hi,
I’ve finally played with SMS relay; just to summarize, it works as follows:
- delivery is first attempted via Gotenna network
- if destination is unavailable App offers delivery via SMS relay
- app contacts Gotenna servers; they relay SMS via Twilio SMS gateway(s) (local number for me)
- coordinates are relayed as plain text GPS, see example below
- responses via SMS relay are not supported yet
- senders may be using phone# or GID; recipient obviously must use number
Example of message via SMS relay:
goTenna Network Relay Message from 1415NXXXYYY
Text: text-contents
Location: username’s last location
Coordinates: 37.0000000000, -121.00000000000
GPS Timestamp: 20:15 - 15/10/17 GMT
Considering that:
- first half of delivery is already performed via IP (origin -> Gotenna)
- Gotenna already has some identity information for senders
- using SMS transport adds some level of inconvenience
i believe it would make more sense to make Gotenna -> Recipient hop over IP as usual, if available.
There are a few downsides:
- recipients need to poll for messages, potentially wasting battery; mostly a solved problem
- gotenna needs to maintain infrastructure to support large pool of smartphone clients constantly connected
- data coverage may be more limited than SMS (but we already rely on it to send SMS relay message out)
- Gotenna would be able to track locations
But there are immediate upsides to consider too:
- relayed messages would appear within same Gotenna interface/thread (not in the SMS smartphone app like now)
- relayed messages would be no different from native Gotenna - can be replied to, can contain clickable GPS links etc
- GID becomes first class citizen (no different from phone#)
- this opens route for Gotenna repeater, see below
- SMS can still be used as last resort, if recipient is not connecting via IP transport and is using phone#
Gotenna repeater, which is simply a smartphone paired with Gotenna, packed in MOAN-like enclosure, using cellular or WiFi internet, would be relaying Gotenna messages via local Gotenna coverage or IP. It’s quite similar to Internet-linked HAM repeaters, which allow to dramatically grow mesh coverage.
The downside is effort to operate directory and forwarding infrastructure, and combine IP mesh with existing mesh protocol (but i suspect some of last part can be hidden). In simpler implementation pairs of Gotenna’s apps could be linked together via IP, removing need for central directory (some effort for IP rendezvous is still required).
–igor