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Changes retransmit delay to no longer use buckets #961

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Changes retransmit delay to no longer use buckets #961

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19 changes: 17 additions & 2 deletions examples/simple_repeater/MyMesh.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -396,12 +396,27 @@ int MyMesh::calcRxDelay(float score, uint32_t air_time) const {
}

uint32_t MyMesh::getRetransmitDelay(const mesh::Packet *packet) {
if(_prefs.tx_delay_factor == 0) {
MESH_DEBUG_PRINTLN("getRetransmitDelay: Total tx delay: %d", _prefs.tx_delay_factor);
return 5;
}

uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.tx_delay_factor);
return getRNG()->nextInt(0, 6) * t;
uint32_t total_delay = getRNG()->nextInt(5, t);
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@ripplebiz ripplebiz Oct 18, 2025

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This would make the maximum delay 't'. Whereas it used to be 5*t was the max.
This would change the interpretation of the _prefs values. Admins can set to some small fraction, like 0.1 (or smaller) if very small delays want to be experimented with. Currently max for the pref is 2.0 (I think), which is probably very wild/unrealistic.
Also, currently the minimum 'extra' delay is 0, and this introduces min of 5 which could be a fairly 'radical' change. For a first-try, I'd rather introducing JUST the granularity change... ie. no 6 buckets, and just continuous range instead

MESH_DEBUG_PRINTLN("getRetransmitDelay: Total tx delay: %d", total_delay);
return total_delay;
}

uint32_t MyMesh::getDirectRetransmitDelay(const mesh::Packet *packet) {
if(_prefs.direct_tx_delay_factor == 0) {
MESH_DEBUG_PRINTLN("getDirectRetransmitDelay: Total tx delay: %d", _prefs.direct_tx_delay_factor);
return 5;
}

uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
return getRNG()->nextInt(0, 6) * t;
uint32_t total_delay = getRNG()->nextInt(5, t);
MESH_DEBUG_PRINTLN("getDirectRetransmitDelay: Total tx delay: %d", total_delay);
return total_delay;
}

void MyMesh::onAnonDataRecv(mesh::Packet *packet, const uint8_t *secret, const mesh::Identity &sender,
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4 changes: 3 additions & 1 deletion src/Mesh.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,9 @@ bool Mesh::allowPacketForward(const mesh::Packet* packet) {
uint32_t Mesh::getRetransmitDelay(const mesh::Packet* packet) {
uint32_t t = (_radio->getEstAirtimeFor(packet->getRawLength()) * 52 / 50) / 2;

return _rng->nextInt(0, 5)*t;
uint32_t total_delay = getRNG()->nextInt(5, t);
MESH_DEBUG_PRINTLN("getRetransmitDelay: Total tx delay: %d", total_delay);
return total_delay;
}
uint32_t Mesh::getDirectRetransmitDelay(const Packet* packet) {
return 0; // by default, no delay
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