but it depends on the advertising interval.

[quote user="Soter Giga "]On the advertising interval and connection interval, i never changed anything! i left the default values.[/quote]

What are those? What example did you start with?

How is it going with that sniffer trace?

RE: Proxy connexion time

Soter Giga — Thu, 06 Aug 2020 08:40:17 GMT

Hi,

Is it technicaly possible to have a connection time below 2 seconds?

On the advertising interval and connection interval, i never changed anything! i left the default values.

Please let me know!

Thank you

RE: Proxy connexion time

Edvin — Mon, 03 Aug 2020 09:01:07 GMT

[quote userid="90974" url="~/f/nordic-q-a/64271/proxy-connexion-time/262417"]Is it possible to send data without pairing?[/quote]

It is not possible to send data from the phone to the node without connecting, no.

It shouldn't take 15-20 seconds to connect to the device if you use a sensible advertising interval and connection interval. Did you change any of these? Is it possible to capture a sniffer trace from the connection? You can use the nRF Sniffer to capture this.

Best regards,

Edvin

RE: Proxy connexion time

Soter Giga — Thu, 30 Jul 2020 13:05:06 GMT

[quote userid="2115" url="~/f/nordic-q-a/64271/proxy-connexion-time/262386"][/quote]

From a phone, you have to connect to a device that supports PB-GATT, as described here:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.meshsdk.v4.2.0%2Fmd_doc_user_guide_modules_provisioning_main.html&anchor=provisioning_main_pb-gatt

Hi Thanks for you answer I have 3 devices in my mesh. After checking your link, i sawa my PBGATT activated. But this doesnt allow me send data without pairing. I have to connect to the node to be able to send data!

Is it possible to send data without pairing?

Thanks

RE: Proxy connexion time

Håkon Alseth — Thu, 30 Jul 2020 11:53:23 GMT

Hi,

The ble sniffer documentation is available here:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_sniffer_ble%2FUG%2Fsniffer_ble%2Fintro.html

And the firmware files needed is available for download here:

https://www.nordicsemi.com/Software-and-tools/Development-Tools/nRF-Sniffer-for-Bluetooth-LE/Download#infotabs

[quote user="Soter Giga "]Otherwise, if it is not possible to reduce the connection time in less than 2 seconds, is it possible to send data to the mesh without having to connect or pair?[/quote]

From a phone, you have to connect to a device that supports PB-GATT, as described here:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.meshsdk.v4.2.0%2Fmd_doc_user_guide_modules_provisioning_main.html&anchor=provisioning_main_pb-gatt

How many devices do you currently have in your mesh?

Kind regards,

Håkon

RE: Proxy connexion time

Soter Giga — Wed, 29 Jul 2020 11:42:24 GMT

Hi,

can you please tell me how to do that? I'm using the Light switch example!

Otherwise, if it is not possible to reduce the connection time in less than 2 seconds, is it possible to send data to the mesh without having to connect or pair?

Thanks for your help

RE: Proxy connexion time

Håkon Alseth — Wed, 29 Jul 2020 11:39:21 GMT

Hi,

Hard to say what is keeping the connection to use up to 20 seconds here, but if you provide a sniffer trace, its easier to pin point where the latency is introduced.

Could you provide a sniffer trace where the connection uses > 10 seconds to be fully established?

Kind regards,

Håkon