NimBLE question regarding multiple connections

[Christoph Jabs <ch...@jabs-family.de>]

Hello all,

I have a question regarding the nimble stack.

I'm working on a BLE test framework to evaluate BLE and different stack 
implementations.
Nimble is already implemented into the framework for small experiment 
setups, but when I try to run a experiment with more then two peripherals 
with the nimble stack, I get the return code `BLE_ERR_CONN_REJ_RESOURCES` 
from the function `ble_gap_connect`.
When looking at a packet log of the HCI communication I see, that the 
controller responds with command status `0x0d` (Connection rejected due to 
limited ressources) to the `LE Create Connection` command.
The thing that is confusing me is, that the same experiment works with a 
different stack and the packetlogs do not look signifficantly different 
between the two stacks.

My first problem for experiments with multiple peripherals was, that the 
`MYNEWT_VAL_BLE_MAX_CONNECTIONS` parameter in the config was set to 1.
That was my mistake, but I fixed that.
My question is if there is a different configuration parameter that I'm 
missing or if you have a different idea what could be the problem.

For additional information: The test devices in the experiments are 
Raspberry Pi 3s and the nimble build is based on the linux port from the 
repository.

Thanks in advance

- Christoph

---
Christoph Johannes Jabs
christoph@jabs-family.de
Tel. +49 152 53372087
Martin-Vollmer-Weg 19
72144 Dusslingen

Re: NimBLE question regarding multiple connections

[Łukasz Rymanowski <lu...@codecoup.pl>]

Hi Christoph,

If you are using Raspberry Pi it means you are using only Nimble Host and
not the Nimble Controller.
That means changing MYNEWT_VAL_BLE_MAX_CONNECTIONS allocates only Host
resources for more connection, but we do not have influence for the
Controller.
And as you said, the controller is replying with 0x0d` (Connection rejected
due to limited resources) when you try to create more connections and we
cannot do anything about that.
I suggest to use Nimble Controller as well to get full Nimble experience :).

Best
Łukasz

On Tue, 30 Apr 2019 at 15:12, Christoph Jabs <ch...@jabs-family.de>
wrote:

> Hello all,
>
> I have a question regarding the nimble stack.
>
> I'm working on a BLE test framework to evaluate BLE and different stack
> implementations.
> Nimble is already implemented into the framework for small experiment
> setups, but when I try to run a experiment with more then two peripherals
> with the nimble stack, I get the return code `BLE_ERR_CONN_REJ_RESOURCES`
> from the function `ble_gap_connect`.
> When looking at a packet log of the HCI communication I see, that the
> controller responds with command status `0x0d` (Connection rejected due to
> limited ressources) to the `LE Create Connection` command.
> The thing that is confusing me is, that the same experiment works with a
> different stack and the packetlogs do not look signifficantly different
> between the two stacks.
>
> My first problem for experiments with multiple peripherals was, that the
> `MYNEWT_VAL_BLE_MAX_CONNECTIONS` parameter in the config was set to 1.
> That was my mistake, but I fixed that.
> My question is if there is a different configuration parameter that I'm
> missing or if you have a different idea what could be the problem.
>
> For additional information: The test devices in the experiments are
> Raspberry Pi 3s and the nimble build is based on the linux port from the
> repository.
>
> Thanks in advance
>
> - Christoph
>
> ---
> Christoph Johannes Jabs
> christoph@jabs-family.de
> Tel. +49 152 53372087
> Martin-Vollmer-Weg 19
> 72144 Dusslingen
>
>
>