[CUWiN-Dev] volatile ETX & routing

[Bill Comisky]

We've had our network users reporting that their connections have been 
less stable since moving from OSPF to HSLSD.

First some qualtitative observations that've been reported:

- Connections will go up and down, at one moment look good (good ping
   times, good download rates) and then bad the next.

- Adding a new node to the system makes everyones connections locally go
   haywire for a bit then things tend to settle down; this seemed
   especially apparent when booting up a local laptop node to do upgrades.
   This may have been more prevalent when there were only a few HSLS nodes
   up in the network.

- The routing tables are very dynamic, with routes sometimes changing
   several times in the span of (one?) minute.

- The routes chosen (often short lived) sometimes seem a poor choice,
   routing through someone much farther away that has a poor connection to
   everyone to get to a nearby gateway.

Quantitatively, the ETX metric looks volatile.  Attached is a snapshot of 
the normalized (1-256) ETX metrics (linear and logarithmic plots) for 
routes between one of our gateways and the nodes it can see for the last 
hour.  The network traffic is very low during this time as seen by the 
other graph, the bandwidth through the gateway's wireless interface.

I'm going to start logging the routing table changes to get an idea of how 
often they're changing.. though my sample resolution will only be every 
couple minutes.

Bill

--
Bill Comisky
bcomisky at pobox.com
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