I'd be careful with just reducing timeouts... A 2 seconds purge timeout together with a default 1 second OGM interval seems to me like asking for a lot of route flapping in the best case. And potential, temporary routing loops in the worst case.

What we typically do is decrease the batman-adv originator interval instead, which you can do with "batctl orig_interval".

Some people seem to get confused about stale entries from vanished nodes. They shouldn't have much impact on performance. If that dead node was a selected router to another node but has not been heard of for 5 sequence numbers (5x originator interval, BATADV_TQ_GLOBAL_WINDOW_SIZE) then this other node will use an alternative neighbor node as a router with the next OGM with a seqno > 5 from this alternative.

Regards, Linus

On Thu, Jun 27, 2024 at 07:43:59PM +0000, BEAL Romain wrote:

Hi,

I want to use batman-adv for highly mobile nodes. All of my nodes are robot or radio module embedded on a human, for example.

Losing a node is very common and batman-adv needs to self-reconfigure quickly in my case. Adding a node is very common too, maybe for only few seconds or minutes.

The default configuration doesn't work very well for my use case. But when I use this configuration :

#define BATADV_PURGE_TIMEOUT 2000 #define BATADV_TT_LOCAL_TIMEOUT 6000 #define BATADV_TT_CLIENT_ROAM_TIMEOUT 6000 #define BATADV_TT_CLIENT_TEMP_TIMEOUT 6000 #define BATADV_ORIG_WORK_PERIOD 500 #define BATADV_DAT_ENTRY_TIMEOUT (5*600)

The result is better. I have some unstable connection for only 5 seconds when I loss a node. Have you done any testing for this type of use ?

Thanks for help

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