One peripheral to multiple Central Connection requirement

[Brajesh]

Hi All,

I need to implement a kinda a mesh network of Nordic device nodes placed nearby to act as a relay, for that I have a use case where following requirement.

1. One Peripheral to multiple central device connection.
2. MTU size larger than 27 (around 100 bytes) to attain higher throughput.

I'm using S130 Softdevice along with SDK 9.0.

Please let me know your comments about the design and whether i can achieve above two requirements.

Suggestions would be well appreciated.

Thanks Brajesh

[Petter Myhre]

What are your actual throughput requirements?

[Petter Myhre]

1. One Peripheral to multiple central device connection. - Unfortunately, acting in the peripheral role our SoftDevices can only hold a single connection.

2. MTU size larger than 27 (around 100 bytes) to attain higher throughput. - Currently our SoftDevices support and MTU of 23 bytes, where up to 20 bytes of user data available per packet. We plan to extend it, please see this question.

Edit 31.07.2015, added 2.

[Brajesh]

We want to attain around 251 bytes MTU as spec 4.2 allows and i have checked s130 complaints 4.2, so is that possible to have that MTU size with S130 ?

[Brajesh]

so that we can do larger data transfer in very less time (e.g. images, videos etc)

[Petter Myhre]

I'm asking about your throughput requirements because an increase in MTU doesn't give a proportional increase in throughput. The on air data rate is still 1 Mb/s with an increase in MTU, and if you lose a packet it is better if it is smaller rather than bigger. If you are interested in how to calculate the throughput, please see this.