BGP aggregate prefix

RouterOS Forwarding Protocols
1

Hi

I just experienced a problem on advertised prefix flapping in my bgp connection to upstream.

I have a pair of ccr1036, each of them running 3 full route, and exchange the route using 2 x delicates port and 2 bgp sessions to exchange route between two.

And I had breakdown my /22 subnet into multiple /28 network for my user to use. My upstream only allow me to advertise prefix shorter than /24, therefore I use the aggregate function to aggregate into /24 and /22 to send to my upstream.

The upstreams connected to one of two CCR report that our prefix is flapping very frequently, like once in couple minutes. That make my advertisement not stable and have connection problem with remote network.

The flapping does not exist between the ccr, and on the other CCR. only happen to one CCR, all upstream.

Since I am only allow to advertise 22-24 prefix lenght. I suspect it is about route aggregation, and I had open the BGP debug log, it said something like remove aggregate prefix once a while.

I am using vlan, vrrp, fastpath, no firewall filter, conntract.running 6.28

Hope if anyone give me some insight.

2

Can you post the log messages?

3

The log file was too big aa require to enable the debug mode.


At anyway, I had managed the issue by not using the aggregate function on the bad router, and redistribute the aggregated prefix from other good router.

Need to schedule the reboot sometime, as if the goos router become bad, I will lost all aggregated prefix.

4

Have you submitted this as a bug yet?

It appears to have happened to someone else running 6.28 as well

http://forum.mikrotik.com/t/disater-all-router-dies-at-the-sametime/88757/1

5

That was me…hehe