4 ms·

Fredrik, Thingsquare CTO here. Glad to see an interest in this article, and happy to prepare more detailed information about how the system works and performs.

Fredrik, Thingsquare CTO here. Glad to see an interest in this article, and happy to prepare more detailed information about how the system works and performs. There's of course tons of information that we're happy to discuss :) Anything else in particular that you would like to know more about?

Arnt 9y ago
How does average/high-percentile RTT increase with network diameter? How does average hop count increase with maximum diameter?
sathackr 9y ago
Thanks for stopping by to comment, I have a good bit of respect for C-level executives that take the time and risk to comment in public forums. Let me color the remainder of my comment by saying that my experience is in the 802.11/Wifi land and may not directly apply to the systems Thinksquare uses. I have been working in (802.11) wireless for ~20 years and have seen pretty much every implementation of mesh fail spectacularly. One implementation I got to see fail up close was Kissimmee/St-Cloud's Tropos system. Some of the largest obstacles were outlined in the linked page -- how to figure out what's going on. It seems Thingsquare is not forming the mesh on the 802.11 networks, but on a separate low power network. Not sure all of the intimate details of this 802.15.4e setup but I imagine it has some of the issues of 802.11 One big problem on 802.11 networks is that each radio is half duplex, and once you get 2-3 hops out, speed an latency are severely impacted. The variability in latency caused by retransmits in a noisy environment wreaks havoc on TCP window scaling. I've always heard about this self-healing, route-around-problem-areas magic, but have never seen it work well in practice. You generally don't know if a link is bad until you try to use it, particularly if you aren't actively testing the links in order to reduce your power consumption. But then actively testing the links can itself generate interference with other links. Some of these have been "solved" by using devices with dual radios, one for the 'mesh' network and one for user access. Maybe someone finally has some magic that works, but I've seen many municipalities and corporations promised the moon, spent millions on networks that then fall flat on their face.

Arnt 9y ago

How does average/high-percentile RTT increase with network diameter? How does average hop count increase with maximum diameter?

sathackr 9y ago

Thanks for stopping by to comment, I have a good bit of respect for C-level executives that take the time and risk to comment in public forums. Let me color the remainder of my comment by saying that my experience is in the 802.11/Wifi land and may not directly apply to the systems Thinksquare uses. I have been working in (802.11) wireless for ~20 years and have seen pretty much every implementation of mesh fail spectacularly. One implementation I got to see fail up close was Kissimmee/St-Cloud's Tropos system. Some of the largest obstacles were outlined in the linked page -- how to figure out what's going on. It seems Thingsquare is not forming the mesh on the 802.11 networks, but on a separate low power network. Not sure all of the intimate details of this 802.15.4e setup but I imagine it has some of the issues of 802.11 One big problem on 802.11 networks is that each radio is half duplex, and once you get 2-3 hops out, speed an latency are severely impacted. The variability in latency caused by retransmits in a noisy environment wreaks havoc on TCP window scaling. I've always heard about this self-healing, route-around-problem-areas magic, but have never seen it work well in practice. You generally don't know if a link is bad until you try to use it, particularly if you aren't actively testing the links in order to reduce your power consumption. But then actively testing the links can itself generate interference with other links. Some of these have been "solved" by using devices with dual radios, one for the 'mesh' network and one for user access. Maybe someone finally has some magic that works, but I've seen many municipalities and corporations promised the moon, spent millions on networks that then fall flat on their face.