On Wed, 23 Nov 2005 09:10:56 -0800
Bob Snyder <oceansidebob@gmail.com> wrote:
> Hello,
>
> I have built a data link system (i.e. microwave radio) with bridges at
> both ends of the link (sort of back-to-back). The data link boxes have
> highly asymetrical RS-422 serial interfaces which are interfaced to
> the bridges with dscc4/hdlc/syncppp modules. Also, the bridges each
> have one regular ethernet port. The intention is to have the ethernet
> at one end appear to be connected to the ethernet at the other end.
> Also, one end is usually connected to a busy lan with lots of
> broadcast traffic. The bridges are running on 266 MHz Pentiums with no
> other load.
>
> The system works in general, but sometimes there are very long and
> erratic delay times (up to several seconds) when pinging through the
> link. If the radio link is brought up before the bridges are started,
> things seem to work well (ping times of ~10-15 ms). The problem seems
> to occur if the bridges are started before the radio link is brought
> up. Once the problem appears it will persist until the bridge is
> restarted.
>
> I wondered if the problems is that the MAC table was getting too big.
> I reduced the ageing time from 300 to 30 seconds, and this seemed to
> help (the MAC table got smaller), but the problem persists. Also the
> problem can be seen sometimes when not connected to the lan, so maybe
> I just don't have the bridge configured properly.
>
> Any help or suggestions appreciated.
>
Does the interface implement broadcast/muliticast?
Also the bridge takes 30 seconds to go through the learning phase
when interface is attached per STP spec.
--
Stephen Hemminger <shemminger@osdl.org>
OSDL http://developer.osdl.org/~shemminger