Hi, In July 2007 Philip Craig reported the following issue with 'forward delay'=0 in great detail without receiving an answer. Has Philip's message got lost or was his analysis wrong? The problem becomes a real problem if you bridge a fast LAN to a slow port like a bluetooth pan for example. https://lists.linux-foundation.org/pipermail/bridge/2007-July/005476.html Philip Craig philipc at snapgear.com > Hi, > > If you set the bridge forward delay to 0 with: > brctl setfd br0 0 > then the bridge does not learn addresses for the first 20 seconds, > and so it floods everything during this time. > > The reason for this is that hold_time() returns 0 after a topology > change, br_fdb_update() is a no-op if hold_time() is 0 (so that > 'brctl setmaxage br0 0' can be used to disable learning), and the > topology change flag isn't cleared for max_age seconds, so nothing > is learnt during that time. > > It seems that the intent of hold_time() is to expire entries that are > older than forward_delay seconds at the time of the topology change, > which it does, but then it keeps on checking this expiry again for > max_age seconds, and bases these checks on the current time rather > than the time of the change. > > A quick fix for the forward delay 0 case would be to skip the > topology change check if stp is disabled, but if I understand things > correctly then the expiry isn't right for non-zero cases either. _______________________________________________ Bridge mailing list Bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/bridge
