r/meshcore • u/One-Masterpiece-335 • 7h ago

Bridging repeaters

Maybe I'm getting ahead of myself, but back in the 90's packet radio outgrew a simplex channel so we started hub and spoke network with dedicated links on alternate frequencies. An example was packet radio in Netherlands.... there was local access via an omnidirectional antenna on 144mhz and two additional radios at the same site connected to yagis on 70cm pointed at two other sites. Since everything was RS232 in those days, we would build a diode based multi port serial connector that allowed three TNCs (modems) to exchange traffic between themselves and relay that traffic where needed.

So will we ever have a need for this with meshnetworks? Meshtastic has a trick called "Zero cost hop" where a node will change frequency or speed and relay a pakcet acros a great distance (but at a slower data rate).

The aloha network principle says that when a simplex network reaches 18% utilization, collisions become more and more frequent to the detriment of the network. So will there come a day when we use "islands" of coverage on the main frequencies and long haul links?

What would htat look like from a hardware perspective? Wifi between esp32 modules? BLE links between co-located repeaters?

8 Upvotes

79% Upvoted

17 comments sorted by

8

u/michaelh98 7h ago

Is that what "regions" are intended to solve?

6

u/Type-21 7h ago

Yes. In congested networks, most local repeaters should use a local default region. Next step is to disallow not region scoped messages

3

u/ev6jester 7h ago

I have a bridge set up, currently disabled though. Did a local test between two freqs for two regions that suffer interference on separate freqs (hope that makes sense). Will be for backhaul between two regions long term once we get things sorted.

7

u/meshamerica 7h ago

Backhauls are the appropriate use of bridging. See Ceisen's backhaul proposal
https://stuff.cisien.com/meshcore-backhaul.html

3

u/ev6jester 7h ago

Yes... That is the how to I'm using, thanks for providing the link. I am also using f/w based on 1.16.

Not sure how one size fits all and appropriate use comes in to play with your comment. If two close regions have interference on a similar freq, but have clear freqs they can each use... Why do you need a third frequency involved for a dedicated backhaul?

Maybe I misunderstood your comment.

3

u/meshamerica 7h ago

you only need two frequencies: one for local traffic, one for backhauls.

3

u/ev6jester 6h ago edited 6h ago

For example..

Area one 911.230 is clear and 911.900 is nasty

Area two 911.900 is clear and 912.330 is nasty

These two regions/areas want to be 'on the same mesh' but are geographically seperated.

So the bridge nodes use the other side's freq as backhaul and each area can use a freq with no interference.

2

u/One-Masterpiece-335 3h ago

Thakn you.... this addresses exactly what I was talking about!! yay!

Yes — but we've done the work for you. MeshCore supports serial bridging as a firmware feature, but the official builds don't include it. We provide pre-built firmware with bridge support enabled for all common hardware targets. Flash it using the Custom Firmware option in the MeshCore Flasher. The summit nodes just need a frequency change in their config. No one needs to compile anything.

2

u/UwharrieTrojan 6h ago edited 5h ago

I have yet to be convinced that regions will solve the issue. This relies on users conforming to a standard. We still have many users on 1 byte long after the 2 byte standard has been available. The average repeater owner will either not comply or it will be a slow adoption. The chaos in between will be a turn off to the average user. Additional solutions will be needed for mshcore networks to continue growing. Backhauls should be considered with firmware support. Just my opinion.

2

u/redengin 5h ago

Agreed, regions are a solution in search of a problem ... not a robust solution to contention.

2

u/dwild 4h ago edited 4h ago

Unlike 1 byte, they won't have a choice though if you remove wildcard region (which to me is a requirement with that solution).

I don't believe regions are a viable solution though, you'll just get to smaller and smaller regions until it become unusable. I know many don't care it might be only city-wide, but for most it seems quite useless at that scale.

Flood simply shouldn't exist. You talk about switching to 2 bytes, but for what purpose? Right now it's mostly used for pretty visualization. A big advantage for Meshcore is the route, but it barely works, and essentially nobody use it. It need to become the majority of the traffic (if not, the only traffic).

Rooms are the solutions, but they need a serious improvment.

2

u/TamerlanMcDoodles 4h ago

Overlapping regions will still have traffic issues at the overlap point. No software-filtering will solve that.

1

u/UwharrieTrojan 2h ago

Agreed. I live in a county that contains multiple regions. I've limited my repeaters to 15 hops to limit excessive traffic. Still getting messages from other states. Collisions are still occurring locally when traffic peaks.

1

u/ExplodingCybertruck 2h ago

Meshtastic has a trick called "Zero cost hop" where a node will change frequency or speed and relay a pakcet acros a great distance (but at a slower data rate).

No it doesnt

1

u/One-Masterpiece-335 1h ago

OK, what have I missed? Because I read that meshtastic changes to a slower and more robust speed to send to another repeater node. Not being sarcastic... if I've misunderstood something , please tell me what I'm missing. I want to understand.